Visual Basic Controls/Visual Basic Controls.iso/vbcontrol/vidhandl/videohlp.txt

Text File | 1999-02-03 | 167.4 KB | 4,949 lines

@VIDEO HANDLING FUNCTIONS ver 2.0 INDEX

:Introduction:!!!INTRODUCTION
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌Video Handling Functions ▐          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀                            ver 2.0

    The header file <CRT.H> declares a group of functions that can access
  the screen either directly to video RAM or via BIOS calls, being really
  fast (when they use RAM access) and small (all them together takes only
  6.4k in small memory model).
    Access via BIOS is provided to allow them to work in any IBM compatible
  video adapter or in graphics mode.
    They are available in "compact", "small", "medium", "large" and "huge"
  memory models.

% Contents:
    ~Functions~
    ~Macro Functions~
    ~Global Variables~
    ~Data types~
    ~Declarations~ of Functions, Macros, Global Variables,...
    ~CRT.H~ header file help
    ~Appendix A~ => Portability
    ~Appendix B~ => Colors

:Functions
%FUNCTIONS:

    ■ ~crt_detect~      Detects current video mode, active display page,
                      number of columns, rows, current page start address,...
    ■ ~crt_init~        Calls crt_detect and updates crtwin_dta coordinates
                      to full screen and crtwin_just to CENTER_TEXT.
    ■ ~videomode~       Selects the number of columns and rows, via an input
                      argument. (Obsolete function, use crt_detect instead).
    ■ ~setcrtmode~      Changes current video mode, then call getcrtmode.
    ■ ~getcrtmode~      Gets current video mode, number of columns and current
                      page.
    ■ ~setcrtpage~      Selects video display page.
    ■ ~crt_gotoxy~      Changes cursor position.
    ■ ~crt_getxy~       Gets cursor position.
    ■ ~getcrtchar~      Gets the character from screen position (x,y).
    ■ ~getcrtcolor~     Gets the color from screen position (x,y).
    ■ ~biosprintc~      Sends a character into screen at position (x,y) via
                      BIOS.
    ■ ~printcn~         Sends a character at position (x,y) with no color.
    ■ ~printc~          Sends a character to screen with a color.
    ■ ~changecolor~     Changes the color from (x,y) position on screen.
    ■ ~printct~         Changes the character and/or color or keeps old
                      character and/or color of (x,y) position according to
                      a user given parameter.
    ■ ~printsn~         Writes a string at position (x,y) with no color.
    ■ ~prints~          Writes a string at position (x,y) with color.
    ■ ~printxy~         Writes a string on screen in any direction, with color.
    ■ ~printx~          Outputs a string with special text format instructions.
                      Writes the string with color.
    ■ ~printtext~       Writes a string inside current box at position(x,y),
                      continuing in the next line if text doesn't fit in one.
                      Writes string with color.
    ■ ~printsj~         Justified writes a string inside the current text box.
                      Writes string with color.
    ■ ~printsjc~        Enhanced printsj with special text color instructions.
    ■ ~printsnf~        Sends formatted output to screen using printsn.
    ■ ~printsf~         Sends formatted output to screen using prints.
    ■ ~printxyf~        Sends formatted output to screen using printxy.
    ■ ~printxf~         Sends formatted output to screen using printx.
    ■ ~printtextf~      Sends formatted output to screen using printtext.
    ■ ~printsjf~        Sends formatted output to screen using printsj.
    ■ ~printsjcf~       Sends formatted output to screen using printsjc.

    ■ ~fillscr~         Fills the screen with a character and a color.
    ■ ~barcolor~        Replaces the color of a text window.
    ■ ~fillbar~         Fills a text window with a character and a color.
    ■ ~fillbarw~        Fills a text window given by crtwin_dta with a
                      character and a color.
    ■ ~fillbox~         Replaces the characters and/or colors or keeps old
                      characters and/or colors of a text window according to a
                      user given parameter.
    ■ ~fillboxw~        Same as fillbox, but text window coordinates are given
                      by crtwin_dta.
    ■ ~crtframe~        Draws a colored text frame (single line, double line,
                      ...) (frame is a text box outline)
    ■ ~crtframew~       Draws a colored text frame with coordinates given by
                      crtwin_dta with single outline, double outline,...
    ■ ~mkline_aux~      It's mkline's character replacement algorithm.
    ■ ~mkline~          Draws frame lines replacing frame line intersections
                      by corresponding characters automatically.
    ■ ~crtwindow~       Draws a text box with border and title.
    ■ ~savevideo~       Saves the screen contents into a buffer.
    ■ ~restorevideo~    Writes a drawing saved in a buffer into screen.
    ■ ~savevideowin~    Saves a text window into a buffer.
    ■ ~restorevideowin~ Writes a drawing saved in a buffer into a text window
    ■ ~savevideow~      Saves a text window given by crtwin_dta into a buffer.
    ■ ~restorevideow~   Writes a drawing saved in a buffer into a text window
                      given by crtwin_dta.
    ■ ~savecrt~*        Saves the screen contents into a buffer with mode.
    ■ ~restorecrt~*     Writes a drawing saved in a buffer into screen with
                      mode.
    ■ ~savecrtwin~*     Saves a text window into a buffer with mode.
    ■ ~restorecrtwin~*  Writes a drawing saved in a buffer into a text window
                      with mode.
    ■ ~savecrtw~*       Saves a text window given by crtwin_dta into a buffer
                      with mode.
    ■ ~restorecrtw~*    Writes a drawing saved in a buffer into a text window
                      given by crtwin_dta with mode.

    ■ ~setcursorsh~     Changes cursor shape.
    ■ ~getcursorsh~     Gets cursor current shape.
    ■ ~setpalreg~       Sets a single palette register color (DAC register)
    ■ ~getpalreg~       Reads the color (DAC register) from a single palette
                      register.
    ■ ~setbordercolor~  Sets the border(overscan) color (DAC register)
    ■ ~getbordercolor~  Reads the border (overscan) color (DAC register)
    ■ ~setdacreg~       Sets the rgb color of a DAC register.
    ■ ~getdacreg~       Reads the rgb color of a DAC register.
    ■ ~setdacpage~      Selects video DAC color page.
    ■ ~setdacpgmode~    Selects video DAC paging mode.
    ■ ~getdacpgstate~   Gets current video DAC color page and paging mode.
    ■ ~setchrboxwidth~  Changes the character box width in VGA or better
                      monitors.
    ■ ~settextblink~    Toggles color/attribute intensity/blinking bit.
    ■ ~changechar~      Replaces text mode character patterns with user
                      specified patterns
    ■ ~changecharg~     Replaces graphics mode character patterns with user
                      specified patterns


  * To use them is needed to be defined a macro before including CRT.H, see
  ~CRT_FULL~

% See Also:
    ~Macro Functions~   ~Declarations~ of functions

% Return to:
    ~Introduction~   ~CRT.H~

:Macro Functions
%MACRO FUNCTIONS:

    ■ ~crtframe~ function:
       ■ ~moldura~      Draws a text frame with single outline (type = 0).
       ■ ~moldurad~     Draws a text frame with double outline (type = 1).

    ■ ~crtframew~ function: (text frame coordinates given by crtwin_dta)
       ■ ~molduraw~     Draws a text frame with single outline (type = 0).
       ■ ~molduradw~    Draws a text frame with double outline (type = 1).


    ■ ~mkline~ function:
       ■ ~linha_hor~    Draws a horizontal line with single outline.
       ■ ~linha_ver~    Draws a vertical line with single outline.
       ■ ~linhad_hor~   Draws a horizontal line with double outline.
       ■ ~linhad_ver~   Draws a vertical line with double outline.

    ■ ~crtwindow~ function:
       ■ ~janela~       Draws a text box with single outline.
       ■ ~janelad~      Draws a text box with double outline.

    ■ ~setcrtwin~       Defines active text box used by printsj and crtwindow.
                      Changes crtwin_dta global variable.

    ■ ~savevideo~       Is a macro when defined ~CRT_FULL~ or ~SAVECRT·~
    ■ ~restorevideo~    Is a macro when defined ~CRT_FULL~ or ~RESTORECRT·~
    ■ ~savevideowin~    Is a macro when defined ~CRT_FULL~ or ~SAVECRTWIN·~
    ■ ~restorevideowin~ Is a macro when defined ~CRT_FULL~ or ~RESTORECRTWIN·~
    ■ ~savevideow~      Is a macro when defined ~CRT_FULL~ or ~SAVECRTWIN·~
    ■ ~restorevideow~   Is a macro when defined ~CRT_FULL~ or ~RESTORECRTWIN·~

% See Also:
    ~Functions~

% Return to:
    ~Introduction~   ~CRT.H~

:Global Variables
%GLOBAL VARIABLES:

    ■  ~vmode_x~    =>  tells the expected number of columns in current text
                      mode.
    ■  ~vmode_y~    =>  tells the expected number of rows in current text mode.
    ■  ~vmode_mode~ =>  tells the expected video mode.
    ■  ~crt_direct~ =>  determines if the screen access goes directly to video
                      RAM (crt_direct==0) or via BIOS calls. (crt_direct!=0).
                      (default == 0)
    ■  ~crt_page~   =>  defines the text page that must be used by the
                      functions when they use access via BIOS. (default == 0).
    ■  ~video_addr~ =>  text mode video RAM base address. (Used when
                      crt_direct=0) (default = B800:0000h).
    ■  ~crt_EVGA_addr~ => determines EGA/VGA/SVGA adapter base port address.
                            (default (primary) = 3C0h / alternate = 2C0h)

    ■  ~crtframe_mat~  => array that holds the characters used by crtframe.
    ■  ~mkline_mat~    => array that holds the characters used by mkline and
                        mkline_aux.
    ■  ~crtwin_just~   => defines if text outputted by printsj will be left
                        justified, or center justified or right justified.
    ■  ~crtwin_dta~    => a struct that defines the active text box or text
                        window (that is used by printsj and crtwindow)
                        coordinates. See (struct ~crtwin~) type.
    ■  ~changechar_height~ => determines character pattern size (in bytes) and
                            height (in bits). Used by changechar and
                            changecharg.
    ■  ~changechar_func~   => _AX value in call to changechar. determines if
                            number of screen rows is recalculated or not.
    ■  ~changechar_blk~    => block to load character patterns in map 2. used
                            by changechar.

  Remark: vmode_x and vmode_y can be changed to any value intending to obtain
    interesting effects.
       All variables above can be accessed by the programmer. However, there
    are some global variables which are for exclusive and internal use of the
    functions. They are: crtvar_p, vmode_lm and vmode_am (if I haven't
    forgotten any)

% See Also:
    ~Data Types~

% Return to:
    ~Introduction~   ~CRT.H~

:Data Types
%DATA TYPES:

    ■  ~crtwin~      => struct that holds a window or box coordinates.
    ■  ~crtwin_inp~  => The structure of input arguments of crtwindow function.

% See Also:
    ~Global Variables~

% Return to:
    ~Introduction~   ~CRT.H~


:Declarations
%DECLARATION OF FUNCTIONS:

 void ~crt_detect~   (int mode);
 void ~crt_init~     (int mode);
 void ~videomode~    (int newmode);
 void ~setcrtmode~   (int mode);
 int  ~getcrtmode~   (void);
 void ~setcrtpage~   (int page);
 void ~crt_gotoxy~   (int x,  int y);
 int  ~crt_getxy~    (int *x, int *y);
 int  ~getcrtchar~   (int x,  int y);
 int  ~getcrtcolor~  (int x,  int y);
 void ~biosprintc~   (int chr, int x, int y, int color, int func);
 void ~printcn~      (int c, int x, int y);
 void ~printc~       (int c, int x, int y, int color);
 void ~changecolor~  (int x, int y, int color);
 void ~printct~      (int c, int x, int y, int color, unsigned int type);
 void ~printsn~      (char *s, int x, int y);
 void ~prints~       (char *s, int x, int y, int color);
 void ~printxy~      (char *s, int x, int y, int dx, int dy, int color);
 void ~printx~       (char *s, int x, int y, int color);
 int  ~printtext~    (char *s, int x, int y, int color);
 void ~printsj~      (char *s, int y, int color);
 void ~printsjc~     (char *s, int y, int color);
 int  ~printsnf~     (int x, int y,                            char *fmt,... );
 int  ~printsf~      (int x, int y,                 int color, char *fmt,... );
 int  ~printxyf~     (int x, int y, int dx, int dy, int color, char *fmt,... );
 int  ~printxf~      (int x, int y,                 int color, char *fmt,... );
 int  ~printtextf~   (int x, int y, int color, char *fmt,... );
 int  ~printsjf~     (int y, int color, char *fmt,... );
 int  ~printsjcf~    (int y, int color, char *fmt,... );
 void ~fillscr~   (int c, int color);
 void ~barcolor~  (int xi, int yi, int xf, int yf, int color);
 void ~fillbar~   (int c, int xi, int yi, int xf, int yf, int color);
 void ~fillbarw~  (int c, int color);
 void ~fillbox~   (int c, int xi, int yi, int xf, int yf, int color, int func);
 void ~fillboxw~  (int c, int color, int func);
 void ~crtframe~  (int xi, int yi, int xf, int yf, int color, unsigned type);
 void ~crtframew~    (int color, unsigned int type);
 void ~mkline_aux~   (int cnt, int var, unsigned mode, int pos, int color);
 void ~mkline~       (int cnt, int bgn, int end, int color, unsigned mode);
 void ~crtwindow~    (struct crtwin_inp p0);
 char far *~savevideo~        (char far *s);
 char far *~restorevideo~     (char far *s);
 char far *~savevideowin~     (char far *s, int xi, int yi, int xf, int yf);
 char far *~restorevideowin~  (char far *s, int xi, int yi, int xf, int yf);
 char far *~savevideow~       (char far *s);
 char far *~restorevideow~    (char far *s);
 char far *~savecrt~          (char far *s, int mode);
 char far *~restorecrt~       (char far *s, int mode);
 char far *~savecrtwin~    (char far *s, int xi,int yi,int xf,int yf,int mode);
 char far *~restorecrtwin~ (char far *s, int xi,int yi,int xf,int yf,int mode);
 char far *~savecrtw~      (char far *s, int mode);
 char far *~restorecrtw~   (char far *s, int mode);
 void ~setcursorsh~     (unsigned shape);
 int  ~getcursorsh~     (void);
 int  ~getpalreg~       (int regpal);
 void ~setpalreg~       (int regpal, int val);
 int  ~getbordercolor~  (void);
 void ~setbordercolor~  (int val);
 void ~getdacreg~    (int dacreg, char *red, char *green, char *blue);
 void ~setdacreg~    (int dacreg, char  red, char  green, char  blue);
 void ~setdacpgmode~ (int pgmode);
 void ~setdacpage~   (int page);
 int  ~getdacpgstate~   (void);
 void ~setchrboxwidth~  (int cmd);
 void ~settextblink~    (int cmd);
 void ~changechar~   (unsigned char *fmt, int ind, int qt);
 void ~changecharg~  (unsigned char *fmt, int rows);


%DECLARATION OF MACROS:

 void  ~moldura~  (int xi, int yi, int xf, int yf, int color);
 void  ~moldurad~ (int xi, int yi, int xf, int yf, int color);
 void  ~molduraw~    (int color);
 void  ~molduradw~   (int color);
 void  ~linha_hor~  (int y, int xi, int xf, int color);
 void  ~linha_ver~  (int x, int yi, int yf, int color);
 void  ~linhad_hor~ (int y, int xi, int xf, int color);
 void  ~linhad_ver~ (int x, int yi, int yf, int color);
 void  ~janela~   (struct crtwin_inp p0);
 void  ~janelad~  (struct crtwin_inp p0);
 void  ~setcrtwin~  (int xi, int yi, int xf, int yf);

 char far *~savevideo~        (char far *s);
 char far *~restorevideo~     (char far *s);
 char far *~savevideowin~     (char far *s, int xi, int yi, int xf, int yf);
 char far *~restorevideowin~  (char far *s, int xi, int yi, int xf, int yf);
 char far *~savevideow~       (char far *s);
 char far *~restorevideow~    (char far *s);

 Remark: savevideo, restorevideo, savevideowin, restorevideowin, savevideow
  and restorevideow are macros if ~CRT_FULL~ is defined before the line.
   #include <CRT.H>


%DECLARATION OF GLOBAL VARIABLES:

 int ~vmode_x~;
 int ~vmode_y~;
 int ~vmode_mode~;
 int ~crt_direct~;
 int ~crt_page~;
 int ~crtwin_just~;
 struct crtwin ~crtwin_dta~;
 char far *~video_addr~;
 const char ~crtframe_mat~[];
 const char ~mkline_mat~[];
 int ~changechar_height~;
 int ~changechar_func~;
 int ~changechar_blk~;
 int ~crt_EVGA_addr~;


%GENERAL DESCRIPTION OF ARGUMENTS:

 x,y   => Start position, or the position where a character or attribute is
          read or written. Where: x=> column; y=> row (or line).
           Remark: The upper left corner is the position (0,0) for all functions
           declared in CRT.H
 chr,c => character.
 color => color.
 s     => string to be outputted or buffer for ...video... or ...crt...
 xi,yi => Start position (upper left corner)
 xf,yf => End position (lower right corner)
 (for other variables see functions helps)

% Return to:
    ~Introduction~   ~CRT.H~

:CRT.H
%  ▄▄▄▄▄▄▄
%   CRT.H
%  ▀▀▀▀▀▀▀
%  Functions
%  ▀▀▀▀▀▀▀▀▀
    ~barcolor~        ~biosprintc~      ~changechar~      ~changecharg~
    ~changecolor~     ~crt_detect~      ~crt_getxy~       ~crt_gotoxy~
    ~crt_init~        ~crtframe~        ~crtframew~       ~crtwindow~
    ~fillbar~         ~fillbarw~        ~fillbox~         ~fillboxw~
    ~fillscr~         ~getbordercolor~  ~getcrtchar~      ~getcrtcolor~
    ~getcrtmode~      ~getcursorsh~     ~getdacpgstate~   ~getdacreg~
    ~getpalreg~       ~janela~          ~janelad~         ~linha_hor~
    ~linha_ver~       ~linhad_hor~      ~linhad_ver~      ~mkline~
    ~mkline_aux~      ~moldura~         ~moldurad~        ~molduradw~
    ~molduraw~        ~printc~          ~printcn~         ~printct~
    ~prints~          ~printsf~         ~printsj~         ~printsjc~
    ~printsjcf~       ~printsjf~        ~printsn~         ~printsnf~
    ~printtext~       ~printtextf~      ~printx~          ~printxf~
    ~printxy~         ~printxyf~        ~restorecrt~      ~restorecrtw~
    ~restorecrtwin~   ~restorevideo~    ~restorevideow~   ~restorevideowin~
    ~savecrt~         ~savecrtw~        ~savecrtwin~      ~savevideo~
    ~savevideow~      ~savevideowin~    ~setbordercolor~  ~setchrboxwidth~
    ~setcrtmode~      ~setcrtpage~      ~setcrtwin~       ~setcursorsh~
    ~setdacpage~      ~setdacpgmode~    ~setdacreg~       ~setpalreg~
    ~settextblink~    ~videomode~

%  Constants, data types, and global variables
%  ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ~BKCOLOR~           ~CHANGCHR_NORM~     ~CHANGCHR_RECALC~
    ~CRT_FULL~          ~CRT_COLORS~        ~DACPAGE_16~
    ~DACPAGE_64~        ~RESTORECRT·~       ~RESTORECRTWIN·~
    ~SAVECRT·~          ~SAVECRTWIN·~       ~TEXTBLINK~

    ~crt_EVGA_addr~     ~changechar_height~ ~changechar_func~
    ~changechar_blk~    ~crt_direct~        ~crt_page~
    ~crtframe_mat~      ~crtwin~            ~crtwin_dta~
    ~crtwin_inp~        ~crtwin_just~       ~mkline_mat~
    ~video_addr~        ~vmode_mode~        ~vmode_x~
    ~vmode_y~

%  See Also
%  ▀▀▀▀▀▀▀▀
    ~List of all Header files~   ~Pre-compiled headers~   CRT.H file

%  Return to:
    ~Introduction~

:CRT_COLORS:BKCOLOR:TEXTBLINK
%   CRT_COLORS                         <CRT.H>
%  ▀▀▀▀▀▀▀▀▀▀▀▀
    Enumerated Constants for color.

    CRT_COLORS is equivalent to ~COLORS~

    Constant     │Value
   ══════════════╪═════
    BLACK        │  0
    BLUE         │  1
    GREEN        │  2
    CYAN         │  3
    RED          │  4
    MAGENTA      │  5
    BROWN        │  6
    LIGHTGRAY    │  7
    DARKGRAY     │  8
    LIGHTBLUE    │  9
    LIGHTGREEN   │ 10
    LIGHTCYAN    │ 11
    LIGHTRED     │ 12
    LIGHTMAGENTA │ 13
    YELLOW       │ 14
    WHITE        │ 15
   ──────────────┼─────
    BKCOLOR      │ 16 *
   ──────────────┼─────
    TEXTBLINK    │128 **

   Colors 0 through 15 are foreground colors if alone, but you can set a
 foreground and background color by multiplying the desired background color
 (0 - 15) by BKCOLOR and adding it to the desired foreground color.
   * BKCOLOR is only defined in CRT.H
   ** TEXTBLINK is the same of ~BLINK~

   These colors can be redefined in an EGA/VGA/SVGA adapter with ~setpalreg~
 or ~setdacreg~ (VGA/SVGA)

% See Also:
    ~Appendix B~

:vmode_x:vmode_y
% vmode_x and vmode_y                  <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    vmode_x and vmode_y tells the VIDEO HANDLING FUNCTIONS (prototyped in CRT.H
  the screen shape (number of columns and rows).

   ■ vmode_x stores the expected number of columns by CRT functions.
   ■ vmode_y stores the expected number of rows by CRT functions.

% Declaration:
   ■ int vmode_x;
   ■ int vmode_y;

% Remarks:
    These global variables defines the number of rows and columns of current
  text mode (or text mode that should be selected).

    The default values for vmode_x and vmode_y are: 80, 25, respectively.

    Note that vmode_x and vmode_y doesn't store the actual number of rows
  and columns of the current text mode. They store the expected number of
  rows and columns, delimiting the area that can be used by the functions
  declared in CRT.H, so if the value of vmode_x or vmode_y is different from
  the actual number of columns or rows, these functions will write and read
  at unexpected position, which can be used to obtain interesting effects,
  without need of extra logic. * * * Do some tests with a little different
  values for vmode_x and vmode_y than normal. They can be changed to any value,
  but beware the danger of loosing important data with very big values.

    Also remember that very big values may cause segment overflow. If this
  occurs a character that was expected to be written in another text video
  page, or at the bottom of current page (if page has >100 lines) will be
  written closer to the top.

    To update vmode_x and vmode_y to actual number of columns and lines on
  screen use ~crt_detect~ or ~crt_init~.

    All functions declared in CRT.H consider the upper left corner as being
  position (0,0), the same as BIOS. Most C and C++ functions consider the upper
  left corner as being position (1,1).

% See Also:
    All ~global variables~ list             ~crt_direct~    ~video_addr~

:vmode_mode
%  vmode_mode                          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    Defines current (or expected) video mode.

% Declaration:
    int vmode_mode;

% Remarks:
    vmode_mode is used to tell the programmer the current video mode. The
  default value is 3. Notice that not always the value stored in vmode_mode
  is the actual current mode. To update it to current video mode value
  use one of the folowwing:
    ~setcrtmode~, ~getcrtmode~, ~crt_detect~ or ~crt_init~ call.

% See also:
    ~crt_page~   ~crt_direct~   ~video_addr~   ~vmode_x~   ~vmode_y~

:crt_direct
%  crt_direct                          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
  Controls video access.

% Declaration:
    int crt_direct;

% Remarks:
   crt_direct defines if the video access is done directly to video RAM
   (video map) or via BIOS calls

  Value│ Meaning
  ═════╪══════════════════════════════════════════════
    0  │ (Default) Defines direct video RAM access
    1  │ Defines access via BIOS calls (int 10h)
    >1 │ Same as value 1, but are reserved for future versions

    If you set crt_direct to direct video RAM access (default), your system's
  video hardware must be compatible with IBM display adapters, and text mode
  must be set, otherwise the video handling functions won't work properly.
  The advantage of this mode is that functions are executed extremely fast.
  (Tests done under Windows 3.11/95 have shown that these functions work fine
  in a DOS-PROMPT box even if crt_direct==0)

    If you set crt_direct to access via BIOS, these functions will work in any
  IBM-BIOS compatible system and even in graphics mode, however they will be
  executed much slower (hundreds time slower!).

    To detect if current video mode is a text mode or a graphics mode, use
  crt_detect or crt_init. These functions automatically updates crt_direct
  according to current video mode. If current video mode is a text mode,
  crt_direct=0. If current mode is a graphics mode, crt_direct=1. It works
  in almost every cases.

    If you use graphics mode or if you need it to work in any video hardware,
  then you might need to change crt_direct value to 1, for video handling
  functions work properly. (except for few functions that use always
  BIOS calls), because with crt_direct==0, these function outputs/reads only
  from text video RAM, which is not active and possibly disabled when graphics
  mode is selected.

    The access via BIOS calls has been provided to increase portability. (this
  allows these functions working in almost any video hardware and even in
  graph mode, but note that it isn't selected by default, as it is very slow.

  IMPORTANT: Although any other value than zero or 1 will have the same effect
  as 1, it's not advisable to use any other value than specified, as them are
  reserved for future versions.

% See Also:
    All ~global variables~ list     ~crt_detect~   ~crt_init~   ~video_addr~

:crt_page
%  crt_page                            <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀
  Selects the video page which will be used when the functions write or
  read via BIOS.

% Declaration:
    int crt_page;

% Remarks:
    crt_page selects the video page that will be used by the functions, when
  they use BIOS calls.
    The default value is 0.

  To update crt_page to active display page number, use ~getcrtmode~,
  ~crt_detect~ or ~crt_init~.

% See Also:
    All ~global variables~ list     ~vmode_mode~  ~crt_direct~  ~video_addr~


:video_addr
%  video_addr                          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
  Defines text video RAM (video map) base address.

% Declaration:
    char far *video_addr;

    video_addr defines the memory address where begins the video map or video
  RAM in text mode. Is the memory address where is written or read the
  character at position (0,0), when crt_direct==0. The default value is
  B800:0000h

% Remarks:
    video_addr can be changed to different values if the video RAM starts at a
  different memory address, or if the programmer desires to obtain interesting
  effects.
    When changing video_addr to another value left a low OFFSET value to avoid
  the possibility of segment overflow that will cause the data to be read or
  written in a smaller memory address position than expected. This is specially
  dangerous if that memory position is being used by another program. Another
  solution would be to use huge pointers.
    Beware of important data loss if video_addr points to an memory address
  used by a program or operating system.

    The functions that writes at video RAM have an internal protection that
  prevents them from writing outside the area that is delimited by video_addr,
  vmode_x and vmode_y, which means that they can only write into a memory area
  that goes from (video_addr) thru (video_addr + 2 * vmode_x * vmode_y - 1).
  To exceed this limit, increase the value of vmode_y or decrease the
  video_addr segment.
    video_addr is used only when crt_direct==0.

    To update video_addr to current video page start address use crt_detect or
  crt_init.

    video_addr is also changed by a setcrtpage call

% See Also:
    All ~global variables~ list        ~vmode_x~  ~vmode_y~  ~crt_direct~
      ~far~ pointers      ~huge~ pointers  ~crt_detect~  ~crt_init~

:crt_EVGA_addr
%  crt_EVGA_addr                       <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
  crt_EVGA_addr determines EGA/VGA+ adapter base I/O port address.

% Declaration:
    int crt_EVGA_addr;

% Remarks:
   crt_EVGA_addr is used by some VIDEO HANDLING FUNCTIONS routines that
 access directly the video adapter through I/O ports.

   Change the value of crt_EVGA according to the video adapter you are going
 to use:

   Value │ Video adapter
  ═══════╪═════════════════════════════════════
   3C0h  │ (Default) primary EGA/VGA+
   2C0h  │ alternate EGA/VGA+

   Beware of hardware installed at 2C0h.

% See Also:
    All ~global variables~ list


:crtframe_mat:mkline_mat
%  crtframe_mat and mkline_mat         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

  ■ crtframe_mat is an array used by ~crtframe~.
  ■ mkline_mat is an array used by ~mkline_aux~ and ~mkline~.

% Declaration:
  ■ const char crtframe_mat[];
  ■ const char mkline_mat[];

% Remarks:

    The programmer will be able to read characters from these arrays, but
  won't be able to change them, because they are declared in CRT.H as
  constants. To change them remove the "const" keyword (in CRT.H) before
  their declaration.
    They are:

    ■ const char crtframe_mat[]="┌─┐│┘─└│╔═╗║╝═╚║▐▀▌▌▌▄▐▐████████";

    ■ const char mkline_mat[]="\
    ─   ═\
  ┌┐┬ ╒╕╤\
  └┘┴ ╘╛╧\
 │├┤┼│╞╡╪\
    ─   ═\
  ╓╖╥ ╔╗╦\
  ╙╜╨ ╚╝╩\
 ║╟╢╫║╠╣╬\
 ";

  Note that in mkline_mat:
  The blank spaces represents character FFh.
  Each row has eight elements. The first is mkline_mat[0], and the last is
  mkline_mat[63].

% See Also:
    All ~global variables~ list

:crtwin_just
%  crtwin_just                         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀
  Controls the text justification for ~printsj~... functions, inside active
  text box.

% Declaration:
    int crtwin_just;

% Remarks:
    The default value is 1 (CENTER_TEXT)
    You may also use the symbolic constants defined by text_just enum declared
  in GRAPHICS.H

        Constant    │Value│ Meaning
       ═════════════╪═════╪═════════════════════
        LEFT_TEXT   │  0  │ Left-justify text
        CENTER_TEXT │  1  │ Center text
        RIGHT_TEXT  │  2  │ Right-justify text

    crtwin_just only affects ~printsj~, ~printsjc~, ~printsjf~ and ~printsjcf~
  and is affected by ~crt_init~.

% See Also:
    All ~global variables~ list     ~text_just~

:crtwin_dta
%  crtwin_dta                          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    A ~crtwin~ struct that defines the active text box (text window) (that is
  used by printsj and crtwindow) coordinates. Note that this active text
  window has no relationship with ~window~ function defined in ~CONIO.H~.
    It's value may be loaded from another crtwin struct or via ~setcrtwin~
  macro.

% Default values are:
       crtwin_dta.left=-1      crtwin_dta.right=80
       crtwin_dta.top=-1     crtwin_dta.bottom=25

% See Also:
    All ~global variables~ list      ~setcrtwin~

:crtwin
%  crtwin                              <~CRT.H~>
% ▀▀▀▀▀▀▀▀
    Structure type used to store text windows or text box coordinates.

    struct crtwin
     {
       int left;
       int top;
       int right;
       int bottom;
     };

% See Also:
    ~crtwin_dta~

:crtwin_inp
%  crtwin_inp                          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    The structure of the values passed to ~crtwindow~ function call.

    struct crtwin_inp
     {
       char *title; //Text Box Title (if title==NULL doesn't print title)
       int tcolor; //Title color
       int fchr;   //character used to fill window internal area
       int fcolor; //internal window area color
       int bcolor; //box border color
       int btype;  //box border type, same as crtframe
     };

% See Also:
   ~crtwin~     ~crtwindow~

:crt_detect:crt_init
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌crt_detect and crt_init▐            <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ crt_detect      Detects current video mode, number of columns, rows, video
                      page, current page start address,...
    ■ crt_init        Calls crt_detect and updates crtwin_dta coordinates and
                      crtwin_just to CENTER_TEXT.

% Declaration:
    ■ void crt_detect (int mode);
    ■ void crt_init   (int mode);

% Remarks:
    crt_detect detects current video mode, active display page, number of
  screen columns and rows. It also detects active display page base address
  and if current mode is a text or graphics mode.

    After a call to crt_detect, CRT.H global variables are updated as follow:
  ~vmode_mode~ = current video mode
  ~crt_page~   = active video page
  ~crt_direct~ = 0 if current mode is a text mode;
             = 1 if current mode is a graphics mode
  ~video_addr~ = active video page base address(if current mode is a text mode)
  ~vmode_x~    = number of columns of current mode
  ~vmode_y~    = number of rows on screen

    crt_init calls crt_detect and after updates ~crtwin_dta~ and ~crtwin_just~
  as follows:

  crtwin_dta.left   = -1
  crtwin_dta.top    = -1
  crtwin_dta.right  = vmode_x
  crtwin_dta.bottom = vmode_y
  crtwin_just       = 1 (CENTER_TEXT)

    The main reason to call crt_detect directly is to keep crtwin_dta
  coordinates and crtwin_just unchanged and update CRT.H global variables
  listed above.

    mode specifies the system video adapter, according to the table below

      Value  │ Video adapter
    ═════════╪═════════════════════════════════
     1       │ CGA
     2       │ MCGA *
     3,4,5   │ EGA  *
     9       │ VGA, SVGA or better

   * Not tested.

    To detect your video adapter you may try ~detectgraph~ declared in
  ~GRAPHICS.H~. Compilers earlier than Turbo C 3.0 may have enhanced versions
  of detectgraph that may return other values for a SVGA+ adapter. Unhapply
  I don't have these new versions.

    mode is the same as enum ~graphics_drivers~ (declared in GRAPHICS.H) for
  values 1(CGA) 2 (MCGA) 3,4,5 (EGA) and 9(VGA or better).

    crt_detect reads video hardware to detect if video is in text mode or
  in graphics mode.

    crt_detect is also affected by ~crt_EVGA_addr~

    Important: I can't guarantee that crt_detect and crt_init will detect
  the above CRT.H global variables correctly in a adapter other than CGA
  or color VGA/SVGA.

% Return Value:
    Both functions return nothing.

% Portability:
    See ~appendix A~

% Hardware Compatibility:
    CGA, MCGA, EGA, VGA, SVGA and newer (tested only CGA and SVGA)

% See also:
    ~detectgraph~

% Example:

  Warning: Before running this example, check your video adapter type.
  If your adapter is not a color VGA (or SVGA or better), replace crt_detect/
  crt_init input argument by one of the following: CGA, MCGA, EGA.

 #include <CRT.H>
 #include <conio.h>

 #define CGA 1
 #define MCGA 2
 #define EGA 3
 #define VGA 9

 void main ()
  {
    //Messages
    char *msg[2]={"Text","Graphics"};
    char *msg2[2]={
       "Current page base address (video_addr)",
       "Value of video_addr (not changed)"};

    //Detects screen mode, number of columns, rows, etc
    //If your adapter is not VGA/SVGA replace crt_init/crt_detect parameter.
    //You may choose between calling crt_init or calling crt_detect,
    //setcrtwin and updating crtwin_just
    crt_init (VGA);  //or
    //crt_detect (VGA);
    //setcrtwin (-1,-1,vmode_x,vmode_y);
    //crtwin_just=1;

    //Paints the screen and displays the title
    fillscr ('░',0x19);
    fillbar (' ',2,4,60,16,0x17);
    printsj ("* * * CRT_DETECT/CRT_INIT EXAMPLE * * *",1,0x1E);

    //Displays a report after a call to crt_init
    printxf (5,5,0x1f,"Current video mode (vmode_mode) = %d (%.2X)h",
       vmode_mode,vmode_mode);
    printxf (5,7,0x1f,"Active display page (crt_page) = %d",crt_page);
    printxf (5,9,0x1f,"%s mode selected. (crt_direct = %d)",msg[crt_direct],
       crt_direct);
    printxf (5,11,0x1f,"%s = %Fp",msg2[crt_direct],video_addr);
    printxf (5,13,0x1f,"Number of columns (vmode_x) = %d",vmode_x);
    printxf (5,15,0x1f,"Number of rows (vmode_y) = %d",vmode_y);

    //Displays message to exit and pauses
    printsj (" - - - Hit any key to exit - - - ",vmode_y-1,0x9e);
    getch ();
  }

:videomode
% ▄▄▄▄▄▄▄▄▄▄▄
% ▌videomode▐                          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀
  Changes ~vmode_x~ and ~vmode_y~ to normally used values (commonly text mode
 number of rows and columns) (obsolete function)

% Declaration:
    void videomode (int newmode);

% Remarks:
    newmode changes global variables vmode_x and vmode_y to predefined values.
  These global variables defines the number of rows and columns of current text
  mode (or text mode that should be selected). The predefined values are the
  most common number of rows and columns of text modes, they are listed in the
  table below:

                   │  (expected text mode size)
       newmode:    │  vmode_y     vmode_x
  ═════════════════╪═══════════════════════════════════════════
    -1 (LASTMODE)  │  (last mode values)   (default=25 X 80)
    0  (BW40)      │     25   X   40
    1  (C40)       │     25   X   40
    2  (BW80)      │     25   X   80
    3  (C80)       │     25   X   80       (default)
    7  (MONO)      │     25   X   80
    24             │     43   X   40
    32             │     43   X   80
    48             │     50   X   40
    64 (C4350)     │     50   X   80

  (The values in parenthesis refer to text_modes enum defined in CONIO.H)

    It was at first designed to be used with textmode, using the same value.
  textmode selects video mode and videomode updates vmode_x and vmode_y. As
  we can see in the table above, videomode is not perfect, for example
  (C4350) may select 50 or 43 columns in textmode, but only 50 in videomode.
  With creation of crt_detect, there's no need to use videomode anymore.

  Note that: The videomode function has no effect in current text mode and
  color display, it changes only vmode_x and vmode_y.

  IMPORTANT: As it is an obsolete function, it might not exist in future
  versions. If it does it will probably be enhanced or have another
  functionality.

% Return Value:
    None.

% Hardware Compatibility:
    modes 0,1,2,3,7 => CGA,EGA,VGA,SVGA,(mono?)
    modes 24,32 => EGA (works with some limitations on VGA/SVGA)
    modes 48,64 => VGA/SVGA (EGA?)
    See also ~Appendix A~

% See also:
  ~crt_detect~   ~textmode~

% Example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    textmode (3);
    fillscr ('░',0x19);
    prints ("Default mode: 25 rows x 80 columns",20,1,0x1f);
    getch ();

    videomode (1);
    fillscr ('░',0x2a);
    prints ("Incorrect use of Videomode",0,0,0x2f);
    prints ("25 X 40 screen size for functions",5,2,0x2f);
    prints ("But in 25 X 80 text mode",10,3,0x2f);//note the interesting effect
    getch ();

    textmode (1);
    videomode (1);
    fillscr ('░',0x2a);
    prints ("Right use of Videomode",0,0,0x2f);
    prints ("25 X 40 screen size for functions",5,1,0x2f);
    prints ("on 25 X 40 text mode",10,3,0x2f);
    //with vmode_x and vmode_y corresponding to real values, there's no problem.
    getch ();

    textmode (64); //if your monitor is CGA this mode change is not effective
                   //I don't know if it's dangerous to try this in
                   //monitors older than EGA.

    videomode (48); //if your monitor is EGA use videomode(24) instead
    fillscr ('░',0x19);
    prints ("Videomode in 50 X 40 text mode",5,1,0x1f);
    getch ();

    textmode (3);
    textmode (C4350); //if your monitor is CGA this mode change is not effective
                      //I don't know if it's dangerous to try this in
                      //monitors older than EGA.

    videomode (C4350); //if your monitor is EGA use videomode(32) instead
    fillscr ('▒',0x19);
    prints ("High resolution mode (50 X 80)",25,1,0x1f);
    getch ();

    fillscr (' ',7);//clears the screen
    crt_gotoxy(0,0);
  }

:setcrtmode:getcrtmode
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setcrtmode and getcrtmode▐          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
   ■ setcrtmode changes current video mode and calls getcrtmode
   ■ getcrtmode gets current video mode updating vmode_x and crt_page

% Declaration:
   ■ void setcrtmode (int mode);
   ■ int getcrtmode (void);

% Remarks:
    setcrtmode calls getcrtmode after changing video mode, which stores the
 selected video mode in ~vmode_mode~.
    getcrtmode loads vmode_x with number of columns, ~crt_page~ with current
 video page and vmode_mode with current video mode. It uses INT 10h/AH=0Fh
    getcrtmode doesn't update ~vmode_y~(screen height). To update vmode_y
 use ~crt_detect~. You may try also ~gettextinfo~.

% Return Value:
    ■ setcrtmode:  none
    ■ getcrtmode:  current video mode (also stored in vmode_mode);

% Hardware Compatibility:
    CGA,EGA,PS,VGA,SVGA and newer (tested only CGA and SVGA)

% See also:
    ~textmode~    ~crt_detect~    ~crt_init~

% Example:

 #include <CRT.H>
 #include <conio.h>
 #include <stdio.h>

 void main ()
  {
    char msg[]="\nscreen width=%d\nscreen height=%d\ncurrent video page=%d\
 \ncurrent video mode=%.2Xh\n"; //message to be displayed
    getcrtmode(); //get current video mode and updates vmode_x and crt_page
                  //doesn't update vmode_y => vmode_y might be incorrect
    printf (msg,vmode_x,vmode_y, crt_page, vmode_mode); //display message
    getch ();
    setcrtmode(1); //set video mode 1.
    printf (msg,vmode_x,vmode_y, crt_page, vmode_mode);
    getch ();
    setcrtmode(7);
    printf (msg,vmode_x,vmode_y, crt_page, vmode_mode);
    getch();
    setcrtmode(3);
    printf (msg,vmode_x,vmode_y, crt_page, vmode_mode);
    getch ();
  }

:setcrtpage
% ▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setcrtpage▐                         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    Selects video active display page.

% Declaration:
    void setcrtpage (int page);

% Remarks:
    After selecting the active display page, setcrtpage calls ~getcrtmode~ to
 update ~vmode_x~, ~vmode_mode~ and ~crt_page~ to their actual values. After
 this setcrtpage updates ~video_addr~ to starting address of current page.
 crt_page stores the current video page.

% Return value:
    None.

% Portability:
    See ~Appendix A~.

% Hardware Compatibility:
    CGA,EGA,PS,VGA,SVGA (tested only in CGA/SVGA)
    May work in monochrome monitors (not tested)
    May not work in PCjunior, Tandy 1000, Corona/Cordata BIOS v4.10+

% See also:
    ~getcrtmode~

% Examples:
    ~setcrtpage example~    ~Example 4~

:setcrtpage example
%   setcrtpage example
%  ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

 #include <stdio.h>
 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int c0,a0;
    char page_cor[4]={ 0x1c, 0x1e, 0x1f, 0x1b}; //colors for each page

    setcrtmode (3); //changes video mode

  /*Here the user enters the text for each video page */
    for (c0=0;c0<4;c0++)
     {
       setcrtpage(c0); //select video page given by c0

       //selects background color and text color of each page according to
       //page_cor
       fillscr (' ',page_cor[c0]);

       //writes a message to the user reporting the current video page
       printsf (20,1,0x1f,"Current video page = %d",crt_page);
       printsf (10,2,0x1f,"Write below the text for page %d. \
 To continue hit ESC key",crt_page);

       //reads the text written by the user until user hits ESC key
       crt_gotoxy(0,3);
       do
        {
          a0=getch();
          if (a0==0x0d)
             putchar(0x0a);
          putchar(a0);
        }
        while(a0!=0x1b);
     }

  /*Here each page is displayed */
    for (c0=0;c0<4;c0++)
     {
       setcrtpage(c0);

       //reuses the messages written before, replacing some words
       prints ("  The text you wrote",10,2,0x1f);
       prints ("any",59,2,0x1f);

       getch (); //waits until user hits any key
     }
    setcrtpage(0); //Select page 0 as active page (default)
    fillscr (' ',0x07); //clears the screen
  }

:crt_gotoxy:crt_getxy
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌crt_gotoxy and crt_getxy▐           <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
   ■ crt_gotoxy changes current cursor position.
   ■ crt_getxy gets current cursor position.

% Declaration:
    void crt_gotoxy (int x,  int y );
    int  crt_getxy  (int *x, int *y);

% Remarks:
    crt_gotoxy and crt_getxy works in video page selected by ~crt_page~.
    crt_gotoxy moves the cursor to position (x,y), where "x" indicates the
  column and "y" indicates the row, where (0,0) is the upper left corner. If
  argument values are incorrect, the behavior will depend on BIOS type.
    crt_getxy may return the current cursor position in two ways. The first is
  by the contents of *x pointer and *y pointer, where *x=column and *y=row.
  The second is by an integer value returned by this function, that is given
  by (row * 100h + column (DX register)). crt_getxy uses INT 10h/AH=03h.

% Return Value:
   ■ crt_gotoxy:   none
   ■ crt_getxy:    row*100h + column (DX register from INT 10h/AH=03h)

% Hardware Compatibility:
    All video adapters. (or almost all of them)

% See also:
    ~gotoxy~   ~wherex~   ~wherey~

% Example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int x, y;
    int x0, y0, z;
    //clears the screen
    fillscr (' ',0x07);
    //saves current cursor position in x, y and z.
    z=crt_getxy(&x0,&y0);
    //outputs current position
    printsf (x0%10,y0%10,0x1f,"Current cursor position = (%d,%d)",x0,y0);
    printsf (x0%10,y0%10+1,0x1f,"Value returned by crt_getxy = %.4Xh",z);
    getch ();
    //moves the cursor to a new position
    crt_gotoxy (x0%10+31,y0%20+2);
    crt_getxy(&x,&y);
    printsf (x%10,y%10+2,0x1f,"New cursor position = (%d,%d) => ",x,y);
    getch ();
    //restores initial position
    crt_gotoxy (x0,y0);
    printsf (x0%10,y0%10+3,0x1f,"Old cursor position = (%d,%d)",x0,y0);
    getch ();
  }


:getcrtchar:getcrtcolor
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌getcrtchar and getcrtcolor▐         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
   ■ getcrtchar gets the character from position (x,y).
   ■ getcrtcolor gets the color from position (x,y).

% Declaration:
   ■ int   getcrtchar  (int x, int y);
   ■ int   getcrtcolor (int x, int y);

% Remarks:

    These functions uses direct VIDEO RAM access when crt_direct==0,
  otherwise they use access via BIOS calls (INT 10h/AH=8).
    In graphics mode, crt_direct must be different than 0 (zero), and
  getcrtchar and getcrtcolor may not work properly. Documentation about
  INT 10h/AH=8 says that in graphics mode only characters drawn with
  white foreground pixels are matched by the pattern-comparison routine.

% Return Value:
   On success: got character and color.
   On error: random value (for example, if you gave coordinates outside the
   range of the current screen mode, or if BIOS calls fail)

% Examples:
    ~Example 1~

%   getcrtchar and getcrtcolor example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int a0,a1;
    a0=getcrtchar(0,0); //getcrtchar reads the char from position (0,0)
    a1=getcrtcolor(0,0); //getcrtcolor gets the color from position (0,0)

    //the character and color found at position (0,0) are displayed
    printsf(0,2,15,"Character at position (0,0)='%c' ",a0);
    printsf(0,3,15,"Color at position (0,0)=%.2Xh ",a1);
    getch ();
  }

:biosprintc
% ▄▄▄▄▄▄▄▄▄▄▄▄
% ▌biosprintc▐                         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    outputs a character into screen via BIOS calls.

% Declaration:
    void biosprintc (int chr, int x, int y, int color, int func);

% Remarks:
    The function biosprintc is used by other functions to access the screen
  when ~crt_direct~ != 0, but it can also be used by the programmer.
    The argument "func" defines which BIOS function will be used. The only
  accepted values (as I know) are 09h or 0Ah, different values may let to
  unpredictable and likely disastrous results.
    crt_direct has no effect over biosprintc.
    values for "func":
       09h   => outputs character with color (both in text and
                graphics mode).
       0Ah   => Outputs character. In text mode writes only the character,
                keeping the color of position (x,y)
                In graphics mode draws character with color (just as when
                func==9).

    The argument "func" is the value of AH register in a call to INT 10h,
  which selects the video function that must be used. Other arguments are
  similar to printc arguments.
    If attribute bit 7 is set in <256-color graphics mode, character is XOR'ed
  onto screen.

% Return value:
    None.

% Hardware Compatibility:
    All PC video adapters. (at least most of them)

% See also:
    ~printc~   ~printcn~   ~changecolor~

% Example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    clrscr (); //clears the screen
    getch ();
    biosprintc ('A',2,2,0x1e,9);
       //sends character 'A' with color 1Eh (yellow with blue background)
    getch ();
    biosprintc ('B',2,3,0x1f,10);
       //sends character 'B'
       //On text mode, keeps the previous color at position. In graphics mode
       //outputs with color 1Fh
    getch ();
  }

:printcn:printc:changecolor
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌printcn, printc▐                    <~CRT.H~>
% ▌and changecolor▐
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
   ■ printcn outputs a character with no color onscreen.
   ■ printc  outputs a character with color onscreen.
   ■ changecolor changes the color of position (x,y).

% Declaration:
   ■ void  printcn     (int c, int x, int y           );
   ■ void  printc      (int c, int x, int y, int color);
   ■ void  changecolor (       int x, int y, int color);

% Remarks:
    printc, printcn and changecolor use video RAM access when ~crt_direct~==0,
  otherwise they use ~biosprintc~ (output via BIOS calls).

    With crt_direct==0 they work only in text mode and:
     - printcn outputs the character keeping the previous color.
     - printc outputs the character with color (attribute)
     - changecolor replaces the existing color (attribute) by a new one.

    With crt_direct!=0:
     - printcn calls biosprintc with color 0x07 and "func"=0x0a.
     - printc calls biosprintc with argument "func"=0x09.
     - changecolor gets the character from position and redraws it with a
       new color (using biosprintc).

% Return Value:
    none (for all them)

% Hardware Compatibility:
    All PC video adapters (or almost all of them)

% See Also:
    ~printct~   ~print...~ functions   ~printx~

% Examples:
    ~Example 1~

%   printcn, printc and changecolor example:

 #include <CRT.H>
 #include <conio.h>

 //Notice what happens at the upper left corner of the screen

 void main ()
  {
    fillscr (' ',0x07); //clears the screen
    getch ();
    printcn ('A',0,0); //writes character A onscreen at the upper left corner
    getch ();
    printc ('B',1,0,0x1e); //writes character B beside A character
    getch ();
    changecolor (0,0,0x21); //changes the color of A character
    getch ();
  }

:printct
% ▄▄▄▄▄▄▄▄▄
% ▌printct▐                            <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀
    Changes the character and color of position (x,y) or keeps old character
  and/or color according to type parameter.

% Declaration:
    void printct(int c, int x, int y, int color, unsigned int type);

% Remarks:
    printct is a generalization of ~printcn~, ~printc~ and ~changecolor~. It's
  output will depend on ~printct type~ parameter.

    printct (c,x,y,color,1) is equivalent to printcn
    printct (c,x,y,color,2) is equivalent to changecolor
    printct (c,x,y,color,3) is equivalent to printc

    To use printct in graphics mode, ~crt_direct~ must be different of
  zero. To detect if video is in text or graphics mode use ~crt_detect~.

% Return value:
    None.

% See also:
    ~fillbox~

% Example:
 //To run this example in graphics mode, set crt_direct to 1

 #include <CRT.H>

 void main ()
  {
    fillscr ('.',LIGHTBLUE);//fills the screen with '.' and color LIGHTBLUE

 //printct called with char. 'A' and color 2Eh at position (8,5) with type=0
    prints ("=> type = 0",10,5,0x07);
    printct('A',8,5,0x2e,0);

 //printct called with char. 'A' and color 2Eh at position (8,6) with type=1
    prints ("=> type = 1",10,6,0x07);
    printct('A',8,6,0x2e,1);

 //printct called with char. 'A' and color 2Eh at position (8,7) with type=2
    prints ("=> type = 2",10,7,0x07);
    printct('A',8,7,0x2e,2);

 //printct called with char. 'A' and color 2Eh at position (8,8) with type=3
    prints ("=> type = 3",10,8,0x07);
    printct('A',8,8,0x2e,3);
  }

:printct type
%   type argument of printct and fillbox
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄


 bitfields for type:

    ╔══╤══╤══╤══╤══╤══╤══╤══╤══╤══╤══╤══╤══╤══╦══╦══╗
    ║15│14│13│12│11│10│ 9│ 8│ 7│ 6│ 5│ 4│ 3│ 2║ 1║ 0║
    ╚══╧══╧══╧══╧══╧══╧══╧══╧══╧══╧══╧══╧══╧══╬══╬══╝
       bits 15-2 are reserved for future        │  │
    versions, although printct works with any   │  │
    value in these bits, they should be zero, to│  │
    enable compatibility with future versions   │  │
                                                │  │
    Color control bit ──────────────────────────┘  │
       0 = printct doesn't replace color in text   │
           mode. In some graphics mode color is 7h │
           (light gray)                            │
       1 = printct replaces the color of position  │
           (x,y) by (color)                        │
                                                   │
    Text control bit ──────────────────────────────┘
       0 = printct doesn't replace character in text mode.
           In graphics mode character is read from (x,y) position
           and rewritten. (character may not be the same, due to
           failure of BIOS routine that reads character from screen
           in graphics mode)


:printsn:prints:printxy:print...
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌printsn, prints and printxy▐        <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
   ■ printsn outputs a string into screen keeping the previous color of each
     position.
   ■ prints  outputs a string into screen with color.
   ■ printxy outputs a string into screen with color and user defined spacing
     between characters.

% Declaration:
   ■ void  printsn (char *s, int x, int y);
   ■ void  prints  (char *s, int x, int y, int color);
   ■ void  printxy (char *s, int x, int y, int dx, int dy, int color);

% Remarks:
    The start position is given by (x,y). prints and printsn outputs the
  string in horizontal, while printxy may output in any direction.

    prints and printxy use ~printc~ function, while printsn uses ~printcn~.

    In printxy, the dx and dy arguments defines the horizontal and vertical
  increments between characters, respectively. For example, if dx=-1 and dy=0,
  the string is displayed in backward direction.

% Return Value:
     None (all of them)

% Hardware Compatibility:
    Depends on ~printc~ and ~printcn~ compatibility.

% See also:
    ~printx~   ~printtext~   ~printsj~   ~printsjc~
    CRT.H ~print...f~ functions

% Examples:
    ~Example 1~

%   printsn, prints, and printxy example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    fillscr (' ',0x07); //clears the screen
    getch ();
    printsn("PRINTSN EXAMPLE",2,0); //outputs string without replacing
       //previous color
    getch ();
    prints("PRINTS EXAMPLE",2,1,0x1e); //outputs string in yellow with a blue
       //background
    getch ();
    printxy("READ THIS -< ELPMAXE YXTNIRP",60,2,-2,0,0x1f); //outputs string
       //in backward direction. The color is white with a blue background
    getch ();
  }

:printx
% ▄▄▄▄▄▄▄▄
% ▌printx▐                             <~CRT.H~>
% ▀▀▀▀▀▀▀▀
    Outputs a string into screen with special options possibilities.

% Declaration:
    void printx (char *s, int x, int y, int color);

% Remarks:
    This function allows you to output a hole text with different colors and
  justifying options with a single call.
    The string (s) is a null terminated buffer that contains the text to be
  outputted and instructions character to be interpreted. In fact this function
  has it's own instruction set.
    The arguments (x,y,color) loads only the initial values, that can be
  changed by some instructions inside the string.

  The printx's "instruction set" is: (sorted by "opcode")
    (05)h     => Outputs the third byte with the color defined by the second
                 byte.
    (ENQ)          Format => "... \5<color><character(3rd byte)> ..."

    (06)h     => Changes current color to color defined by next byte.
    (ACK)          Format => "... \6<color> ..."

    (07)h     => Emits a "beep" via DOS call.
    (BELL)         Format => "... \a ..." OR "... \7 ..."

    (08)h     => Non destructive backspace. If current position is left side,
    (BKSPACE)    returns to the end of upper line (row).
                   Format => "... \b ..." OR "... \10 ..."

    (09)h     => Non destructive Tab (default tab size = 8)
    (TAB)          Format => "... \t ..." OR "... \11 ..."

    (0A)h     => New line and "carriage return" to taboffset value. (default==0)
    (NF)         It has the same effect of \n in ...printf functions,
                 if taboffset==0. (taboffset is an internal variable)
                   Format => "... \n ..." OR "... \12 ..."

    (0B)h     => New line (character (0A)h function in printer)
    (VT)           Format => "... \v ..." OR "... \13 ..."

    (0C)h     => Goes to upper left corner (position (0,0)).
    (FF)           Format => "... \f ..." OR "... \14 ..."

    (0D)h     => Returns to left size with offset defined by (taboffset)
    (CR)         (default for taboffset == 0).
                   Format => "... \r ..." OR "... \15 ..."

    (0E)h     => Changes x value. (column where next character will be
                 outputted)
    (SO)           Format => "... \16<new column position> ..."

    (0F)h     => Changes y value. (row where next character will be outputted)
    (SI)           Format => "... \17<new row position> ..."

    (10)h     => Changes tab size (default size = 8).
                   Format => "... \20<new tab size> ..."

    (11)h     => Changes taboffset value (offset for TAB) (default = 0).
                   Format => "... \21<taboffset> ..."

    (12)h     => Increments x value (column).
                   Format => "... \22 ..."

    (13)h     => Decrements y value (row).
                   Format => "... \23 ..."

    (14)h     => Pauses until a key is available from keyboard, checking
                 ^C/^BREAK.
                  Uses DOS function INT 21h/AH=08h
                   Format => "... \24 ..."

    (15)h     => Pauses until a key is available from keyboard. ^C/^BREAK are
                 not checked.
                  Uses DOS function INT 21h/AH=07h
                   Format => "... \25 ..."

    (1B)h     => Allows to output special characters ("opcodes" as characters)
    (ESC)          Format => "... \33<char.> ..."


  IMPORTANT: Do not left a instruct character that requires any complement
  (instructions 05h, 06h, 0Eh, 0Fh 10h 11h 1Bh) being the last of the string,
  the reason is that printx will confuse the null terminating character (\0)
  (automatically appended at the end of each string by the compiler) as
  a complement. As result printx will write and process beyond the end of
  the string (if you are not lucky it will continue far beyond and you will
  need to wait for hours until it stops).

% Return Value:
    None.

% Portability:
    Requires DOS or DOS compatible O.S (such as WINDOWS, WINDOWS 95/98)
    See also ~appendix A~.

% Hardware Compatibility:
    Will depend most of function ~printc~.

% See Also:
    ~prints~  ~printxy~   ~printtext~   ~printsj~   ~printsjc~
    CRT.H ~print...f~ functions.

% Example:
    ~printx example~

:printx example
%   printx example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
 //THIS IS THE STRING CONTAINING THE TEXT TO BE OUTPUTTED. THE SPECIAL EFFECTS
 //ARE OBTAINED VIA SPECIAL CHARACTERS (IN FACT PRINTX "OPCODES") For example
 //\n is an "instruction opcode" with the same function as \n in printf
    int a0;
    char sentence []= //\24 is the pause character, byte or "opcode"
 "* * * printx example * * *\
 \16\5\17\4\6\36\
 Example of printx function.\
 \n\Outputting (sentence) string contents\n\
 Hit any key to continue\24\
 \
 \6\x1f new color \24\
 \
 temporary color at \"\5\x1c\C\"\n\24\
 \
 BEEP\a\a\a\24\
 \
 \b\b\b\bBKSPACE 4 times\24\
 \
 \t\tTabulation\24\
 \
 \n\n\nNew line and return to begin of line\24\
 \
 \v\New line without returning to it's begin\24\
 \
 \rreturn to begin of line\24\
 \
 \fgoes to upper left corner\24\
 \
 \16\30\17\20Moves to position (24,16) => (30,20)octal\n\24\
 \
 \
 Tab size = 3:\20\3\na\ta\ta\ta\ta\n\24\
 \
 Tab Offset = 1:\21\1\na\ta\ta\ta\ta\n\n\24\
 \
 \33\5 Special character.\24\
 Pauses checking ^C/^BREAK.\24\
 Pauses without checking ^C/^BREAK.\25\
 \
 \
 \16\20\17\27\6\x9e - - - THE END - HIT ANY KEY TO RETURN - - -\25\
 ";//here ends the string.

 //ONLY THIS IS THE PROGRAM ITSELF

    fillscr ('░',0x19); //fills the screen with character '░' and color 0x19

  //all that text is outputted via this function! This function does almost
    printx (sentence,27,1,0x1f); //everything in this program!

  /*This displays the contents of sentence string with no formatting.*/

    fillscr (' ',7); //clears the screen
    prints ("(sentence) string contents with no formatting :",16,0,0x0f);
    a0=printtext(sentence,0,2,0x07); //displays the text in raw format
    printsf (0,11,0x0e,"(sentence) string size = %d bytes",a0);
       //a0=number of bytes in sentence
    getch ();
  }

:printtext
% ▄▄▄▄▄▄▄▄▄▄▄
% ▌printtext▐                          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀
    Writes a string inside a box continuing in the next line if text doesn't
  fit in one line.

% Declaration:
    int printtext (char *s, int x, int y, int color);

% Remarks:
    printtext writes inside the box defined by ~crtwin_dta~ struct. It starts
  writing at position (x,y) in relation to (crtwin_dta.left+1,crtwin_dta.top+1)
  with color defined by color. When reaching the end of line (column
  crtwin_dta.right-1) it continues in the next line (starting at column
  crtwin_dta.left+1). When it reaches the end of the last line of the box
  (position (crtwin_dta.right-1,crtwin_bottom-1)) it stops.
    If one (or both) of the coordinates is negative, the call to printtext is
  ignored.

% Return value:
    number of bytes written.

% Portability:
    See ~Appendix A~.

% Hardware Compatibility:
    Depends on ~printc~

% See also:
    ~prints~   ~printx~   ~printsj~    ~printsjc~
    CRT.H ~print...f~ functions

% Examples:

 ~printtext example~   ~printx example~    ~Example 3~

:printtext example
%   printtext example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    fillscr (' ',0x07);
    printtext (
 "This is an example of printtext function. Notice that printtext continues in\
  the next line if text doesn't fit in one line. Text is outputted inside text\
  window defined by crtwin_dta",10,1,0x1f);
    getch();
  }

:printsj:printsjc
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌printsj and printsjc▐               <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■prinstj writes a string inside the current text box defined by
  ~crtwin_dta~ struct with justification defined by ~crtwin_just~.
    ■printsjc is a enhanced version of printsj that allows color change
  inside the text to be outputted.

% Declaration:
    ■ void printsj  (char *s, int y, int color);
    ■ void printsjc (char *s, int y, int color);

% Remarks:

    printsj and printsjc write the null terminated string (s) with color
  (color) (y+1) lines below the line defined by (crtwin_dta.top)
    If coordinates given by crtwin_dta are invalid, the call to printsj or
  printsjc is ignored.
    for (y) values greater than the box height or smaller than zero, y assumes
  any value between 0 and the box height or any of both values.
    if crtwin_just is not 0 nor 1 nor 2, the call to printsj or printsjc is
  ignored. (That means printsj or printsjc returns without doing anything.)

    printsjc allows you to output a hole text with different colors with a
  single call. The argument color gives the beginning color of the text.
    The string (s) is a null terminated string that contains the text to be
  outputted and "instructions" character to be interpreted. These characters
  constitute printsjc "instruction set" (kind of a subset of printx
  instruction set).
    The arguments (x,y,color) loads only the initial values, that can be
  changed by some instructions inside the string.

  The printsjc's "instruction set" is: (sorted by "opcode")
    (05)h     => Outputs the third byte with the color defined by the second
                 byte.
    (ENQ)          Format => "... \5<color><character(3rd byte)> ..."

    (06)h     => Changes current color to color defined by next byte.
    (ACK)          Format => "... \6<color> ..."

    (1B)h     => Allows to output special characters ("opcodes" as characters)
    (ESC)          Format => "... \33<char.> ..."


  IMPORTANT: Do not left a instruct character being the last of the string,
  the reason is that printsjc will confuse the null terminating character (\0)
  (automatically appended at the end of each string by the compiler) as a
  complement. As result printsjc will write and process beyond the end of the
  string (if you are not lucky it will continue far beyond and you will need
  to wait for some minutes until it stops (the screen will become a mess)).

    printsjc uses special color "instruction" characters to change the
  color inside the text.

  Both functions use function ~printc~.

% Return Value:
    ■ printsj:  none
    ■ printsjc: none

% Portability:
    See ~appendix A~.

% Hardware Compatibility:
    Depends on ~printc~ compatibility.

% See Also:
    ~printsn~   ~prints~   ~printxy~   ~printx~   ~printtext~
    CRT.H ~print...f~ functions

% Examples:
    ~printsj example~   ~printsjc example~   ~Example 3~

:printsj example
%   printsj example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <conio.h>
 #include <CRT.H>

 void main ()
  {
    fillscr (' ',0x17);
    printsj("* * * PRINTSJ EXAMPLE * * *",1,0x1f);

 //LEFT JUSTIFIED TEXT
    crtwin_just=0;
    printsj("LEFT JUSTIFIED TEXT => crtwin_just=0",4,0x1e);

 //CENTER JUSTIFIED TEXT
    crtwin_just=1;
    printsj("CENTER JUSTIFIED TEXT => crtwin_just=1",6,0x1a);

 //RIGHT JUSTIFIED TEXT
    crtwin_just=2;
    printsj("RIGHT JUSTIFIED TEXT => crtwin_just=2",8,0x1b);
    getch ();
  }

:printsjc example
%   printsjc example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    fillscr (' ',0x17);
    printsjc("* * * PRINTSJC EXAMPLE * * *",1,0x1f);

 //LEFT JUSTIFIED TEXT
    crtwin_just=0;
    printsjc("LEFT JUSTIFIED TEXT => crtwin_just=0",4,0x1e);

 //CENTER JUSTIFIED TEXT
    crtwin_just=1;
    printsjc("CENTER JUSTIFIED TEXT => crtwin_just=1",6,0x1a);

 //RIGHT JUSTIFIED TEXT
    crtwin_just=2;
    printsjc("RIGHT JUSTIFIED TEXT => crtwin_just=2",8,0x1b);

 //COLOR INSTRUCTIONS
    crtwin_just=1;
    printsjc("EACH\6\x1e WORD\6\x1f WITH \5\x1a\x41 \6\x1b\x44IFERENT\6\x19 \
 COLOR\6\x1d !!!",11,0x1c);
    printsjc("EXAMPLE OF \"INST.\" CHARS. New color at '\5\x1b\x43'. \
 New \6\x1e\x63olor. Special chars => \x1b\5 \x1b\6 \x1b\x1b",14,0x1f);
    getch ();
  }

:printsnf:printsf:printxyf:printxf:printtextf:printsjf:printsjcf:print...f
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌CRT.H print...f functions▐          <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
   ■ printsnf   sends formatted output to screen via printsn.
   ■ printsf    sends formatted output to screen via prints.
   ■ printxyf   sends formatted output to screen via printxy.
   ■ printxf    sends formatted output to screen via printx.
   ■ printtext  sends formatted output to screen via printtext.
   ■ printsjf   sends formatted output to screen via printsj.
   ■ printsjcf  sends formatted output to screen via printsjc.

% Declaration:
   ■ int  printsnf    (int x, int y,                            char *fmt,... );
   ■ int  printsf     (int x, int y,                 int color, char *fmt,... );
   ■ int  printxyf    (int x, int y, int dx, int dy, int color, char *fmt,... );
   ■ int  printxf     (int x, int y,                 int color, char *fmt,... );
   ■ int  printtextf  (int x, int y,                 int color, char *fmt,... );
   ■ int  printsjf    (       int y,                 int color, char *fmt,... );
   ■ int  printsjcf   (       int y,                 int color, char *fmt,... );

% Remarks:
    These functions uses ~vsprintf~ to create the formatted string to be
    displayed.
    The formatted string mustn't exceed the internal buffer size of these
    function. If the buffer is exceeded, unpredictable and likely disastrous
    results may occur. (see table below):

     Functions │ Internal Buffer size
    ═══════════╪══════════════════════
     printsnf  │ 256 bytes
     printsf   │ 256 bytes
     printxyf  │ 256 bytes
     printxf   │ 4096 bytes
     printxtext│ 4096 bytes
     printsjf  │ 256 bytes
     printsjcf │ 256 bytes

    For further information see ...~printf~ functions

% Return Value:
    ■ On success, the print...f functions return the number of bytes outputted
       by vsprintf in the internal string.
    ■ On error, these functions return EOF

% Portability:
    It will depend on vsprintf and print... (CRT.H) functions portability.
    See also ~Appendix A~

% See Also:
   vsprintf     CRT.H      va_arg       va_end   va_start

  print...f example:

    The print...f functions declared in CRT.H are used in a very similar manner
 as printf is used, except that they output the formatted string using print...
 functions declared in CRT.H. For example:
    char s[4096];
    .
    .
    .
    sprintf(s,fmt,...);
    printx(s,x,y,color);

 is equivalent to:
    .
    .
    .
    printxf(x,y,color,fmt,...);

% Example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int c0=8, c1=35, c2, c3, c4, c5, c6,c7;
    fillscr ('░',0x19);
    c2=printsnf(10,0,"%d * %d = %d",c0,c1,c0*c1);
    getch();
    c3=printsf(10,1,0x1f,"%d / %d = %d and %d %c %d = %d",c1,c0,c1/c0,c1,'%',
       c0,c1%c0);
    getch();
    c4=printxyf(20,3,2,0,0x1f,"c1='%c'=%d=%xh",c1,c1,c1);
    getch ();
    setcrtwin(12,8,60,16);
    moldurad(12,8,60,16,0x1e);
    fillbar (' ',13,9,59,15,0x1f);
    c5=printsjf(1,0x1f,"Current text box is (%d,%d),(%d,%d)",
       crtwin_dta.left,crtwin_dta.top,crtwin_dta.right,crtwin_dta.bottom);
    getch ();
    c6=printsjcf(2,0x1f,"Selecting \6%ccolor given by crtwin_dta.top",
       crtwin_dta.top);
    getch ();
    c7=printtextf (2,4,0x1f,"Printtextf example => crtwin_dta.bottom=%d \
 crtwin_dta.right=%d",crtwin_dta.bottom,crtwin_dta.right);
    getch ();
    printxf (0,18,0x1e,"printsnf returned %d\tprintsf  returned %d\
 \nprintxyf returned %d\tprintsjf returned %d\tprintsjcf returned %d\
 \nprinttext returned %d%c",c2,c3,c4,c5,c6,c7,0x15);
    // 0x15=='\x15' is pause "opcode" in printx (see printx)
  }


:fillscr
% ▄▄▄▄▄▄▄▄▄
% ▌fillscr▐                            <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀
    Fills the screen with character "c" and color "color".

% Declaration:
    void  fillscr (int c, int color);

% Remarks:
    As printc... functions the fillscr function uses only the memory area
  delimited by ~video_addr~, ~vmode_x~ and ~vmode_y~. For a properly work,
  vmode_x and vmode_y must be equal to actual number of columns and rows of
  current text mode, if it's not you may obtain interesting effects. It's not
  advisable to set vmode_x and vmode_y to higher values than 256 . The reason
  is that you may destroy important data stored above C800:0000h used by
  programs stored at high UMB's, when using fillscr. (Anyway I can't be liable
  for any sillyness you might do. So be careful)

    If ~crt_direct~==0 it access directly the video RAM, otherwise
  (crtdirect!=0) the access to video is done via biosprintc
  (no direct memory handling).

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% Hardware Compatibility:
    The same of ~printc~ function.

% See Also:
    ~fillbar~   ~barcolor~   ~fillbox~

% Example:

 #include <CRT.H>
 #include <conio.h>

 //Example for fillscr function
 //by Márcio Afonso Arimura Fialho

 void main ()
  {
    getch (); //shows the initial screen drawing.
    fillscr ('░',0x19); //fills the screen with character '░' and color 19h
                         //(light blue with a blue background)
    getch ();
    fillscr ('A',0x2e); //fills the screen with character 'A' and color 17h
                         //(yellow with a green background)
    getch ();
    fillscr ('░',0x9b); //fills the screen with character '░' and color 9Bh
                         //(blinking light cyan with a blue background)
    getch ();
    fillscr (' ',7); //clears the screen
  }

:barcolor
% ▄▄▄▄▄▄▄▄▄▄
% ▌barcolor▐                           <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀
    Replaces the color of a text window to color (color)

% Declaration:
    void barcolor (int xi, int yi, int xf, int yf, int color);

% Remarks:
    xi,yi are the upper left corner co-ordinates.
    xf,yf are the lower right corner co-ordinates.
    xi,yi,xf,yf can be also understood as the left, top, right, bottom sides
  co-ordinates of the window, respectively.

    This function has no relationship with ~window~ function.

  Uses function ~changecolor~.

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% Hardware Compatibility:
    Depends on ~changecolor~ compatibility.

% See also:
    ~fillscr~     ~fillbar~     ~fillbox~

% Example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    textmode (3);
    fillscr (' ',7);
    prints ("The color inside the box will change.",10,8,0x0f);
    moldura (20,10,40,16,0x07);
    fillbar ('A',21,11,39,15,0x07);
    getch ();
    prints ("has changed!",35,8,0x0f);
    barcolor (21,11,39,15,0x1e);
    getch ();
  }


:fillbar:fillbarw
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌fillbar and fillbarw▐               <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ fillbar fills a text window with the character "c" and color "color".
    ■ fillbarw fills a text window given by crtwin_dta with character "c" and
      color "color".

% Declaration:
    ■ void fillbar (int c, int xi, int yi, int xf, int yf, int color);
    ■ void fillbarw (int c, int color);

% Remarks:
    xi,yi are the upper left corner co-ordinates.
    xf,yf are the lower right corner co-ordinates.
    xi,yi,xf,yf can be also understood as the left, top, right, bottom sides
  co-ordinates of the window, respectively.

    fillbarw calls fillbar with:
       xi=crtwin_dta.left+1;   yi=crtwin_dta.top+1;
       xf=crtwin_dta.right-1;  yf=crtwin_dta.bottom-1;

    These functions have no relationship with ~window~ function.

  Use function ~printc~.

% Return Value: none.

% Portability:
    See ~Appendix A~.

% Hardware Compatibility:
    Depends on printc compatibility.

% See also:
    ~fillscr~     ~barcolor~     ~crtwin_dta~

% Examples:
    ~fillbar example~     ~fillbarw example~     ~Example 2~

:fillbar example
%   fillbar example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    textmode (3);
    fillscr (' ',7);
    prints ("There's a box:",10,8,0x0f);
    moldura (20,10,40,16,0x07);
    getch ();
    fillbar ('A',21,11,39,15,0x1e);
    prints ("That has been filled up by fillbar",10,18,0x0f);
    getch ();
  }

:fillbox:fillboxw
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌fillbox and fillboxw▐               <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ fillbox replaces the characters and colors of a text window or keeps old
      characters and/or colors according to type parameter.
    ■ fillboxw is similar to fillbox, but text window coordinates are given by
      ~crtwin_dta~.

% Declaration:
    ■ void fillbox  (int c, int xi, int yi, int xf, int yf,int color,int func);
    ■ void fillboxw (int c, int color, int func);

% Remarks:
    c is the character, color is the character color or attribute.
    xi,yi are the upper left corner co-ordinates.
    xf,yf are the lower right corner co-ordinates.
    xi,yi,xf,yf can be also understood as the left, top, right, bottom sides
  co-ordinates of the window, respectively.

    fillbox is a generalization of fillbar and barcolor functions. It's output
  will depend on func argument, which has the same functionality of
  ~printct type~ argument.

    fillboxw calls fillbox with:
       xi=crtwin_dta.left+1;   yi=crtwin_dta.top+1;
       xf=crtwin_dta.right-1;  yf=crtwin_dta.bottom-1;

    fillbox and fillboxw have no relationship with ~window~ function.

    fillbox uses function ~printct~.
    fillboxw uses function fillbox.

% Return Value: none.

% See Also:
    ~fillscr~     ~fillbar~     ~barcolor~

% Examples:
    ~fillbox example~   ~fillboxw example~

:fillbox example
%   fillbox example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>

 void main ()
  {

    fillscr ('.',0x09);//fills the screen with character '.' and color 09h
                       //(light blue with black background)

 //fillbox called with character 'A' and color 2Eh with type=0
    prints ("fillbox called with type = 0",7,3,0x07);
    fillbox ('A',10,5,30,10,0x2e,0);

 //fillbox called with character 'A' and color 2Eh with type=1
    prints ("fillbox called with type = 1",47,3,0x07);
    fillbox ('A',50,5,70,10,0x2e,1);

 //fillbox called with character 'A' and color 2Eh with type=2
    prints ("fillbox called with type = 2",7,13,0x07);
    fillbox ('A',10,15,30,20,0x2e,2);

 //fillbox called with character 'A' and color 2Eh with type=3
    prints ("fillbox called with type = 3",47,13,0x07);
    fillbox ('A',50,15,70,20,0x2e,3);
  }


:fillboxw example
%   fillboxw example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 //This example draws a text box filled with character '.' and color 19h
 //(light blue with blue background), and them calls fillboxw.
 //To test this example in other video modes than 80x25, use crt_detect(X)
 //where X is your video adapter (1=CGA,2=MCGA,3=EGA,9=VGA/SVGA).

 void main ()
  {
    int c0;

    //crt_detect (X);
    fillscr ('░',0x19); //fills the screen
    setcrtwin (20,7,60,17); //change text box/window coordinates
    molduradw (0x1f); //draws the text box border

    for (c0=0;c0<4;c0++)
     {
      //displays current type value and draws the box
       printsf (21,5,0x1e,"Before a call to fillbox with type = %d",c0);
       fillbarw ('.',0x19);
       getch ();
      //notice what fillboxw does according to type value
       prints (" After",21,5,0x1e); //fixes the message displayed on screen
       fillboxw ('A',0x1e,c0);
       getch ();
     }
  }

:crtframe:crtframew
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌crtframe and crtframew▐             <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ crtframe draws the border of a text box (frame) with selectable or user
  defined outline.
    ■ crtframew is similar to crtframe, but uses box coordinates given by
  crtwin_dta.

% Declaration:
    ■ void crtframe (int xi, int yi, int xf, int yf, int color,
      unsigned int type);
    ■ void crtframew (int color, unsigned int type);

% Remarks:
    (xi,yi) is the upper left corner of the box.
    (xf,yf) is the lower right corner of the box.

    The frame goes from (xi,yi) to (xf,yf).
    For a better understanding, xi,yi,xf,yf can be understood as the left, top,
  right, bottom sides coordinates of the frame, respectively.
    The "color" argument is the color which the border of the text box will be
  drawn.
    The "type" argument selects which outline type will be used. There are
  three predefined types, and a user defined type, that can be defined if
  type is greater than 255 (FFh).
    The predefined types are:
       type = 0 => text box with single outline. (moldura macro)
       type = 1 => text box with double outline. (moldurad macro)
       type = 2 => text box with bold outline.

    The user defined type can be selected either if type==3 or if type is
  greater than 255 or smaller than 0.
    If type==3 it draws the border with current user defined character, without
       replacing it. (default='█'= DBh)
    If type>=100h it replaces the current user defined character and draws the
       border with this new character. This character is obtained from the
       remainder of "type" divided by 100h (new character=type%256) (the 8
       least significant bits of "type").
    "type" values greater than 3 or smaller than 256 are reserved for future
    versions. If type is inside this interval, the call to crtframe will be
    ignored.
    The table below summarizes the frame types according to type argument:

        type  │~crtframe_mat~ │  frame
       value  │ characters  │  type
   ───────────┼─────────────┼─────────────
         0    │ 0  thru 7   │ pre-defined
         1    │ 8  thru 15  │ pre-defined
         2    │ 16 thru 23  │ pre-defined
         3    │ 24 thru 31  │ user defined (default = '█')
    3<type<256│    <none>   │ none (reserved for future versions)
        >256  │ 24 thru 31  │ least 8 significant bits of type/
              │             │ redefines user defined outline


    crtframe uses crtframe_mat buffer to draw the frames, so if you want
  redefine pre-defined frames, remove from CRT.H the const directive in front
  of crtframe_mat declaration. This will allow you to edit this buffer. Note
  that characters 24 thru 31 (the number refers to it's index in on
  crtframe_mat) are changed when crtframe is called with type greater than 255,
  and are all the same.

    crtframew calls crtframe with (xi,yi)=(crtwin_dta.left,crtwin_dta.top)
  and (xf,yf)=(crtwin_dta.right,crtwin_dta.bottom).

  If you wish you may use these crtframe and crtframew macros:
      ~moldura~         ~molduraw~
      ~moldurad~        ~molduradw~

  They use function ~printc~.

% Return Value:
    None. (for both functions)

% Portability:
    See ~Appendix A~

% See Also:
    ~mkline~

% Examples:
    ~crtframe example~      ~crtframew example~       ~Example 2~

:crtframe example
%   crtframe example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    fillscr (' ',0x07); //clears the screen
    printsj ("- - - Hit any key to see the examples - - -",24,0x8e);
    getch ();

  //Draws a text frame with single outline
    prints ("Type = 0",6,3,0x1f); //message
    crtframe (5,5,15,10,0x1a,0); //draws the frame
    getch (); //pause

  //Draws a text frame with double outline
    prints ("Type = 1",26,3,0x1f);
    crtframe (25,5,35,10,0x1b,1);
    getch();

  //The outline now is in bold
    prints ("Type = 2",46,3,0x1f);
    crtframe (45,5,55,10,0x1c,2);
    getch ();

  //Draws a text frame with user defined outline (by default='█' (DBh))
    prints ("Type = 3",66,3,0x1f);
    crtframe (65,5,75,10,0x1d,3);
    getch ();

  //Outline now is character A. Changes user defined outline.
    prints ("Type = 256+'A'",3,13,0x1f);
    crtframe (5,15,15,20,0x1e,'A'+0x100);
    getch ();

  //Draws a text frame with user defined outline (now ='A' (41h))
    prints ("Type = 3 (again)",22,13,0x1f);
    crtframe (25,15,35,20,0x1f,3);
    getch ();
  }

:crtframew example:fillbarw example
%  crtframew and fillbarw example
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    fillscr ('░',0x19);
    setcrtwin (10,5,30,15); //set crtwin_dta coordinates
    crtframew (0x1e,1); //draws the box frame
    getch ();
    fillbarw (' ',0x17); //fills the box internally
    getch ();
  }

:mkline_aux
% ▄▄▄▄▄▄▄▄▄▄▄▄
% ▌mkline_aux▐                         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    Performs frame characters auto replacement according to its arguments.
  It's ~mkline~'s replacement algorithm.

% Declaration:
    void  mkline_aux (int cnt, int var, unsigned int mode, int pos, int color);

% Remarks:
    The frame characters, as I will call are defined in mkline_mat buffer, and
  are these used to draw text box or text frames, as found in menus of programs
  like MS-DOS EDIT.
    mkline calls this function for any character to be analyzed and possibly
  replaced. mkline only manages the replacement.

    If the character found at position where the replacement will be done
  isn't in ~mkline_mat~ or if it is FFh, pos arguments is set internally to 3
  and it performs complete replacement (as drawing a line).

  arguments

    Arg.  │ What it is?, What it does?
  ════════╪═══════════════════════════════════════════════════════════════════
   cnt    │  It's the co-ordinate that remains constant in successive calls by
          │ mkline (may be either x or y)
   var    │  It's the co-ordinate that is incremented in each call by mkline.
          │ if (cnt==x var==y) if (cnt==y var==x)
   mode   │  Indicates the kind of line to be draw (outline and orientation)
   pos    │  Indicates in which position the replacement is going to be done
          │ (if it's going to be done at the beginning, at the middle, or at
          │ the end of line draw by mkline).

    The cnt and var arguments have the same meaning in mkline function, they
  define the position where the replacement occurs.

   mode value   │ use and operation. (by with mkline)
  ══════════════╪══════════════════════════════════════════
    0           │horizontal line drawing. Single outline
                │y=cnt, x=var.
  ──────────────┼──────────────────────────────────────────
    1           │vertical line drawing. Single outline
                │x=cnt, y=var.
  ──────────────┼──────────────────────────────────────────
    2           │horizontal line drawing. Double outline
                │y=cnt, x=var.
  ──────────────┼──────────────────────────────────────────
    3           │vertical line drawing. Double outline.
                │x=cnt, y=var.

   pos value    │ use and operation*
  ══════════════╪══════════════════════════════════════════
    0           │no replacement is done.
  ──────────────┼──────────────────────────────────────────
    1           │replacement with end direction trace.
                │(used at the beginning of line)
  ──────────────┼──────────────────────────────────────────
    2           │replacement with beginning direction trace.
                │(used at the end of line)
  ──────────────┼──────────────────────────────────────────
    3           │replacement with both directions trace.
                │(used at the middle of line)

    * If character read at position doesn't exist in mkline_mat
    buffer or if it is FFh, not depending of pos value, it is internally
    assumed to be 3.

    The identification and replacement algorithm used by mkline_aux is based
  in finding the character's index on mkline_mat buffer and Boolean ORing it
  with mode and pos arguments.
  Uses functions ~getcrtchar~, ~getcrtcolor~ and ~printc~.

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% Examples:
    ~mkline_aux example 1~        ~mkline_aux example 2~

:mkline_aux example 1
%   mkline_aux example 1
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int c0,c1;
    fillscr ('░',0x19);
    prints ("* * * mkline_aux Example and use of mkline_mat * * *",14,1,0x1e);
    fillbar (mkline_mat[0x18],10,6,25,6,0x1f); //try also with mkline_mat[0x38]
    prints ("pos = ",10,8,0x1f);
    for (c0=0;c0<4;c0++)
     {
       getch ();
       printc (c0+0x30,16,8,0x1e);
       for (c1=0;c1<4;c1++)
        {
          mkline_aux (6,4*c0+c1+10,0,c0,0x1e); //draws the line over frame
                                            //characters.
          mkline_aux (4,4*c0+c1+10,0,c0,0x1e); //draws the upper line.
             //notice that it is the same call, the only difference is y value,
             //drawing the line where there's no frame character.
          //try also with argument mode=2 in calls to mkline_aux
        }
     }
    getch ();
  }

:mkline_aux example 2
%   mkline_aux example 2
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 //This program displays the contents of mkline_mat buffer onscreen and
 //what happens to the copy of mkline_mat on screen (inside the blue boxes)
 //after a call to mkline_aux.
 //Inside the green box is the contents of mkline_mat unchanged

 void main ()
  {
    int c0,c1,c2,c3;
    int a0,a1;
    for (c0=0;c0<4;c0++)
     {
       fillscr ('░',0x19);
       prints("* * * mkline_aux example and use of mkline_mat * * *",14,1,0x1e);
       setcrtwin(10,15,19,24);
       molduradw(0x1a);
       printtext((char *)mkline_mat,0,0,0x1f);
       prints (" => Contents of mkline_mat, unchanged.",26,20,0x1e);
       moldurad(39,16,47,18,0x1e);
       printsf (40,17,0x1f," pos=%d ",c0);
       for (c1=0;c1<4;c1++)
        {
          printsf (6+c1*20,3,0x1f,"mode = %d",c1);
          setcrtwin (5+c1*20,4,14+c1*20,13);
          molduradw(0x1b);
          printtext((char *)mkline_mat,0,0,0x1f);
          for (c2=0;c2<8;c2++)
             for (c3=0;c3<8;c3++)
              {
                if (!(c1%2))
                   mkline_aux(c2+5,c3+c1*20+6,c1,c0,0x1e);
                 else
                   mkline_aux(c2+c1*20+6,c3+5,c1,c0,0x1e);
              }
        }
       getch ();
    }
  }


:mkline
% ▄▄▄▄▄▄▄▄
% ▌mkline▐                             <~CRT.H~>
% ▀▀▀▀▀▀▀▀
    Draws a menu frame line, performing automatic character replacement
  when it founds a menu frame character on its path.

% Declaration:
    void  mkline (int cnt, int bgn, int end, int color, unsigned int mode);

  Purpose:

    This function has been developed to make easy the programmer's work in
  drawing menu lines inside a box. For example, imagine that you have a menu
  box like the one draw below:

    ╔═══════╗
    ║       ║
    ║       ║
 A->║       ║<-B
    ║       ║
    ║       ║
    ╚═══════╝

    If you desired to divide it in two parts by drawing a line from A to
   B, you would have print a string from A to B with character '─'. The
   frame would appear in the best like this:

    ╔═══════╗
    ║       ║
    ║       ║
 A->║───────║<-B
    ║       ║
    ║       ║
    ╚═══════╝

    Note that the corners A and B aren't OK. The best would be the following:

    ╔═══════╗
    ║       ║
    ║       ║
 A->╟───────╢<-B
    ║       ║
    ║       ║
    ╚═══════╝

     One solution would be to print the characters ('╟' and '╢') at positions
  A and B, but that is too hard, because you need to know the ASCII codes of
  these characters, make one call to ~prints~ and two calls to ~printc~. With
  mkline, all you have to do is to supply it with the coordinates of A and
  one coordinate of B (only one is needed, because the other is supplied by A),
  the outline and the orientation of the line to be draw. Which becomes easier
  if you use ~linha...~ macros defined in CRT.H

% Remarks:
    The replacement is done from A thru B.

    Arguments:
    Arg.  │ What it is? What it does?
  ════════╪═══════════════════════════════════════════════════════════════════
   cnt    │ is the common coordinate of A and B
   bgn    │ is the other A coordinate
   end    │ is the other B coordinate
   mode   │ defines the orientation and outline of the line to be draw.
    If (cnt==column) bgn,end==row. If (cnt==row) bgn,end==column.

   mode value   │ use and operation.
  ══════════════╪══════════════════════════════════════════
    0           │horizontal line drawing. Single outline
                │y=cnt, x=var.
  ──────────────┼──────────────────────────────────────────
    1           │vertical line drawing. Single outline
                │x=cnt, y=var.
  ──────────────┼──────────────────────────────────────────
    2           │horizontal line drawing. Double outline
                │y=cnt, x=var.
  ──────────────┼──────────────────────────────────────────
    3           │vertical line drawing. Double outline.
                │x=cnt, y=var.


  mkline uses function ~mkline_aux~ as replacement algorithm.

% Return Value:
    None

% Portability:
    See ~Appendix A~.

% See Also:
    ~crtframe~    ~mkline_aux~    ~mkline_mat~

% Examples:
    ~Example 2~

%   crtwin example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    fillscr ('░',0x19);
    printsj ("* * * Simple examples of mkline function * * *",1,0x1e);
    printsj ("- - - Hit any key to continue - - -",24,0x9e);

  //The example above (the one you had to imagine):
    moldurad (20,6,30,10,0x1f);
    getch ();
    mkline (8,20,30,0x1e,0);
    getch ();

  //another example
    moldura (50,6,60,10,0x1f);
    getch ();
    mkline (55,6,10,0x1e,3);
    getch ();
  }

:crtwindow
% ▄▄▄▄▄▄▄▄▄▄▄▄
% ▌crtwindow ▐                         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    Draws a text box with border and title.

% Declaration:
    void crtwindow    (struct ~crtwin_inp~ p0);

% Remarks:
    p0 is the input struct filled with input arguments for crtwindow.
    If p0.title==NULL it doesn't print any title nor lefts any space for the
  title.
    The box coordinates are given by ~crtwin_dta~ global variable.
    Before calling crtwindow crtwin_dta values must be set to values inside
  the screen, otherwise the box will not appear completely.
    crtwindow doesn't truncate the title to fit in the box upper border. So
  if the title is very big or the box is narrow, the title will exceed the
  box width.

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% See Also:
    ~crtframe~    ~mkline~     ~setcrtwin~

% Examples:
    ~Example 3~

%   crtwindow example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    struct crtwin_inp licos;
    licos.title="CRTWINDOW EXAMPLE"; //title
    licos.tcolor=0x1b; //title color
    licos.fchr='▒'; //fill character
    licos.fcolor=0x2a; //fill color
    licos.bcolor=0x1f; //border color
    licos.btype=1; //border type, same of crtframe

    fillscr ('░',0x19);
    setcrtwin (10,5,30,15); //the coordinates for crtwindow
    crtwindow (licos);

    licos.title=NULL;
    licos.fcolor=0x19;
    licos.bcolor=0x1e;
    setcrtwin (52,5,68,14);
    crtwindow (licos);
    getch ();
  }

:savevideo:restorevideo:savevideowin:restorevideowin:savevideow:restorevideow:savevideo...:restorevideo...
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌savevideo,     restorevideo,    ▐   <~CRT.H~>
% ▌savevideowin,  restorevideowin, ▐
% ▌savevideow and restorevideow    ▐
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
   ■ savevideo saves the contents of screen into a far buffer.
   ■ restorevideo restores the contents of screen previously saved into a far
     buffer.
   ■ savevideowin saves the contents of a text window into a far buffer.
   ■ restorevideowin restores the contents of a text window previously saved
     into a far buffer.
   ■ savevideow is similar to savevideowin, but the window coordinates are
     given by ~crtwin_dta~.
   ■ restorevideow is similar to savevideowin, but the window coordinates are
     given by crtwin_dta.


% Declaration:
   ■ char far *savevideo       (char far *s);
   ■ char far *restorevideo    (char far *s);
   ■ char far *savevideowin    (char far *s, int xi, int yi, int xf, int yf);
   ■ char far *restorevideowin (char far *s, int xi, int yi, int xf, int yf);
   ■ char far *savevideow      (char far *s);
   ■ char far *restorevideow   (char far *s);


% Remarks:
    If ~vmode_x~ and ~vmode_y~ corresponds to the actual number of rows and
  columns in current text mode, savevideo and restorevideo use the hole screen.
    savevideowin and restorevideowin use only a rectangle (text window)
  which upper left corner is (xi,yi), and lower right corner is (xf,yf).
    (xi,yi) and (xf,yf) doesn't need to be inside the range given by vmode_x
  and vmode_y for these functions work. For example:
    savevideowin(buffer,-2,-2,100,60);
  is a valid call.
    savevideow/restorevideow calls savevideowin/restorevideowin with:
       xi=crtwin_dta.left;     yi=crtwin_dta.top;
       xf=crtwin_dta.right;    yf=crtwin_dta.bottom;

    In savevideo, the buffer size must be at least 2*(vmode_x * vmode_y) to
  avoid possible data loss, which normally causes unpredictable and
  likely disastrous results, and can lead to serious problems.
    In savevideowin, the buffer size must be at least 2*(yf-yi+1)(xf-xi+1), by
  the same reason as above. (even when xi, xf ,yi ,yf are out of range given
  by vmode_x and vmode_y)
    If you save many screens or windows in the same buffer, remember that
  the buffer size must be at least the sum of required size for each screen or
  window. The formulas above determines the required size for each screen or
  window data storage.
    savevideo and restorevideo use only the memory area that goes from
  ~video_addr~ thru video_addr + 2*vmode_x*vmode_y - 1 (when ~crt_direct~==0),
  and/or the window (0,0) thru (vmode_x-1,vmode_y-1) (always).

    When is defined ~CRT_FULL~ before including CRT.H these functions are
  replaced by macros that have equivalent functionality, but use ~savecrt...~
  and ~restorecrt...~ functions.
   (for further information see these macros or CRT.H file)

% Return Value:
    All these functions return a pointer that points to buffer's next free
  position, that is, the position where the next screen or window can be saved
  or retrieved.

% Portability:
    See ~Appendix A~.

% Hardware Compatibility:
    Depends on ~printc~, ~getcrtchar~ and ~getcrtcolor~ compatibility.

% See Also:
    ~CRT_FULL~ #defines     ~savecrt...~     ~restorecrt...~
    ~crtwin_dta~            ~gettext~        ~puttext~

% Examples:
    ~savevideo example~                ~restorevideo example~
    ~savevideowin example~             ~restorevideowin example~
    ~savevideow example~               ~restorevideow example~

:savevideo example:restorevideo example
%   savevideo and restorevideo example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    char buffer[4096]; //buffer>=4000= 2*(25 * 80) Be sure that vmode_x<=80
                       //and vmode_y<=25
    fillscr ('░',0x19);
    prints ("* * * SAVEVIDEO AND RESTOREVIDEO EXAMPLE * * *",17,1,0x1e);
    prints ("- - - Hit any key to continue - - -",23,24,0x9e);
    getch ();
    savevideo (buffer); //saves in buffer "buffer" the screen contents
    fillscr (' ',7); //clears the screen
    prints ("- - - Hit any key to see previous screen - - -",16,24,7);
    getch ();
    restorevideo (buffer); //restore the screen contents saved in "buffer"
    getch ();
  }

:savevideowin example:restorevideowin example
%   savevideowin and restorevideowin example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    char buffer[420]; // buffer>= 420 = 2*(74-5+1) * (24-22+1)
    fillscr ('░',0x19);
    prints ("* * * SAVEVIDEOWIN AND RESTOREVIDEOWIN EXAMPLE * * *",13,1,0x1e);
    prints ("- - - Hit any key to continue - - -",20,24,0x9e);
    getch ();
    savevideowin (buffer,5,22,74,24); //saves in "buffer" a text window
    fillscr (' ',0x07); //clears the screen
    prints ("- - - Hit any key to see a part of previous screen - - -",11,23,7);
    getch ();
    restorevideowin(buffer,5,11,74,13);//restores saved window at a new position
    getch ();
  }

:savevideow example:restorevideow example
%   savevideow and restorevideow example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    char buffer[462]; // buffer>= 462 = 2*(50-30+1) * (15-5+1)
    fillscr ('░',0x19);
    printsj ("* * * SAVEVIDEOW AND RESTOREVIDEOW EXAMPLE * * *",1,0x1e);
    printsj ("- - - Hit any key to continue - - -",24,0x9e);
    setcrtwin(30,5,50,15);
    molduradw (0x1e);
    fillbarw ('■',0x18);
    printsj("This box is stored",1,0x1f);
    printsj("in a buffer",2,0x1f);
    getch ();
    savevideow (buffer);
       //saves in "buffer" the text window defined by crtwin_dta
    fillscr (' ',0x07); //clears the screen
    prints ("- - - Hit any key to see the text box again - - -",16,23,7);
    getch ();
    restorevideow (buffer);
       //restores saved window at position given by crtwin_dta
    getch ();
  }

:CRT_FULL:SAVECRT·:RESTORECRT·:SAVECRTWIN·:RESTORECRTWIN·
%  CRT_FULL #defines                   <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

  SAVECRT, RESTORECRT, SAVECRTWIN, RESTORECRTWIN, OR CRT_FULL are #defines
  needed to be defined before including CRT.H to include ~savecrt...~ and
  ~restorecrt...~ functions. They have been created to allow optimization
  (about 600 bytes all them together).

  For example:
    savecrt has the same functionality of savevideo, the difference is that
  savecrt has more options than savevideo, being larger. So if the program
  requires only savevideo, it would be a waste of memory and code to use
  savecrt working as savevideo. But if a program requires both savevideo
  and savecrt, it would be a waste to include savevideo, because savecrt can
  do everything as well as savevideo does and there's almost no difference in
  execution time between both functions, so including savevideo code's would
  be useless. It would pay off including both functions only if both appears
  hundreds time in source code, in a way that the extra argument that savecrt
  has would make difference in size.
    So what has been done is a mechanism that allows only one of both
  functions to be used. For example, a program A uses only savevideo (see
  example below), but then the programmer decides to include in this program
  savecrt function (program B).

     Program A:                            Program B:

                                        #define SAVECRT
 #include <CRT.H>                       #include <CRT.H>
 void main ()                           void main ()
  {                                      {
    char s[4000];                          char s1[4000];
    savevideo(s);  //savevideo(s);         char s2[2000];
    .                                      savevideo (s); //savecrt(s,0)
    .                                      savecrt (s2,2);
    .                                      .
    .                                      .
                                           .

    To compile program B, the programmer will be forced to define SAVECRT
  before including CRT.H. By defining SAVECRT, savevideo is replaced by a
  macro with the same name that calls savecrt. So, even if the source code
  appears to use both functions, in fact it uses only savecrt.
    However if the programmer wishes to include both functions in the
  compiled code, he/she has to undefine the macro that replaces savevideo
  before the call to savevideo, as follows:
    #undef savevideo

    The same idea is valid for other functions listed in the table below
  with their respectively macros and equivalent functions:

  ~savevideo~        ~savecrt~        SAVECRT
  ~restorevideo~     ~restorecrt~     RESTORECRT
  ~savevideowin~     ~savecrtwin~     SAVECRTWIN
  ~restorevideowin~  ~restorecrtwin~  RESTORECRTWIN
  ~savevideow~       ~savecrtw~       SAVECRTWIN
  ~restorevideow~    ~restorecrtw~    RESTORECRTWIN


    If you use all these functions, instead of defining these four macros
  in the table above, you may define CRT_FULL. By doing so, CRT.H
  automatically defines these four macros.

 #define CRT_FULL
    is the same as (internally defines)
 #define SAVECRT
 #define RESTORECRT
 #define SAVECRTWIN
 #define RESTORECRTWIN

    For further information see CRT.H file.
    If you think that this macro structure is too complicated, you may remove
  it editing CRT.H file.

:savecrt:restorecrt:savecrtwin:restorecrtwin:savecrtw:restorecrtw:savecrt...:restorecrt...
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌savecrt,      restorecrt,   ▐       <~CRT.H~>
% ▌savecrtwin,   restorecrtwin,▐
% ▌savecrtw  and restorecrtw   ▐
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
  These functions do the following:
   ■ savecrt saves the contents of screen into a far buffer;
   ■ restorecrt restores the contents of screen previously saved into a far
     buffer;
   ■ savecrtwin saves the contents of a text window into a far buffer;
   ■ restorecrtwin restores the contents of a text window previously saved
     into a far buffer;
   ■ savevideow is similar to savevideowin, but the window coordinates are
     given by crtwin_dta.
   ■ restorevideow is similar to savevideowin, but the window coordinates are
     given by crtwin_dta.

  all them with options (mode).

% Declaration:
   ■ char far *savecrt      (char far *s, int mode);
   ■ char far *restorecrt   (char far *s, int mode);
   ■ char far *savecrtwin   (char far *s, int xi, int yi, int xf, int yf,
                             int mode);
   ■ char far *restorecrtwin(char far *s, int xi, int yi, int xf, int yf,
                             int mode);
   ■ char far *savecrtw     (char far *s, int mode);
   ■ char far *restorecrtw  (char far *s, int mode);


% Remarks:
    savecrt, restorecrt, savecrtwin, restorecrtwin, savecrtw and restorecrtw
  are similar to their ~savevideo...~ and ~restorevideo...~ counterparts,
  except that they have one more input parameter, which defines the mode that
  data must be saved or retrieved from buffer, the mode argument.
    (xi,yi) is the upper left corner.
    (xf,yf) is the lower right corner.
    (xi,yi) and (xf,yf) doesn't need to be inside the range given by vmode_x
  and vmode_y for these functions work. For example:
    savecrtwin(buffer,-2,-2,100,60);
  is a valid call.

    savecrtw/restorecrtw calls savecrtwin/restorecrtwin with:
       xi=crtwin_dta.left;     yi=crtwin_dta.top;
       xf=crtwin_dta.right;    yf=crtwin_dta.bottom;

    If mode==0, these functions work exactly as the same as their ...video...
  counterparts, except that they are a bit larger.

    mode values:

  mode│ Function
 ═════╪══════════════════════════════════════════════════════════════════
   0  │ Writes or reads characters and attributes (colors) sequentially
   1  │ Writes or reads attributes and characters sequentially
   2  │ Writes or reads only characters
   3  │ Writes or reads only attributes
   >3 │ Reserved for future versions

    If mode is greater than 3 the call these functions is ignored and
  they return NULL.

    Hint: You can exchange characters by colors on screen using a call to
 savecrt... with mode==0 and restoring the saved screen (or window) at
 the same position with mode==1.

     To use them is needed to define the matching #define or define CRT_FULL
  before including CRT.H (See table below)

  Function      │ Lines before #include <CRT.H> (in source code)
 ═══════════════╪═════════════════════════════════════════════════════════
 savecrt        │#define SAVECRT        or    #define CRT_FULL
 restorecrt     │#define RESTORECRT     or    #define CRT_FULL
 savecrtwin     │#define SAVECRTWIN     or    #define CRT_FULL
 restorecrtwin  │#define RESTORECRTWIN  or    #define CRT_FULL
 savecrtw       │#define SAVECRTWIN     or    #define CRT_FULL
 restorecrtw    │#define RESTORECRTWIN  or    #define CRT_FULL


    For further information, see CRT_FULL #defines.

    The buffer "s" size must be at least: *
  - for mode==0 or mode==1:
       s>=(2 * vmode_x * vmode_y) => for savecrt and restorecrt
       s>=(2 * (xf-xi+1) * (yf-yi+1)  => for savecrtwin and restorecrtwin
  - for mode==2 or mode==3:
       s>=vmode_x * vmode_y => for savecrt and restorecrt
       s>=(xf-xi+1) * (yf-yi+1)  => for savecrtwin and restorecrtwin

   * Even when xi, xf ,yi ,yf are out of range given by vmode_x and vmode_y

    If you save many screens or windows in the same buffer, remember that
  the buffer size must be at least the sum of required size for each screen
  or window. The formulas above determines the required size for each
  screen or window data storage.

% Return Value:
    On success: These functions return a pointer that points to buffer's
  next free position, that is, the position where can be saved or retrieved
  the next screen or window. (see examples)
    On error: these functions return NULL. (only happens if mode is invalid)

% Portability:
    See ~Appendix A~.

% Hardware Compatibility:
    Depends on ~printc~, ~getcrtchar~ and ~getcrtcolor~ compatibility.

% See Also:
    ~CRT_FULL~ #defines     ~savevideo...~   ~restorevideo...~
    ~crtwin_dta~            ~gettext~        ~puttext~

% Examples:
    ~savecrt example~                  ~restorecrt example~
    ~savecrtwin example~               ~restorecrtwin example~
    ~savecrtw example~                 ~restorecrtw example~

:savecrt example:restorecrt example
%   savecrt and restorecrt example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 /* In this example is used a 4000 bytes buffer. The first 2000 bytes are used
 by the first savecrt call to save the characters from screen, returning
 a pointer that points to the rest of the buffer. This pointer is used by a
 second savecrt call to save the attributes from screen in the remaining 2000
 bytes*/

 #define SAVECRT      //or
 #define RESTORECRT   //#define CRT_FULL

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    char savebuf[4000]; //savebuf>=(25 * 80) + (25 * 80)
    char *savebuf2;
    fillscr ('░',0x19);
    prints ("* * * SAVECRT AND RESTORECRT EXAMPLE * * *",18,1,0x1e);
    prints ("- - - Hit any key to continue - - -",22,24,0x9e);
    getch ();
    savebuf2=(char *)savecrt(savebuf,2);//saves first the characters(2000 bytes)
    savecrt(savebuf2,3); //saves the attributes (remaining 2000 bytes)
    fillscr (' ',0x07);
    printsn ("- - - Hit any key to see previous screen - - -",16,23);
    printsn ("- - - first characters, then colors - - -",18,24);
    getch ();
    savebuf2=savebuf;
    savebuf2=(char *)restorecrt (savebuf2,2);
    getch ();
    restorecrt (savebuf2,3);
    getch ();
  }

:savecrtwin example:restorecrtwin example
%   savecrtwin and restorecrtwin example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 /* In this example is used a 272 bytes buffer. The first 136 bytes are used
 by the first savecrtwin call to save the characters from screen, returning
 a pointer that points to the rest of the buffer. This pointer is used by a
 second savecrtwin call to save the attributes from screen in the remaining
 136 bytes*/

 #define SAVECRTWIN      //or
 #define RESTORECRTWIN   //#define CRT_FULL

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    char savebuf[272]; //savebuf>=272=((72-5+1)*(24-23+1)) +((72-5+1)*(24-23+1))
    char *savebuf2;
    fillscr ('░',0x19);
    prints ("* * * SAVECRTWIN AND RESTORECRTWIN EXAMPLE * * *",18,1,0x1e);
    prints ("- - - Hit any key to continue - - -",22,24,0x9e);
    getch ();
    savebuf2=(char *)savecrtwin(savebuf,5,23,72,24,3); //saves first attributes
    savecrtwin(savebuf2,5,23,72,24,2); //then saves characters
    fillscr (' ',0x07);
    printsj("- - - Hit any key to see a part of previous screen - - -",23,0x07);
    printsj ("- - - first attributes (colors), then characters - - -",24,0x07);
    getch ();
    savebuf2=savebuf;
    savebuf2=(char *)restorecrtwin(savebuf2,5,20,72,21,3);
    getch ();
    restorecrtwin (savebuf2,5,20,72,21,2);
    getch ();
  }

:savecrtw example:restorecrtw example
%   savecrtw and restorecrtw example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 /* In this example is used a 272 bytes buffer. The first 136 bytes are used
 by the first savecrtw call to save the characters from screen, returning
 a pointer that points to the rest of the buffer. This pointer is used by a
 second savecrtw call to save the attributes from screen in the remaining
 136 bytes*/

 #define SAVECRTWIN      //or
 #define RESTORECRTWIN   //#define CRT_FULL

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    char savebuf[272]; //savebuf>=272=((72-5+1)*(24-23+1)) +((72-5+1)*(24-23+1))
    char *savebuf2;
    fillscr ('░',0x19);
    prints ("* * * SAVECRTW AND RESTORECRTW EXAMPLE * * *",18,1,0x1e);
    prints ("- - - Hit any key to continue - - -",22,24,0x9e);
    getch ();
    setcrtwin (5,23,72,24);
    savebuf2=(char *)savecrtw(savebuf,3); //saves first attributes
    savecrtw(savebuf2,2); //then saves characters
    fillscr (' ',0x07);
    prints ("- - - Hit any key to see a part of previous screen - - -",
      12,23,0x07);
    prints ("- - - first attributes (colors), then characters - - -",
      13,24,0x07);
    getch ();
    setcrtwin (5,20,72,21);
    savebuf2=(char *)restorecrtw(savebuf,3);
    getch ();
    restorecrtw (savebuf2,2);
    getch ();
  }

:setcursorsh:getcursorsh
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setcursorsh and getcursorsh▐        <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ setcursorsh changes cursor shape
    ■ getcursorsh gets cursor shape

% Declaration:
    ■ void setcursorsh (unsigned shape);
    ■ int getcursorsh (void);

% Remarks:

    ■ setcursorsh uses function INT 10h / AH = 01h
    ■ getcursorsh uses function INT 10h / AH = 03h

    shape argument bits.  (source: Ralf's Brown ~Interrupt List~ / some tests)
       15 must be 0.
       14,13 cursor blinking
          (00=normal, 01=invisible, 10=erratic, 11=slow)
          (00=normal, other=invisible on EGA/VGA)
       12-8 topmost scan line containing cursor
       7    When calling setcursorsh this bit should be set in some video
            adapters (or system configuration) for the cursor shape be
            correctly changed (undocumented). I've tested setcursorsh in
            my computer (The video adapter is SVGA and DISPLAY.SYS was
            installed) and it worked fine only when this bit was set.
            Do some tests with this bit set and clear.
       4-0  lowermost scan line containing cursor

    setcursorsh loads _AL with ~vmode_mode~, before calling INT 10, to avoid
  problem with some buggy BIOSes
    Important Notice: It has been reported in INT 10h/AH=01h documentation that
  AMI 386 BIOS and AST Premier 386 BIOS will lock up the system if AL is not
  equal to current video mode. So when calling setcursorsh in systems that
  use these BIOSes, be sure that vmode_mode corresponds to the actual selected
  mode.

  On VGA/SVGA systems:
    In 25 rows text modes, the cursor is draw with 16 horizontal lines. In 43
  or 50 rows text modes, the cursor is draw with 8 horizontal lines.

  On CGA systems the cursor is draw with 8 horizontal lines, in 25 rows
 text modes.

  shape example: shape = 0506h

       line 0// ░░░░░░░░
       line 1// ░░░░░░░░
       line 2// ░░░░░░░░
       line 3// ░░░░░░░░
       line 4// ░░░░░░░░
       line 5// ████████
       line 6// ████████
       line 7// ░░░░░░░░

  IMPORTANT: When calling getcursorsh (INT 10h/AH=03h) many ROM BIOSes
  incorrectly return the cursor default size for a color display (start 06h,
  end 07h) when a monochrome display is attached.

% Return Value:
    ■ setcursorsh returns nothing.
    ■ getcursorsh returns the current cursor shape in video page defined by
      crt_page.

% Portability:
    On DOS window mode (WINDOWS), it has same effect.
    See ~Appendix A~ for further information.

% Hardware Compatibility:
    Probably every PC compatible video adapter.

% Examples:

 #include <CRT.H>
 #include <conio.h>

 void main () //turns cursor invisible for a moment
  {
    int a0;
    a0=getcursorsh (); //a0=old cursor shape
    getch (); //pause
    setcursorsh (0x2000); //turns cursor invisible
    getch ();
    setcursorsh (a0); //restores cursor shape
    getch ();
  }

 #include <CRT.H>
 #include <conio.h>

 void showcursorsh (int y)
 //displays the current cursor shape
 //y == row where message will be displayed
  {
    printsf (20,y,0x1f,"%.4Xh :  █",
    getcursorsh());
    getch ();
  }

 void main ()
  {
    int shape;
    textmode (3);
    fillscr (' ',0x1e);
    printsj ("* * * 25 LINES TEXT MODE * * *",0,0x1e);
    printsj ("- - - Hit any key for the next example - - -",15,0x9e);
    shape=getcursorsh(); //saves initial cursor shape
    printsf (4,12,0x1f,"initial shape = %.4Xh :  █",shape);
    //outputs the initial cursor shape
    gotoxy (28,13);
    getch ();

    prints ("selected",3 ,12,0x1f);
    setcursorsh (0x0203);   showcursorsh (12);
    setcursorsh (0x0f0f);   showcursorsh (12);
    setcursorsh (0x000f);   showcursorsh (12);
    setcursorsh (0x0605);   showcursorsh (12);

    textmode (64);
    videomode (64);
    crtwin_dta.bottom=50;
    fillscr (' ',0x1e);
    printsj ("* * * 50 OR 43 LINES TEXT MODE * * *",0,0x1e);
    printsj ("- - - Hit any key for the next example - - -",30,0x9e);
    prints ("selected shape =",3,22,0x1f);
    gotoxy (28,23);

    setcursorsh (0x0001);   showcursorsh (22);
    setcursorsh (0x0102);   showcursorsh (22);
    setcursorsh (0x0203);   showcursorsh (22);
    setcursorsh (0x0304);   showcursorsh (22);
    setcursorsh (0x0607);   showcursorsh (22);
    setcursorsh (0x080C);   showcursorsh (22);

    barcolor (0,30,79,30,0x11);
    printsj ("- - - HIT ANY KEY TO EXIT - - -",30,0x9c);
    getch ();
    textmode (3); //set default text mode
    setcursorsh (shape);//restores initial cursor shape.
   }

:setpalreg:getpalreg
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setpalreg and getpalreg▐            <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ setpalreg sets a single palette register value, enabling to change usual
       text colors by others.
    ■ getpalreg gets individual palette register value.

% Declaration:
    ■ void setpalreg (int regpal, int val);
    ■ int getpalreg (int regpal);

% Remarks:
    ■ setpalreg uses function INT 10h / AX = 1000h
    ■ getpalreg uses function INT 10h / AX = 1007h

    setpalreg loads the register given by (regpal) with value given by (val).
    For (regpal == 00h through 0Fh) regpal is a palette register and val is a
  DAC register.
    For (regpal == 11h) regpal is overscan color register and val is a DAC
  register.
    For (regpal == 10h,12h,13h,14h) regpal is a specific CRT register and
  val is it's value. You should beware that misprogramming of these register
  may cause undesired results or disastrous results, specially register 10h,
  which you should let BIOS control.
     regpal values greater than 0Fh are undocumented, so not necessarily
  this information above and the table below will be correct for regpal values
  greater or equal to 10h.
    The table below summarizes regpal values and the register accessed

    regpal   Register Accessed

   00-0Fh    palette register
    10h      attribute mode control register (should let BIOS control this)
    11h      overscan color register (see also AX=1001h)
    12h      color plane enable register (bits 3-0 enable corresponding
             text attribute bit)
    13h      horizontal PEL panning register
    14h      color select register

    The DAC register is the register that holds the color that's is being
  used as overscan color and/or by a (or many) palette register.
    In most CRT.H functions and ~CONIO.H~ functions the color/attribute
  is a combination where bits 6-4 selects the palette register for background
  color and bits 3-0 selects the foreground color. Bit 7 is usually text
  blinking enable bit, but it may be reprogrammed to be background color
  bit. (see ~settextblink~ and ~Appendix B~)
    In VGA/SVGA or better adapters, the DAC register for a palette register
  or is selected by the (6 or 4) least significant bits of palette register
  value plus current video DAC color page times the size (in DAC registers)
  of a page. (see also setdacpage).
    In other adapters the DAC register for a palette register is given by
  it's value (not tested).

    The overscan register is not affected by DAC registers paging.

     For further details see the source code and INT 10h / AX=(1000h/1007h) in
  Ralf's Brown ~Interrupt List~.

  Standard values for palette registers:

     regpal* │     Color    │ val**
   ══════════╪══════════════╪═══════
       0     │ BLACK        │  0
       1     │ BLUE         │  1
       2     │ GREEN        │  2
       3     │ CYAN         │  3
       4     │ RED          │  4
       5     │ MAGENTA      │  5
       6     │ BROWN        │ 20
       7     │ LIGHTGRAY    │  7
       8     │ DARKGRAY     │ 56
       9     │ LIGHTBLUE    │ 57
      10     │ LIGHTGREEN   │ 58
      11     │ LIGHTCYAN    │ 59
      12     │ LIGHTRED     │ 60
      13     │ LIGHTMAGENTA │ 61
      14     │ YELLOW       │ 62
      15     │ WHITE        │ 63
   ──────────┼──────────────┼───────
      17***  │ OVERSCAN     │  0

   * palette register number (onscreen text color (see ~Appendix B~))
  ** palette register value (range: 0-63) (same of EGA_COLORS)
 *** overscan register (undocumented) (see ~setbordercolor~)
     The range of overscan register value is 0-255 in VGA+ video adapters.

% Hardware Compatibility:
    ■ setpalreg: PCjr,Tandy,EGA,MCGA,VGA and above
    ■ getpalreg: EGA(with UltraVision v2+), VGA, UltraVision v2+, and above

% Portability:
    Will depend most of INT 10h/AX=1000h (for setpalreg) and INT 10h/AX=1007h
  (for getpalreg) BIOS functions.
    See also ~Appendix A~ for further information.

% See Also:
   Ralf's Brown ~Interrupt List~   ~setbordercolor~    ~getbordercolor~
   ~setdacreg~    ~getdacreg~

% Examples:
    ~Example 5~    ~Example 6~

%   setpalreg and getpalreg example:

    To run this example you will need at least a VGA adapter or an EGA adapter
  with UltraVision v2+.

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int a0,a1;
    fillscr (' ',0x07);
    printsj ("- - - Hit any key to turn black \
 into white and write into black - - -",2,0x8f);
    getch ();

 //Exchanges palette register 0 and 15 values
    a0=getpalreg (0);
    a1=getpalreg (15);
    setpalreg(0,a1);
    setpalreg(15,a0);
    printsj (" - - - Hit any key to unexchange colors - - - ",3,0x83);
    getch ();

 //Restores old palette register 0 and 15 values
    setpalreg(0,a0);
    setpalreg(15,a1);
    printsj (" - - - Hit any key to return - - -",24,0x8e);
    getch ();
  }

:setbordercolor:getbordercolor
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setbordercolor and getbordercolor▐  <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ setbordercolor sets overscan color register value.
    ■ getbordercolor reads overscan color register value.

% Declaration:
    ■ void setbordercolor (int val);
    ■ int  getbordercolor (void);

% Remarks:
    ■ setbordercolor uses function INT 10h / AX = 1001h
    ■ getbordercolor uses function INT 10h / AX = 1008h

    The value returned by getbordercolor or stored in setbordercolor is the
  value of overscan color register. This value is the number of a DAC register.
    The color displayed is given by the DAC register for the overscan color
  register.
    The overscan register is not affected by DAC registers paging.
    BUG: In setbordercolor, the original IBM VGA BIOS incorrectly updates the
  parameter save area and places the border color at offset 11h of the palette
  table rather than offset 10h.

% Hardware Compatibility:
    ■ setbordercolor: PCjr,Tandy,EGA,VGA and above
    ■ getbordercolor: EGA(with UltraVision v2+), VGA, UltraVision v2+, and above

% Portability:
    Will depend most of INT 10h/AX=1001h (for setbordercolor) and
  INT 10h/AX=1007h (for getbordercolor) BIOS functions.
    See also ~Appendix A~ for further information.

% See Also:
    Ralf's Brown ~Interrupt List~   ~setpalreg~   ~getpalreg~
    ~setdacreg~    ~getdacreg~

% Examples:
    ~Example 5~

%   setbordercolor and getbordercolor example:

    To run this example you will need at least a VGA adapter or an EGA adapter
  with UltraVision v2+.

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int a0;
    fillscr (' ',0x07);
    printsj ("- - - Hit any key to change the overscan color - - -",1,0x8f);
    getch ();

  //changes the overscan color
    a0=getbordercolor(); //saves the border color in a0
    setbordercolor(55); //bordercolor will become light yellow

    printsj ("- - - Hit any key to restore the overscan color - - -",2,0x8f);
    getch ();

  //restores the overscan color
    setbordercolor(a0);

    printsj ("- - - Hit any key to continue - - -",3,0x8f);
    getch ();
  }

:setdacreg:getdacreg
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setdacreg and getdacreg▐            <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ setdacreg sets the color of a video DAC register.
    ■ getdacreg reads the color from a video DAC register.

% Declaration:
    ■ void setdacreg (int dacreg, char red, char green, char blue);
    ■ void getdacreg (int dacreg, char *red, char *green, char *blue);

% Remarks:
    dacreg is the DAC register (0-255) and red, green, blue are the red, green
  and blue values to be loaded or read from the DAC register. The range of
  red/green/blue (rgb) values is 0(darkest) to 63(lightest), allowing 256k
  different colors.
    dacreg range is 0 to 255.

    ■ setdacreg uses INT 10h/AX=1010h
    ■ getdacreg uses INT 10h/AX=1015h

% Hardware Compatibility:
    ■ setdacreg: MCGA, VGA or above
    ■ getdacreg: MCGA, VGA or above

% Portability:
    Will depend most of INT 10h
  See also ~Appendix A~ for further information.

% See Also:
    Ralf's Brown ~Interrupt List~          ~setpalreg~    ~getpalreg~
    ~setbordercolor~     ~getbordercolor~    ~setdacpage~   ~setdacpgmode~
    ~getdacpgstate~

% Examples:
    ~Example 6~

%   setdacreg and getdacreg example:

    To run this example you will need at least a VGA or MCGA adapter. Works
  fine in a SVGA or better adapter.

 #include <CRT.H>
 #include <conio.h>

 // This program replaces the black color temporarily by another, by
 // replacing the DAC register 0 value and restoring it's old value after.
 // The DAC register 0 usually is selected by palette register 0(black)

 void main ()
  {
    char red,green,blue;

    fillscr ('.',0x07);
    prints ("Hit any key to change  the black color",5,1,0x0f);
    getch ();

    getdacreg (0,&red,&green,&blue); //saves old values in red,green,blue
    setdacreg (0,12,0,24); //changes the black color (DAC register 0)
    prints ("restore",20,1,0x0f);
    getch ();

    setdacreg (0,red,green,blue); //restores the color
    prints ("return.................",20,1,0x0f);
    getch ();
  }

:pgmode:DACPAGE_64:DACPAGE_16
%   setdacpgmode pgmode argument
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

  The values for pgmode are:

     value  │ Symbolic Constants │ number of pages (n) │ size of each page*
    ════════╪════════════════════╪═════════════════════╪═══════════════════
       0    │ DACPAGE_64         │          4          │       64
       1    │ DACPAGE_16         │         16          │       16

    * Number of DAC registers per page.

% See Also:
    ~setdacpgmode~

:setdacpage:setdacpgmode:getdacpgstate
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setdacpage, setdacpgmode▐           <~CRT.H~>
% ▌ and getdacpgstate      ▐
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ setdacpage selects video DAC color page
    ■ setdacpgmode selects video DAC paging mode
    ■ getdacpgstate gets current video DAC page and paging mode.

% Declaration:
    ■ void setdacpage(int page);
    ■ void setdacpgmode (int pgmode);
    ■ int  getdacpgstate (void);

% Remarks:
    In VGA/SVGA and better adapters the 256 DAC register are grouped in (n)
  pages, each with (x) DAC register. (n) may be 4 or 16. If n==4,x=64 (default).
  If n==16, x=16.
    In these adapters, the DAC register for a palette/overscan register
  is selected by the (6 or 4) least significant bits of it's value plus
  current video DAC color page times the size (in DAC registers) of a page.
    setdacpage set's the current video DAC color page ((0-3) if each page
  has 64 DAC regs, or (0-15) if each page has 16 DAC regs.
    sedacpgmode set's the number of pages and the number of DAC registers
  per page, according to ~pgmode~ value.

    getdacpgstate returns the current video DAC page and paging mode in a word.
  In this word bits (15-8) gives the current page and bits (7-0) returns
  current paging mode. The values for paging mode are the same of pgmode
  (see table above)
  Summarizing: getdacpgstate()/256 returns the current DAC page number.
               getdacpgstate()%256 returns current paging mode.

% Hardware Compatibility:
    All functions: VGA/SVGA and better

% Portability:
    Will depend most of INT 10h
  See also ~Appendix A~ for further information.

% See Also:
   Ralf's Brown ~Interrupt List~             ~setpalreg~   ~getpalreg~
   ~setbordercolor~     ~getbordercolor~       ~setdacreg~   ~getdacreg~

% Examples:
    ~Example 6~

%   setdacpage,setdacpgmode and getdacpgstate example:

 #include <CRT.H>
 #include <conio.h>

 //   dispmsg displays the value returned by getdacpgstate, current video DAC
 //color page and video DAC paging mode
 void dispmsg (void)
  {
    unsigned int a0=getdacpgstate
     ();
    printsjf (1,0x0f,"getdacpgstate returned %.4Xh.  Video DAC color-page \
 = %.2Xh.  Paging mode = %.2Xh.",a0,a0/0x100,a0%0x100);
    getch ();
  }

 void main ()
  {
    fillscr (' ',7); //clears the screen
    dispmsg ();
    setdacpgmode (DACPAGE_16); //sets video DAC paging mode to 1
    dispmsg ();
    setdacpage (1); //selects video DAC page 1
    dispmsg ();
    setdacpage (3);
    dispmsg ();
    setdacpgmode (DACPAGE_64); //sets video DAC paging mode to 0 (VIDEO default)
    setdacpage (0); //selects video DAC page 0 (VIDEO default)
    dispmsg ();
  }

:setchrboxwidth
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setchrboxwidth▐                     <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    Changes the character box width in VGA or better monitors.

% Declaration:
    void setchrboxwidth (int cmd);

% Remarks:
    if cmd == 0, boxwidth set's the character box width to be 9.
    if cmd == 1, boxwidth set's the character box width to be 8.
    if cmd == 2, boxwidth set's the character box width to be 8
  if it was 9 and vice versa.
    boxwidth works only in modes (0,1,2,3 and 7 (including extensions
  of these modes with more lines)).

    The video adapter base address is given by ~crt_EVGA_addr~. It's default
  value is 3C0h. If you are using a alternate VGA adapter, change this value
  to 2C0h (alternate EGA/VGA)

    Use this function with care, I can't guarantee that it will work fine in
  your system.

% Return Value:
    None.

% Hardware Compatibility:
    VGA, SVGA or better.

% Portability:
    See ~Appendix A~.

% See Also:
    Ralf's Brown ~Interrupt List~    PC Ports 03C4h,03C5h,03CCh,03C2h

% Example:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    fillscr ('░',0x19);
    setchrboxwidth (0);
    getch ();
    setchrboxwidth (1);
    getch ();
    setchrboxwidth (2);
    getch ();
    setchrboxwidth (2);
    getch ();
    setchrboxwidth (0);
    getch ();
  }

:settextblink
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌settextblink▐                       <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    Toggles color/attribute intensity/blinking bit.

% Declaration:
    void settextblink (int cmd);

% Remarks:
    if cmd==0 instructs video adapter to use color bit 7 as background
  intensity bit
    if cmd==1 instructs video adapter to use color bit 7 as text blink
  enable bit (default)
    if cmd>1 or cmd<0 the call to textblink is ignored.

    To get the state of color bit 7, bit 5 of 0040h:0065h indicates the state.

    textblink uses INT 10h / AX=1003h

% Return Value:
    None.

% Hardware Compatibility:
    Jr, PS, TANDY 1000, EGA, VGA or better.

% Portability:
    See ~Appendix A~.

% See Also:
    ~Appendix B~

% Examples:

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    //message
    fillscr (' ',0x07);
    printsj ("Hit any key to toggle color bit 7 between blink/intensity bit",
       1,0x8F);
    getch ();

    settextblink (0); //define color bit 7 as background intensity bit
    printsj ("Hit any key to return to normal",2,0x8e);
    getch ();

    settextblink (1); //define color bit 7 as blink enable bit (default)
    printsj ("Hit any key to return",3,0x0f);
    getch ();
  }

%   Another example:

 #include <CRT.H>
 #include <conio.h>

 void dispmsg ()
    //displays the value stored at 0040:0065h and bit 5 of this value
  {
    int a0;
    a0=*(char far*)0x00400065L;
    printsf (10,10,0x07,"Contents of memory position 0040:0065h = %.2Xh. \
 (bit 5) = %d", a0,(a0&0x20)/0x20);
    getch ();
  }

 void main ()
  {
    //message
    fillscr (' ',0x07);
    printsj ("Hit any key to toggle color bit 7 between blink/intensity bit",
       1,0x8F);
    dispmsg(); //displays the value stored at 0040:0065h
               //and bit 5 of this value

    settextblink (0); //define color bit 7 as background intensity bit
    printsj ("Hit any key to return to normal",2,0x8e);
    dispmsg();

    settextblink (1); //define color bit 7 as blink enable bit (default)
    printsj ("Hit any key to return",3,0x0f);
    dispmsg();
  }

:changechar_func:CHANGCHR_NORM:CHANGCHR_RECALC
%   changechar_func                    <CRT.H>
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

    changechar_func defines the INT 10h function that is going to be used by
  ~changechar~, the valid values are:

    Symbolic Constant│ Value │ changechar operation
    ═════════════════╪═══════╪══════════════════════════════
     CHANGCHR_NORM   │ 1100h │ only replaces text mode font. (default)
                     │       │
     CHANGCHR_RECALC │ 1110h │ replaces text mode font, recalculating character
                               box height, number of display rows and CRT
                               buffer length. CRTC registers are reprogrammed.
                               (page 0 must be active)
                               (meant to be called immediately after a mode set)

:changechar_height:changechar_blk
%   changechar_height and changechar_blk       <CRT.H>
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

    These global variables are used by ~changechar~ and ~changecharg~

    changechar_height defines the height of characters (in pixels) and the
  size of each character pattern(in bytes) in call to changechar or
  changecharg.

    changechar_blk defines the block to load in map 2. (changechar only)


:changechar:changecharg
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌changechar and changecharg▐         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀
    ■ changechar replaces text mode character patterns with user specified
      patterns
    ■ changecharg replaces graphics mode character patterns with user
      specified patterns

% Declaration:
    ■ void changechar (unsigned char *fmt, int ind, int qt);
    ■ void changecharg (unsigned char *fmt, int rows);

% Remarks:
    (fmt) is the buffer that holds the user specified patterns.
    (ind) is the index of the first character that has it's pattern changed
    (qt) is the count of patterns to store (starting at character (ind))
    (rows) number of rows.
    In text mode, changecharg sets the number of scroll lines to (rows)

    changechar is also affected by changechar_func, changechar_height and
  changechar_blk global variables.

    ~changechar_func~ defines the operation of changechar.
      (you must see ~changechar_func~)

    ~changechar_height~ defines the character height.

    ~changechar_blk~ defines the block to load in map 2.

  Use changechar with changechar_func==CHANGCHR_RECALC if you want to change
  current character height and number of screen rows. When calling changechar
  with changechar_func == CHANGCHR_RECALC, page 0 must be active.

    If changechar_func value is incorrect, the call to changechar is ignored.
  This is to avoid the possibility of calling wrong INT 10 functions.

    changecharg is only affected by changechr_height global variable.

    changechar causes a mode set, completely resetting the video environment,
  but without clearing the video buffer.

    changechar and changecharg are designed to be called immediately after a
  mode set.

   ■changechar uses INT 10h/AX=changechar_func
   ■changecharg uses INT 10h/AX=1121h

% Hardware Compatibility:
    Both functions: PS, EGA, VGA, SVGA or better.

% Portability:
    Will depend most of INT 10h
  See also ~Appendix A~ for further information.

% See Also:
    Ralf's Brown ~Interrupt List~

% Examples:
     ~changechar example~         ~changecharg example~

:changechar example
%   changechar example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    changechar_func=CHANGCHR_NORM; //try also with CHANGCHR_RECALC
    char newpattern[]={
 //this array holds the new character patterns for characters: A B C D E F
  0x00,0x00,0x1C,0x22, 0x42,0x40,0x40,0x40, //Letter A
  0x40,0x62,0x52,0xCD, 0x00,0x00,0x00,0x00, //Letter A
  0x00,0x00,0x38,0x44, 0x42,0x44,0x78,0x44, //Letter B
  0x42,0x42,0x46,0xB9, 0x00,0x00,0x00,0x00, //Letter B
  0x00,0x00,0x0E,0x11, 0x21,0x20,0x20,0x20, //Letter C
  0x20,0x20,0x50,0x8F, 0x00,0x00,0x00,0x00, //Letter C
  0x00,0x00,0x80,0xC4, 0x4A,0x4A,0x4A,0x4A, //Letter D
  0x42,0x42,0x46,0xF9, 0x00,0x00,0x00,0x00, //Letter D
  0x00,0x00,0x3C,0x42, 0x42,0x40,0x30,0x40, //Letter E
  0x40,0x40,0x42,0x3D, 0x00,0x00,0x00,0x00, //Letter E
  0x00,0x00,0x43,0x3F, 0x02,0x02,0x42,0x3F, //Letter F
  0x02,0x02,0x46,0x39, 0x00,0x00,0x00,0x00, //Letter F
    }; //each row is the pattern for a character

    setcrtmode (3);
    fillscr (' ',0x07);
    prints("Hit any key to change the following characters: @ A B C D E F G",
       10,1,0x0f);
    getch ();

    changechar (newpattern, 0x41, 6); //changes the pattern 6 of characters
       //starting at character A (41h)

    getch ();
    setcrtmode (3); //a mode set restores previous character patterns
  }

:changecharg example
%   changechar example
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 #include <CRT.H>
 #include <conio.h>
 #include <stdio.h>

 void main ()
  {
    int k; //user input

    setcrtmode (3);

    fillscr (' ',0x07);
    prints("Hit any key to set the number of scroll lines to 5",10,1,0x0f);
    getch ();

    changecharg (NULL, 5); //changes graphics character to contents of NULL
      //pointer (interrupt vectors). In text mode set the number of scroll
      //lines to 5

   //Writes on screen what user types, until user hits ESC key
    prints ("To exit hit ESC",10,2,0x0f);
    crt_gotoxy (0,3);
    do
     {
       k=getch ();
       if (k==0x0d)
        {
          putchar (k);
          putchar (0x0a);
        }
        else
          putchar(k);
     }
     while (k!=0x1b);

    setcrtmode (3); //a mode set restores default number of scroll lines
  }

:moldura:moldurad
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌moldura and moldurad▐               <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

   ■ moldura is a macro that draws a frame with single outline.
   ■ moldurad is a macro that draws a frame with double outline.

% Declaration:
   ■ void moldura  (xi,yi,xf,yf,color);
   ■ void moldurad (xi,yi,xf,yf,color);

% Remarks:
    Both macros use function ~crtframe~. Their definition are:
       moldura(xi,yi,xf,yf,color)    => crtframe(xi,yi,xf,yf,color,0)
       moldurad(xi,yi,xf,yf,color)   => crtframe(xi,yi,xf,yf,color,1)

    The frame coordinates are given by (xi,yi) and (xf,yf).
    Their name comes from Portuguese language, where "moldura" means frame.
  The letter d in front of moldurad stands for "duplo" (double).

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% See Also:
    ~crtframe~    ~mkline~    ~linha...~    ~molduraw~    ~molduradw~

% Examples:
    ~Example 2~

%  moldura and moldurad example:

 #include <CRT.H>

 void main ()
  {
    moldura (10,5,30,15,0x0a); //draws the first box frame
    moldurad (50,5,70,15,0x0b); //draws the second box frame
  }

:molduraw:molduradw
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌molduraw and molduradw▐             <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

   ■ moldura is a macro that draws a frame with single outline.
   ■ moldurad is a macro that draws a frame with double outline.

% Declaration:
   ■ void molduraw  (color);
   ■ void molduradw (color);

% Remarks:
    Both macros uses function ~crtframew~. Their definition are:
       molduraw(color)    => crtframew(color,0)
       molduradw(color)   => crtframew(color,1)

    The frame coordinates are given by ~crtwin_dta~

% Return Value: none.

% Portability:
    See ~Appendix A~.

% See Also:
    ~crtframew~   ~crtwin_dta~   ~mkline~   ~linha...~   ~moldura~   ~moldurad~

% Example:

 #include <CRT.H>

 void main ()
  {
    setcrtwin (10,5,30,15);
    molduraw (0x0e); //draws the first box frame

    crtwin_dta.left+=40;
    crtwin_dta.right+=40;
    molduradw (0x0f); //draws the second box frame
  }

:linha_hor:linha_ver:linhad_hor:linhad_ver:linha...
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌linha_hor,     linha_ver,▐          <~CRT.H~>
% ▌linhad_hor and linhad_ver▐
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

   ■ linha_hor  draws a horizontal line with single outline.
   ■ linha_ver  draws a vertical line with single outline.
   ■ linhad_hor draws a horizontal line with double outline.
   ■ linhad_ver draws a vertical line with double outline.
  All these macros use automatic frame character replacement algorithm.

% Declaration:

   ■ void linha_hor  (y,xi,xf,color);
   ■ void linha_ver  (x,yi,yf,color);
   ■ void linhad_hor (y,xi,xf,color);
   ■ void linhad_ver (x,yi,yf,color);

% Remarks:
    These macros have been created to make easy ~mkline~ use. They are defined
 as follows:

    linha_hor(y,xi,xf,color)   => mkline(y,xi,xf,color,0)
    linha_ver(y,xi,xf,color)   => mkline(y,xi,xf,color,1)
    linhad_hor(y,xi,xf,color)  => mkline(y,xi,xf,color,2)
    linhad_ver(y,xi,xf,color)  => mkline(y,xi,xf,color,3)

    They are useful to build divisions or lines inside text boxes, text frames
  and anywhere else.
    The name "linha" comes from Portuguese. "Linha" means line
    Further information is available in ~mkline~ and ~mkline_aux~

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% See Also:
    ~moldura~     ~moldurad~     ~molduraw~     ~molduradw~

% Examples:
    ~Example 2~

%  linha_hor, linha_ver, linhad_hor and linhad_ver example:

 #include <CRT.H>

 void main ()
  {
    moldura (10,5,30,15,0x0f); //draws the first box frame
    linha_hor (10,10,30,0x0f); //and create divisions inside
    linha_ver (20,5,15,0x0f); //the box

    moldurad (50,5,70,15,0x0e); //draws the second box frame
    linhad_hor (10,50,70,0x0e); //and create divisions inside
    linhad_ver (60,5,15,0x0e); //the box
  }

  See also example 2 at the end of file.


:janela:janelad
% ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄
% ▌janela and janelad ▐                <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

   ■ janela is a macro that draws a text box with single outline.
   ■ janelad is a macro that draws a text box with double outline.

% Declaration:
   ■ void janela   (struct ~crtwin_inp~ p0);
   ■ void janelad  (struct crtwin_inp p0);

% Remarks:
    Both macros use function ~crtwindow~. Their definition are:
       janela(p0)              =>    p0.type=0;
                                     crtwindow(p0);

       janelad(p0)             =>    p0.type=1;
                                     crtwindow(p0);

    As you can see above these macros changes p0.

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% Example:
    ~Example 3~

:setcrtwin
% ▄▄▄▄▄▄▄▄▄▄▄▄
% ▌setcrtwin ▐                         <~CRT.H~>
% ▀▀▀▀▀▀▀▀▀▀▀▀
    setcrtwindow is a macro defined to make easy the work of assigning values
 for ~crtwin_dta~ global variable.

% Declaration:
   ■ void setcrtwin   (int xi, int yi, int xf, int yf);

% Remarks:
    This macro is the same as the lines below
       crtwin_dta.left=xi;
       crtwin_dta.top=yi;
       crtwin_dta.right=xf;
       crtwin_dta.bottom=yf;

% Return Value:
    None.

% Portability:
    See ~Appendix A~.

% Examples:
    ~Example 3~

:Example 1
%   CRT.H functions Example 1
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄


 #include <CRT.H>
 #include <conio.h>
 #include <stdio.h>

 void main ()
  {
    textmode (3);
    fillscr ('░',0x19);
       //fills the screen with character ░ and color 19h

    prints ("* * * CRT FUNCTIONS EXAMPLE n. 1 * * *",21,0,0x1f);
       //this is a prints example
    getch ();//pauses

    printsn ("TEXT ONLY OUTPUT - PRINTSN",10,2);
    getch ();

    printxy ("PRINTXY EXAMPLE",10,5,2,1,0x20);
    getch ();

    printc ('0',79,0,0x3f);
       //writes 0 at upper right corner with a write color and cyan background
    getch ();

    printcn ('M',79,1); //the same as printc, but with no color. Outputs
       //letter 'M' just below the '0'
    getch ();

    changecolor (79,2,0x1f); //replaces the color at position (79,2) for (1F)h
       //write with a blue background
    getch ();

  //getcrtchar and getcrtcolor example
    printsf(10,10,0x1e,"The character at position (79,0) is '%c' and it's color\
  is (%x)h", getcrtchar (79,0),getcrtcolor (79,0));
    //printsf is a kind o printf that uses prints to output formatted string
    getch ();

    prints ("- - - Hit any key to return - - -",23,24,0x9e);
       //colors greater than 80h are usually blinking in DOS full screen,
       //but aren't in DOS window mode (WINDOWS)

    getch ();
    //the lines below are equivalent to clrscr();
    crt_gotoxy (0,0);
    fillscr (' ',0x07);
  }

:Example 2
%   CRT.H functions Example 2
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄


 #include <CRT.H>
 #include <conio.h>
 //crtframe, mkline, and macros examples.
 //This example contains many sub-examples. Perhaps it is interesting
 //to separate them.

 void main ()
  {
    int i=0,j=0,k=0;

 //crtframe and mkline macros examples

    fillscr ('░',0x19);
    prints ("* * * fillbar, crtframe and mkline example * * *",16,1,0x1e);
    prints ("Using macros moldura... and linha_...",21,2,0x1f);

    moldura (10,5,30,13,0x1f);
    getch ();
    fillbar ('.',11,6,29,12,0x19);
    getch ();
    fillbar ('·',51,6,69,12,0x19);
    getch ();
    moldurad (50,5,70,13,0x1f);
    getch ();

    linha_hor (9,10,30,0x1e);
    getch ();
    linhad_hor (9,50,70,0x1e);
    getch ();
    linha_ver (20,5,13,0x1e);
    getch ();
    linhad_ver (60,5,13,0x1e);
    getch ();
    prints ("- - - Hit any key to continue - - -",22,24,0x9e);
    getch ();

 //crtframe example

    fillscr ('░',0x19);
    prints ("* * * Example of any frames draw by crtframe * * *",15,1,0x1e);
    getch ();

    crtframe (10,5,20,8,0x1f,0);
    prints ("type = 0",11,9,0x1f);
    getch ();

    crtframe (37,5,47,8,0x1f,1);
    prints ("type = 1",38,9,0x1f);
    getch ();

    crtframe (63,5,73,8,0x1f,2);
    prints ("type = 2",64,9,0x1f);
    getch ();

    crtframe (10,15,20,18,0x1f,3);  //default user defined character='█'
    prints ("type = 3",12,19,0x1f);
    getch ();

    crtframe (37,15,47,18,0x1f,'■\1');
      //user defined character is redefined as'■'
    prints ("type = 1FEh",37,19,0x1f);
    getch ();

    crtframe (63,15,73,18,0x1f,3);  //current user defined character='■');
    prints ("type = 3",64,19,0x1f);
    getch ();

 /*
 Remark: Compiler details (Borland's Turbo C++ 3.0)
 'a0' is the same as 0x3061 where 30h and 61 are the ASCII code of '0' and 'a'
 respectively
 'a0' can also be represented by 'a\x30' or 'a\60' or 0x3061 or ...
 '■\1' is the same as 0x01FE
 'a' is the same as 'a\0' = 0x0061. But (for values greater than 7Fh)
 '■' is the same as '■\xff'= 0xfffe that is different from 0x00FE = '■\0'
 */

 //crtframe and mkline example

    #define L0 18     //column initial position
    #define L1 5      //row (line) initial position
    #define L2 8      //each x side size
    #define L3 6      //each y side size
    #define L4 4      //x median
    #define L5 3      //y median
    #define L6 10     //smaller spacing in x
    #define L7 8      //spacing in y
    #define L8 24     //bigger spacing in x
    #define CF 0x1e
    #define CL 0x1f

    fillscr ('░',0x19);
    prints ("* * * FRAME TYPES * * *",28,1,0x1e);
    prints ("Using crtframe and mkline",27,3,0x1b);
    for (i=0;i<2;i++)
       for (j=0;j<2;j++)
          for (k=0;k<2;k++)
           {
             crtframe (L0+L6*k+L8*i,L1+L7*j,L0+L2+L6*k+L8*i,L1+L3+L7*j,CF,i);
             mkline(L1+L5+L7*j,L0+L6*k+L8*i,L0+L2+L6*k+L8*i,CL,2*k);
             mkline(L0+L4+L6*k+L8*i,L1+L7*j,L1+L3+L7*j,CL,2*j+1);
           }
    getch ();
    prints ("- - - Hit any key to return - - -",23,24,0x9f);
    getch();
    crt_gotoxy (0,0); //clears the screen and moves the cursor to upper
    fillscr (' ',0x07); //left corner => these two functions together are
                        //similar to clrscr
  }


:Example 3
%   CRT.H functions Example 3
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄


 #include <CRT.H>
 #include <conio.h>

 //symbolic constants
 #define LEFT_TEXT 0
 #define CENTER_TEXT 1
 #define RIGHT_TEXT 2

 void main ()
  {
    struct crtwin_inp licos;
    textmode(3);
    fillscr ('░',0x19);

 //setcrtwin, janela and janelad examples

 // setcrtwin(-1,-1,80,25); default
    printsj ("* * * MACRO EXAMPLES * * *",0,0x1f);
    licos.title="JANELA EXAMPLE";//if licos.title==NULL doesn't output
                                 //title nor left space for it.
    licos.tcolor=0x1f;
    licos.fchr='░';
    licos.fcolor=0x13;
    licos.bcolor=0x1e;
    setcrtwin(5,5,35,13);
    //licos.btype=0; =>done by janela macro
    janela (licos);
    getch();
    setcrtwin(45,5,75,13);
    licos.title="JANELAD EXAMPLE";
    //licos.btype=1; =>done by janelad macro
    janelad (licos);
    setcrtwin(-1,-1,80,25);
    printsj("- - - Hit any key to continue - - -",24,0x9e);
    getch ();

 //crtwindow and printsj example
    int c0;
    struct crtwin_inp lelecos[4]={
 {"WINDOW 1",0x1f,'░',0x13,0x1e,0},//lelecos[0] declaration
 {"WINDOW 2",0x1f,'░',0x13,0x1e,1},//lelecos[1] declaration
 {"WINDOW 3",0x1f,'░',0x13,0x1e,2},//lelecos[2] declaration
 {"WINDOW 4",0x1f,'.',0x13,0x1e,'■\1'}//lelecos[3] declaration
 //key to each line:
 //{(title),(title color),(chr to fill),(color to fill),(border color),
 //(border type)},
 };
    struct crtwin deflt={-1,-1,80,25};//default values for crtwin_dta
    struct crtwin kiko[4]={{5,3,35,10},{45,3,75,10},{5,13,35,20},{45,13,75,20}};

    fillscr ('░',0x19);
    printsj ("* * * CRTWINDOW EXAMPLE * * *",0,0x1f);
    for (c0=0;c0<4;c0++)
     {
       crtwin_dta=kiko[c0];
       crtwindow(lelecos[c0]);
     }
    crtwin_dta=deflt;//similar to setcrtwin
    printsj("- - - Hit any key to continue - - -",24,0x9e);
    getch();
    setcrtwin(10,0,80,25);
    printsj ("AND PRINTSJ EXAMPLE",0,0x1f);
    for (c0=0;c0<4;c0++)
     {
       crtwin_dta=kiko[c0];
       crtwin_just=0; printsj("LEFT TEXT",0,0x1b);
       crtwin_just=1; printsj("CENTER TEXT",1,0x1f);
       crtwin_just=2; printsj("RIGHT TEXT",2,0x1e);
     }
    crtwin_dta=deflt;
    crtwin_just=CENTER_TEXT;//or 1
    printsj("- - - Hit any key to continue - - -",24,0x9e);
    getch ();
    fillbar ('░',0,0,79,20,0x19);
 //hint call twice crtwindow to draw text box with another title format
    printsj("HINT: call twice crtwindow with different values for p0.btype",
       0,0x1f);
    printsj("to obtain this interesting effect in title",1,0x1f);
    for (c0=0;c0<2;c0++)
     {
       crtwin_dta=kiko[c0];
       crtwindow (lelecos[c0]);
       getch ();
       lelecos[c0].btype=0x00ff;
       crtwindow (lelecos[c0]);
       getch();
     }

 //printtext example
    crtwin_dta.left=24;
    crtwin_dta.top=12;
    crtwin_dta.right=55;
    crtwin_dta.bottom=20;
    licos.title="PRINTTEXT EXAMPLE";
    crtwindow (licos);
    printtext ("Using printtext you can write texts inside a box",3,1,0x1f);
    getch ();

    crtwin_dta=deflt;
    crtwin_just=CENTER_TEXT;//or 1
    printsj("  - - - Hit any key to exit - - -  ",24,0x9e);
    getch ();
  }

:Example 4
%   CRT.H functions Example 4
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

 /* Example of setcrtmode, getcrtmode and setcrtpage */

 #include <CRT.H>
 #include <conio.h>
 #include <dos.h>

 #define PG 3 //page to select
    //0-7 for EGA/VGA   and   0-3 for CGA

 void main ()
  {
    int a0;

    crt_page=10000; //loading crt_page with value that's not actual
    //notice that this page number is impossible

    printsjf (1,0x1f,"vmode_mode=%d vmode_x=%d vmode_y=%d crt_page=%d (not a \
 video page number)",vmode_mode, vmode_x,vmode_y,crt_page);
    getch ();
    a0=getcrtmode();
       //vmode_mode<-current mode   vmode_x<-actual number of columns
       //crt_page<-actual display page a0<-vmode_mode

    printsjf (2,0x1f,"crtmode=%d = vmode_mode=%d vmode_x=%d vmode_y=%d \
 crt_page=%d (current video page)",a0,vmode_mode,vmode_x,vmode_y,crt_page);
    getch ();

    setcrtmode (1); //text mode 1
    a0=getcrtmode();
    printxf (0,1,0x1f,"crtmode=%d = vmode_mode=%d vmode_x=%d \n\tvmode_y=%d \
 crt_page=%d",a0,vmode_mode,vmode_x,vmode_y,crt_page);
    getch ();

    setcrtmode (3); //text mode 3
    setcrtpage (PG); //selects page PG
    printsjf (2,0x1f,"vmode_mode=%d vmode_x=%d vmode_y=%d crt_page=%d \
 video_addr=%Fp",vmode_mode, vmode_x,vmode_y,crt_page,video_addr);
    //notice that each page has a different start address, setcrtpage
    //automatically updates video_addr to page start address.
    getch ();

    setcrtpage(0);
    //selects page 0. video_addr not changed (Reason: no longer used)
  }


:Example 5
%   CRT.H functions Example 5
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

    To run this example you will need at least a VGA adapter or an EGA adapter
  with UltraVision v2+.

 #include <CRT.H>
 #include <conio.h>

 void main ()
  {
    int c0;
    char oldpalette[16]; //used to store original register palette values
    int oldbordercolor; //used to store the original overscan register value

    char newpalette[16]= //new values for the palette
 // {8,25,0,1, 9,41,57,25, 43,11,17,35, 3,27,31,63}; //blue palette
    {63,1,13,2, 23,51,60,62, 16,9,38,26, 21,47,46,31};
    //try also the blue palette.

    int newbordercolor=8; //new value for overscan register

  //Draws the presentation screen and displays some important messages
    fillscr ('░',0x19);
    printsj ("* * * SETPALREG AND GETPALREG EXAMPLE * * *",0,0x1e);
    prints ("The current register values are: ",10,2,0x17);
    fillbar (' ',3,4,32,23,0x17);
    for (c0=0;c0<16;c0++)
     {
       oldpalette[c0]=getpalreg(c0); //saves each palette register in oldpalette

    //displays each palette register number and it's value (DAC register number)
       printsf (5,c0+5,0x1f,"register %2d value= %3d ( )",c0,getpalreg(c0));
       printc ('■',29,c0+5,c0+0x10);
     }
    oldbordercolor=getbordercolor(); //saves overscan register in oldbordercolor
    printsf (4,22,0x1f,"Overscan register value =%3d",oldbordercolor);

  //Message
    prints (" - - - Hit any key to - - - ",40,4,0x9b);
    prints (" - - - change the palette - - -",42,5,0x9b);
    prints (" - - - and overscan color - - -",44,6,0x9b);
    getch ();

  //Changes palette and overscan color
    for (c0=0;c0<16;c0++)
       setpalreg (c0, newpalette[c0]); //replaces the value of each palette
          //register by the value given by newpalette[c0]

    setbordercolor(newbordercolor); //replaces the value of overscan register
       //by newbordercolor. If this doesn't work or locks up your system try
       //using getbordercolor instead.

  //Updates table in the left side
    for (c0=0;c0<16;c0++)
       printsf (24,c0+5,0x1f,"%3d",getpalreg(c0));
    printsf(29,22,0x1f,"%3d",getbordercolor());

  //Message
    prints ("restore the palette - - -",49,5,0x9b);
    getch ();

  //Restores old values of palette and overscan registers
    for (c0=0;c0<16;c0++)
       setpalreg (c0, oldpalette[c0]); //restores the value of each palette
          //register

    setbordercolor (oldbordercolor); //restores the value of overscan register
       //If this doesn't work or locks up your system try using setbordercolor
       //instead.


  //Updates table in the left side
    for (c0=0;c0<16;c0++)
       printsf (24,c0+5,0x1f,"%3d",getpalreg(c0));
    printsf(29,22,0x1f,"%3d",getbordercolor());


  //Message
    fillbar ('░',42,5,74,6,0x19);
    prints (" - - - to exit - - -",42,5,0x9b);
    getch ();
  }

:Example 6
%   CRT.H functions Example 6
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

    To run this example you will need a VGA adapter or better. Works
  fine in a SVGA or better adapter.

 //This program displays the palette register, their values, and allows
 //you to select one palette register, and change it's value. It displays
 //also the DAC register of selected palette register, the current DAC
 //page and paging mode.

 #include <CRT.H>
 #include <conio.h>

 //Displays message about paging mode and current page
 void dacpagemsg ()
  {
    int a0;
    char *n0,*n1;
    a0=getdacpgstate();
    if (a0%256==0) //if paging mode == 0
     {
       n0="4"; n1="64";
     }
     else if (a0%256) //if paging mode == 1
     {
       n0="16"; n1="16";
     }
     else //if paging mode != 0 and 1
     {
       n0="???"; n1="???";
     }
    printsf (40,3,0x0f,"Current page = %d of %s pages.  ",a0/256,n0);
    printsf (40,4,0x0f,"Each page has %s DAC registers",n1);
    printsf (40,5,0x0f,"Current paging mode = %d",a0%256);
  }

 void main ()
  {
    int c0, a0;
    int red,green,blue;
    int palettereg=0, paletteval=0, dacpage=0, dacpgmode=0;
    int k; //input key;
 // char newpalette[]={0,1,2,3, 20,21,22,23, 40,41,42,43, 60,61,62,63};

  //message
    fillscr (' ',0x07);
    printsj ("- - - Please Wait. Writing DAC registers - - -",12,0x8F);

  // changes the color of DAC register from 40h through FFh
    for (c0=64;c0<256;c0++) //changes the color of DAC registers
       setdacreg (c0,((c0/64)*16)%64,((c0/8)*8)%64,(c0*8)%64);

  //message
    fillscr (' ',0x07);
    prints ("Directions: To change palette register type 1.",0,18,0x0b);
    prints ("To change palette register value, type 2 or 3.",10,19,0x0b);
    prints ("To change page, type 4.",10,20,0x0b);
    prints ("To change paging mode, type 5.",10,21,0x0b);
    prints ("To change the DAC register which determines the color of",
       10,22,0x0b);
    prints ("selected palette register type R or G or B.",10,23,0x0b);
    prints ("To finish type ESC",10,24,0x0b);

  //program main loop
    do
     {
       setdacpgmode (dacpgmode); //sets paging mode given by dacpgmode
       setdacpage (dacpage); //sets DAC page
       setpalreg (palettereg, paletteval);
          //changes the value for selected palette register

      //displays the value of each palette register
       for (c0=0;c0<16;c0++)
        {
          printsf (0,c0+2,0x1f,"register %2d value=%3d ( ) ",c0,getpalreg(c0));
          printc ('■',23,c0+2,c0+0x10);
        }

      //Displays message about paging mode and current page
       dacpagemsg ();

      //Displays selected palette register and it's value
       a0=getpalreg(palettereg); //a0 = palette register value
       printsf (40,7,0x0f,"Selected palette register = %2d",palettereg);
       printsf (40,8,0x0f,"Selected palette register value = %3d",a0);

      //Determines the DAC register which gives the color of selected
      //palette register
       if(getdacpgstate()%256==0)
        {
          a0%=64;
          a0+=(getdacpgstate()/256)*64;
        }
        else
        {
          a0%=16;
          a0+=(getdacpgstate()/256)*16;
        }

      //Displays the number of DAC register which determines the color
      //of selected palette register.
       printsf (40,9,0x0f,"Selected palette DAC register = %3d",a0);
       getdacreg(a0,(char *)&red,(char *)&green,(char *)&blue);
       printsf (40,10,0x0f,"DAC register %3d color(rgb) = (%2d,%2d,%2d)",a0,
          red&0x00FF,green&0x00FF,blue&0x00FF);

      //k <= user input
       k=getch ();
       switch (k)
        {
          case '1': //selects another palette register
             palettereg++;
             palettereg%=16;
             paletteval=getpalreg(palettereg);
           break;
          case '3': //changes palette register value
             paletteval+=15;
          case '2': //changes palette register value
             paletteval++;
             paletteval%=256;
           break;
          case '4': //changes video DAC color page
             dacpage++;
             dacpage%=16;
           break;
          case '5': //changes video DAC color paging
             dacpage=0;
             dacpgmode++;
             dacpgmode%=2;
           break;
          case 'R':
          case 'r':
          case 'G':
          case 'g':
          case 'B':
          case 'b':
           //Changes the DAC register which determines the color
                 //of selected palette register.
             if (k=='R')
                red+=8;
             else if (k=='r')
                red++;
             else if (k=='G')
                green+=8;
             else if (k=='g')
                green++;
             else if (k=='B')
                blue+=8;
             else if (k=='b')
                blue++;
             red%=64;
             green%=64;
             blue%=64;
             setdacreg(a0,red,green,blue);
          break;
        }
     }
     while (k!=0x1b); //if user hits ESC, returns

    setcrtmode (3); //set video to mode 3, restoring palette and DAC registers
  }


:Appendix A
%   Appendix A: Portability
%  ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

    These functions have been developed and tested in MS-DOS operating system
 versions 6.22 and 7.0, being executed directly or under WINDOWS (3.11 or 95)
 No compatibility tests with UNIX, ANSI C alone and C++ alone have been done.
 So I can only speculate if these functions will work fine in other compilers
 and other operating systems. I suppose that they may work in UNIX only if the
 hardware and the BIOS are the same of IBM PC machines, perhaps with some
 restrictions, as some functions (for example printx) uses DOS calls. About
 compilers, the user may experience some trouble trying to compile in 32 bit
 mode in newer compilers, in this case you will probably need to change some
 lines of the source code of these functions to solve some portability
 problems.
    At least I know that under Windows some specific hardware functions,
 as changechar or textblink are not effective in a MS-DOS box. However
 they are fully effective if MS-DOS is running in full screen mode.

    If you port these functions to a 32 bit environment, to a 32 bit compiler
 or to DJGPP, let me know.

    If you experience some problems (portability, other) report me to
 [e-mail] or (alternate) [e-mail]
    All these functions have been tested in Borland's Turbo C++ 3.0 (1992) in
 MS-DOS environment. All them have worked fine.

    * * * IMPORTANT: Test these functions thoroughly if you are going * * *
    * * * to use them in other environments than specified.           * * *

   I've tested them a lot and I did them in the best of my ability (in the
 time I had to do them), but I can't guarantee that there's no bug left or
 that they will work in systems that I'm not the owner. I believe they are
 reasonably safe and very hardly would cause problem, but never is too much
 to check for errors and test them.

:Appendix B
%   Appendix B : color Bits
%  ▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀▀

    The color or attribute is given in accordance to bits of (color) argument,
*  which are the same as used by graphics adapters.
    Usually:

  color (DOS or WINDOWS DOS prompt in full screen)  => LRGB IRGB
                                                 background character

  color (WINDOWS DOS prompt in a DOS box)           => IRGB IRGB
                                                 background character

  L = > blinking bit
  I = > intensity (light/normal)
  R = > red
  G = > green
  B = > blue

  bit 7=> in full screen mode or real DOS mode it may be character blinking
  switch (more common) or intensity bit of background color
  (see ~settextblink~).
  In a DOS window box (WINDOWS) it is the intensity bit of background color
  and as I know you can't toggle it between intensity/blink enable bit.

  bit 6=> red bit of background color.
  bit 5=> green bit of background color.
  bit 4=> blue bit of background color

  bit 3=> intensity bit of foreground color (on full screen mode, it may select
  a second DOS font)
  bit 2=> red bit of foreground color.
  bit 1=> green bit of foreground color.
  bit 0=> blue bit of foreground color.

 The bit function is active when it's set (bit==1)
 The characters are draw with foreground color.


 Brief description of color and color indexes:

     index │  index │ index  │
     (dec) │ (hex)  │ IRGB   │ color description
    ═══════╪════════╪════════╪═══════════════════════════
        0  │    0   │ 0000   │black
        1  │    1   │ 0001   │blue
        2  │    2   │ 0010   │green
        3  │    3   │ 0011   │cyan
        4  │    4   │ 0100   │red
        5  │    5   │ 0101   │magenta
        6  │    6   │ 0110   │brown
        7  │    7   │ 0111   │light gray
        8  │    8   │ 1000   │dark gray
        9  │    9   │ 1001   │light blue
       10  │    A   │ 1010   │light green
       11  │    B   │ 1011   │light cyan
       12  │    C   │ 1100   │light red
       13  │    D   │ 1101   │light magenta
       14  │    E   │ 1110   │yellow
       15  │    F   │ 1111   │white

    These colors can be redefined in a EGA or VGA or better monitor using
  ~setpalreg~ or ~setdacreg~(VGA,SVGA or better).

    If you desire you may use combinations of symbolic color constants
 (~CRT_COLORS~) instead of using numbers. For example:
    fillscr ('░',BLUE*BKCOLOR+LIGHTGRAY);
  is the same as:
    fillscr ('░',0x17);

% See Also:
    ~CRT_COLORS~   ~COLORS~   ~textattr~

:Interrupt List
%   Ralf's Brown Interrupt List
%  ▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄▄

    Ralf's Brown Interrupt List is a listing of PC interrupts with over 2Mb of
  text. It's available in the following Web Pages:
    Main site:
      http://www.cs.cmu.edu/afs/cs/user/ralf/pub/WWW/files.html

    Alternate Sites:
      http://www.simtel.net/msdos/info.html
      http://oak.oakland.edu/msdos/info.html => mirror of Simtel Net
      ftp://ftp.cdrom.com/pub/simtelnet/msdos/info/interRRA.ZIP
                                                   interRRB.ZIP
                                                       .
                                                       .
                                                       .
                                                   interRRG.ZIP
        RR is the release number (at the time I wrote this, RR was 60).

    Ralf's Brown E-mail is: [e-mail]

    Perhaps Ralf's Brown Interrupt List is too much detailed, so you may try
  also the Interrupt List that comes with HelpPc (see README.1ST for further
  details)

:··About
%   VIDEO HANDLING FUNCTIONS ver 2.0

 Copyright (C) 1998, 1999 by Márcio A. A. Fialho.
 Email = [e-mail] or [e-mail] (alternate)
 http://pessoal.iconet.com.br/jlfialho
 Freeware / Public Domain.