Cream of the Crop 22/Cream of the Crop 22.iso/disk/cluster2.zip/SOURCE.ZIP/PB3BOXES.BU

Text File | 1996-06-16 | 30KB | 811 lines

'╒═══════════════════════════════════════════════════════════════════════════╕
'│                                                                           │
'│  Text Screen routines for PowerBASIC                                      │
'│  Copyright (c) 1995 by PowerBASIC, Inc.  All Rights Reserved.             │
'│                                                                           │
'│  Note:  These routines are written for maximum speed and will have to be  │
'│         modified to prevent snow on older CGA cards.                      │
'│                                                                           │
'├───────────────────────────────────────────────────────────────────────────┤
'│                                                                           │
'│  LineEdit    -  Edit a line of text; can be longer than the edit window   │
'│  LineInput   -  Get a line of text from the user with a specified limit   │
'│  PgCopy      -  Copy one Text video page to another on a color screen     │
'│  QATTR       -  Change the background attributes of a given location      │
'│  QBOX        -  Display a text box with in a specified color              │
'│  QFILL       -  Fill a specified location with a char and attribute       │
'│  QPRINT      -  Quickly print a string to the screen                      │
'│  QPRINTC     -  Quickly print a centered string to the screen             │
'│  QREST       -  Restore a saved portion of the screen                     │
'│  QSAVE       -  Save a portion of the screen                              │
'│  ScrollDown  -  Scroll a specified portion of the screen down             │
'│  ScrollUp    -  Scroll a specified portion of the screen up               │
'│  SetBlink    -  Change the blink bit status on EGA/VGA text screens       │
'│                                                                           │
'├───────────────────────────────────────────────────────────────────────────┤
'│                                                                           │
'│ 10 June 96 --  Bud Durland                                                │
'│                                                                           │
'│  Modified to store saved screen areas in dynamic strings;  minor bug      │
'│  in QATTR corrected; input routine changed for more control.              │
'│                                                                           │
'│   The original routines in SCRNUNIT were written to save screen           │
'│   areas inINTEGER arrays.  This is OK if you are only doing one box at    │
'│   a time, but is expensive in terms of memory for multiple boxes.         │
'│   Using strings to save screen areas is more economical, since you can    │
'│   create a string array for however many boxes you will be using, and     │
'│   dynamic strings will then only consume enough memory to hold the        │
'│   screen area specified.  An integer array would always have to be        │
'│   dimensioned for the largest possible screen area.                       │
'│                                                                           │
'╘═══════════════════════════════════════════════════════════════════════════╛


$COMPILE UNIT ".\SCRNUNIT.PBU"
$CODE SEG "SCRNLIB"
$CPU      8086      ' Make compatible with XT systems
$LIB      ALL OFF   ' Turn off all PowerBASIC libraries
$ERROR    ALL OFF   ' Turn off all PowerBASIC error checking
$OPTIMIZE SIZE      ' Optimize for smaller code

DEFINT    A-Z       ' Required for all numeric functions, forces PB to not
                    ' include floating point in UNIT (makes it smaller)

DECLARE SUB GetStrLoc()     ' internal string locator in RTL


$INCLUDE ".\PB3BOXES.HDR"      ' includes defs & declares for all modules.


'===========================================================================
' QSAVE - saves specified portion of a text screen in a string
'
' Row   = Starting screen row of area to save
' Col   = Starting screen column of area to save
' Rows  = Number of rows to save (must be 1 or greater)
' Cols  = Number of columns to save (must be 1 or greater)
' Where = string where data is to be saved
'
SUB QSAVE(BYVAL Row  AS INTEGER, BYVAL Col  AS INTEGER, _
          BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER, _
          Where AS STRING) LOCAL PUBLIC

  DIM ScrnSeg AS INTEGER
  DIM WhereMem AS DWORD

  IF (pbvScrnCard AND 1) = 0 THEN
    ScrnSeg = &HB800        ' color monitor
  ELSE
    ScrnSeg = &HB000        ' mono monitor
  END IF

  dLen% = (Rows * Cols) * 2                     ' how much data to store?
  Where = LEFT$(Where + SPACE$(dLen%),dLen%)    ' make string long enough
  WhereMem = STRPTR32(Where)

  ! push DS                 ; save DS for PowerBASIC

  ! les  DI, WhereMem       ; put location of array element in ES:DI
  ! mov  AX, ScrnSeg        ; put screen segment in AX
  ! mov  DS, AX             ; move to DS

  ! mov  AX, Row            ; put row in AX
  ! dec  AX                 ; minus one
  ! mov  CX, 160            ; AX =
  ! mul  CX                 ;   AX * 160
  ! mov  SI, AX             ; put it in SI
  ! mov  AX, Col            ; put column in AX
  ! dec  AX                 ; minus one
  ! shl  AX, 1              ; times 2
  ! add  SI, AX             ; add to SI
  ! mov  DX, Rows           ; put rows in DX
SaveRow:
  ! mov  CX, Cols           ; put number of columns in CX
  ! push SI                 ; save screen offset
  ! rep  movsw              ; copy CX words to array from screen
  ! pop  SI                 ; restore screen offset
  ! add  SI, 160            ; move to next row
  ! dec  DX                 ; one less row to do
  ! jnz  SaveRow            ; if it's zero, we're done

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' QREST - Restores specified portion of a text screen from a string
'
' Row   = Starting screen row of area to restore
' Col   = Starting screen column of area to restore
' Rows  = Number of rows to restore (must be 1 or greater)
' Cols  = Number of columns to restore (must be 1 or greater)
' Where = Starting element of integer array where data is to be restored from
'
SUB QREST(BYVAL Row  AS INTEGER, BYVAL Col  AS INTEGER, _
          BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER, _
          Where AS STRING) LOCAL PUBLIC

  DIM ScrnSeg AS INTEGER
  DIM WhereMem AS DWORD

  IF (pbvScrnCard AND 1) = 0 THEN
    ScrnSeg = &HB800        ' color monitor
  ELSE
    ScrnSeg = &HB000        ' mono monitor
  END IF

  WhereMem = STRPTR32(Where)  ' point to data in string

  ! push DS                 ; save DS for PowerBASIC

  ! lds  SI, WhereMem       ; put location of array in DS:SI
  ! mov  AX, ScrnSeg        ; put screen segment in AX
  ! mov  ES, AX             ; move to ES

  ! mov  AX, Row            ; put row in AX
  ! dec  AX                 ; minus one
  ! mov  CX, 160            ; AX =
  ! mul  CX                 ;   AX * 160
  ! mov  DI, AX             ; put it in DI
  ! mov  AX, Col            ; put column in AX
  ! dec  AX                 ; minus one
  ! shl  AX, 1              ; times 2
  ! add  DI, AX             ; add to DI
  ! mov  DX, Rows           ; put rows in DX
RestoreRow:
  ! mov  CX, Cols           ; put number of columns in CX
  ! push DI                 ; save screen offset
  ! rep  movsw              ; copy CX words to array from screen
  ! pop  DI                 ; restore screen offset
  ! add  DI, 160            ; move to next row
  ! dec  DX                 ; one less row to do
  ! jnz  RestoreRow         ; if it's zero, we're done

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' QBOX - Display a box on the screen
'
' Row  = Starting screen row of box
' Col  = Starting screen column of box
' Rows = Number of rows for the box
' Cols = Number of columns for the box
' Attr = Color attribute of the box
'
SUB QBOX(BYVAL Row  AS INTEGER, BYVAL Col  AS INTEGER, _
         BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER, _
         BYVAL Attr AS INTEGER, BYVAL Bord AS INTEGER) PUBLIC

  DIM ScrnSeg AS INTEGER
  DIM TL.Char AS BYTE
  DIM Vert    AS BYTE
  DIM TR.Char AS BYTE
  DIM Horiz   AS BYTE
  DIM BL.Char AS BYTE
  DIM BR.Char AS BYTE

  IF (pbvScrnCard AND 1) = 0 THEN
    ScrnSeg = &HB800        ' color monitor
  ELSE
    ScrnSeg = &HB000        ' mono monitor
  END IF

  Horiz?   = ASC(MID$(BorderText$(Bord),1,1))
  Vert?    = ASC(MID$(BorderText$(Bord),2,1))
  TL.Char? = ASC(MID$(BorderText$(Bord),3,1))
  TR.Char? = ASC(MID$(BorderText$(Bord),4,1))
  BL.Char? = ASC(MID$(BorderText$(Bord),5,1))
  BR.Char? = ASC(MID$(BorderText$(Bord),6,1))

  ! push DS                 ; save DS for PowerBASIC

  ! mov  AX, ScrnSeg        ; put screen segment in AX
  ! mov  ES, AX             ;  and in ES

  ! mov  AX, Row            ; put row in AX
  ! dec  AX                 ; minus one
  ! mov  CX, 160            ; AX =
  ! mul  CX                 ;   AX * 160
  ! mov  DI, AX             ; put it in DI
  ! mov  AX, Col            ; put column in AX
  ! dec  AX                 ; minus one
  ! shl  AX, 1              ; times 2
  ! add  DI, AX             ; add to DI

  ! mov  DX, Rows           ; put rows in DX
  ! dec  DX                 ; minus top row
  ! dec  DX                 ; minus bottom row

  ! mov  CX, Cols           ; put columns in CX
  ! dec  CX                 ; minus left column
  ! dec  CX                 ; minus right column

  ! mov  AH, Attr           ; put attribute in AH

  ! push CX                 ; save CX (columns)
  ! push DI                 ;  and DI (screen location)
  ! mov  AL, TL.Char?       ; put top left char in AL
  ! stosw                   ; write it to the screen
  ! mov  AL, Horiz?         ; put top char in AL
  ! rep  stosw              ; write it to the screen CX times
  ! mov  AL, TR.Char?       ; put top right char in AL
  ! stosw                   ; write it to the screen
  ! pop  DI                 ; restore DI
  ! pop  CX                 ;  and CX
HorizLoop:
  ! add  DI, 160            ; move to next row on the screen
  ! push CX                 ; save CX
  ! push DI                 ;  and DI
  ! mov  AL, Vert?          ; put left char in AL
  ! stosw                   ; write it to the screen
  ! mov  AL, 32             ; put a space in AL
  ! rep  stosw              ; write it to the screen CX times
  ! mov  AL, Vert?          ; put right char in AL
  ! stosw                   ; write it to the screen
  ! pop  DI                 ; restore DI
  ! pop  CX                 ;  and CX
  ! dec  DX                 ; one less row
  ! jnz  HorizLoop          ; loop until DX (rows) = 0

  ! add  DI, 160            ; move to next row on the screen
  ! mov  AL, BL.Char?       ; put bottom left char in AL
  ! stosw                   ; write it to the screen
  ! mov  AL, Horiz?         ; put bottom char in AL
  ! rep  stosw              ; write it to the screen CX times
  ! mov  AL, BR.Char?       ; put bottom right char in AL
  ! stosw                   ; write it to the screen

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' QFILL - fill area of the screen with specified character and attribute
'
' Row   = Starting screen row of area to fill
' Col   = Starting screen column of area to fill
' Rows  = Number of rows to fill (must be 1 or greater)
' Cols  = Number of columns to fill (must be 1 or greater)
' Char  = ASCII character to fill block with
' Attr  = Color attribute to fill block with
'
SUB QFILL(BYVAL Row  AS INTEGER, BYVAL Col  AS INTEGER, _
          BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER, _
          BYVAL Char AS INTEGER, BYVAL Attr AS INTEGER) PUBLIC

  DIM ScrnSeg AS INTEGER

  IF (pbvScrnCard AND 1) = 0 THEN
    ScrnSeg = &HB800        ' color monitor
  ELSE
    ScrnSeg = &HB000        ' mono monitor
  END IF

  ! push DS                 ; save DS for PowerBASIC

  ! mov  AX, ScrnSeg        ; put screen segment in AX
  ! mov  ES, AX             ;  and in ES

  ! mov  AX, Row            ; put row in AX
  ! dec  AX                 ; minus one
  ! mov  CX, 160            ; AX =
  ! mul  CX                 ;   AX * 160
  ! mov  DI, AX             ; put it in DI
  ! mov  AX, Col            ; put column in AX
  ! dec  AX                 ; minus one
  ! shl  AX, 1              ; times 2
  ! add  DI, AX             ; add to DI
  ! mov  DX, Rows           ; put rows in DX

  ! mov  AX, Char           ; put character in AX
  ! mov  AH, Byte Ptr Attr  ; put attribute in AH
  ! mov  CX, Cols           ; put columns in CX
FillRow:
  ! push DI                 ; save DI
  ! push CX                 ; save CX
  ! rep  stosw              ; write CX words
  ! pop  CX                 ; restore CX
  ! pop  DI                 ; restore DI
  ! add  DI, 160            ; move to next row
  ! dec  DX                 ; one less row
  ! jnz  FillRow            ; loop until DX = 0

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' QATTR - fill area of the screen with specified attribute
'
' Row   = Starting screen row of area to fill
' Col   = Starting screen column of area to fill
' Rows  = Number of rows to fill (must be 1 or greater)
' Cols  = Number of columns to fill (must be 1 or greater)
' Attr  = Color attribute to fill block with
'
SUB QATTR(BYVAL Row  AS INTEGER, BYVAL Col  AS INTEGER, _
          BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER, _
          BYVAL Attr AS INTEGER) PUBLIC

  DIM ScrnSeg AS INTEGER

  IF (pbvScrnCard AND 1) = 0 THEN
    ScrnSeg = &HB800        ' color monitor
  ELSE
    ScrnSeg = &HB000        ' mono monitor
  END IF

  ! push DS                 ; save DS for PowerBASIC

  ! mov  AX, ScrnSeg        ; put screen segment in AX
  ! mov  ES, AX             ;  and in ES

  ! mov  AX, Row            ; put row in AX
  ! dec  AX                 ; minus one
  ! mov  CX, 160            ; AX =
  ! mul  CX                 ;   AX * 160
  ! mov  DI, AX             ; put it in DI
  ! mov  AX, Col            ; put column in AX
  ! dec  AX                 ; minus one
  ! shl  AX, 1              ; times 2
  ! add  DI, AX             ; add to DI
  ! mov  DX, Rows           ; put rows in DX

  ! mov  AL, Byte Ptr Attr  ; put attribute in AL
  ! mov  CX, Cols           ; put columns in CX
RecolorRow:
  ! push DI                 ; save DI
  ! push CX                 ; save CX

RecolorCol:
  ! inc  DI                 ; skip character    ' was after stosb -- bug
  ! stosb                   ; write attribute
  ! loop RecolorCol         ; do it CX times

  ! pop  CX                 ; restore CX
  ! pop  DI                 ; restore DI
  ! add  DI, 160            ; move to next row
  ! dec  DX                 ; one less row
  ! jnz  RecolorRow         ; loop until DX = 0

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' QPRINT - print string to specified location on the screen in specified color
'
' Note:  String is passed BYVAL to make it compatible with fixed length
'        and flex strings.  Since this uses the internal assembler, PB will
'        automatically release the temporary string handle left on the stack.
'        If it were an external assembler routine, it would be responsible for
'        releasing the string.
'
' Row   = Screen row to display text
' Col   = Starting column to display text
' Text  = Text string to display on screen
' Attr  = Color attribute to display characters
'
SUB QPRINT(BYVAL Row  AS INTEGER, BYVAL Col AS INTEGER, _
           BYVAL Text AS STRING, BYVAL Attr AS INTEGER) PUBLIC

  DIM ScrnSeg AS INTEGER

  IF (pbvScrnCard AND 1) = 0 THEN
    ScrnSeg = &HB800        ' color monitor
  ELSE
    ScrnSeg = &HB000        ' mono monitor
  END IF

  ! push DS                 ; save DS for PowerBASIC

  ! push Word Ptr Text      ; push string handle on the stack
  ! call GetStrLoc          ; find the string
  ! jcxz QPExit             ; if it's null, exit

  ! mov  DS, DX             ; put segment in DS
  ! mov  SI, AX             ; put offset in SI
  ! push CX                 ; save length

  ! mov  AX, ScrnSeg        ; put screen segment in AX
  ! mov  ES, AX             ; move to ES

  ! mov  AX, Row            ; put row in AX
  ! dec  AX                 ; minus one
  ! mov  CX, 160            ; AX =
  ! mul  CX                 ;   AX * 160
  ! mov  DI, AX             ; put it in DI
  ! mov  AX, Col            ; put column in AX
  ! dec  AX                 ; minus one
  ! shl  AX, 1              ; times 2
  ! add  DI, AX             ; add to DI

  ! pop  CX                 ; restore length of string
  ! mov  AH, Attr           ; put attribute in AH
WriteChar:
  ! lodsb                   ; get char from string
  ! stosw                   ; write char and attribute to screen
  ! loop WriteChar          ; do it all CX times
QPExit:
  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' QPRINTC - Print a string centered between two columns on the specified
'           row.
'
' Row   = Screen row to display text
' ColL  = Starting column to center displayed text
' ColR  = Ending column to center displayed text
' Text$ = Text string to display on screen
' Attr  = Color attribute to display characters
'
SUB QPRINTC(BYVAL Row  AS INTEGER, BYVAL ColL AS INTEGER, _
            BYVAL ColR AS INTEGER, BYVAL Text AS STRING, _
            BYVAL Attr AS INTEGER)

  DIM Temp AS INTEGER

  Temp = (ColL + ((ColR - ColL) \ 2)) - (LEN(Text$) \ 2)

  QPRINT Row, Temp, Text$, Attr

END SUB


'===========================================================================
' SetBlink - Change the status of the blink bit on EGA/VGA color monitors.
'
' Status - A zero indicates a normal blink bit.  A non-zero indicates
'          the blink bit is a high-intensity background.
'
SUB SetBlink(BYVAL Status AS INTEGER)

  IF BIT(pbvScrnCard, 4) THEN       ' only works on EGA/VGA monitors
    Status = (Status <> 0) AND 1    ' convert to 0 or 1
    ! mov AX, &H1003
    ! mov BX, Status
    ! int &H10
  END IF

END SUB


'===========================================================================
' PgCopy - Copy data from one text page to another
'
' SourcePage = Text page to copy from (starts with 0)
' TargetPage = Text page to copy to (starts with 0)
'
SUB PgCopy(BYVAL SourcePage AS INTEGER, BYVAL TargetPage AS INTEGER) PUBLIC

  DIM PageSize AS INTEGER
  DIM ScrnSeg  AS INTEGER

  IF (pbvScrnCard AND 1) = 1 THEN  ' monochrome adaptor only has 1 page
    EXIT SUB
  END IF

  IF (pbvScrnRows = 25) AND (pbvScrnCols = 80) THEN
    PageSize = 4096                    ' 80x25 = 4k page; could be buggy CGA
  ELSEIF (pbvScrnRows = 25) AND (pbvScrnCols = 40) THEN
    PageSize = 2048                    ' 40x25 = 2k page; could be buggy CGA
  ELSE
    ! push DS                          ; save DS for PowerBASIC
    ! xor  AX, AX                      ; clear AX
    ! mov  DS, AX                      ;  and DS
    ! mov  AX, DS:[&H044C]             ; get page size from BIOS
    ! mov  PageSize, AX                ; put it in PageSize
    ! pop  DS                          ; restore DS for PowerBASIC
  END IF

  SourcePage = SourcePage * PageSize   ' calculate offset of source page
  TargetPage = TargetPage * PageSize   ' calculate offset of target page
  ScrnSeg    = &HB800                  ' only color adaptors have multiple pages

  ! push DS                 ; save DS for PowerBASIC

  ! mov  AX, ScrnSeg        ; put screen segment in AX
  ! mov  ES, AX             ; and in ES
  ! mov  DS, AX             ; and in DS

  ! mov  SI, SourcePage     ; put source page offset in SI
  ! mov  DI, TargetPage     ; put target page offset in DI

  ! mov  CX, PageSize       ; put page size in CX
  ! shr  CX, 1              ; divide by two

  ! rep  movsw              ; move data as words (faster than bytes)

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' ScrollUp - Scroll the specified part of the screen up
'
' Row     = Starting row on screen of scroll area
' Col     = Starting column on screen of scroll area
' Rows    = Total rows on screen of scroll area
' Cols    = Total cols on screen of scroll area
' Attr    = Color attribute for new blank lines
' HowMany = How many lines to scroll in specified area
'
SUB ScrollUp(BYVAL Row AS INTEGER, BYVAL Col AS INTEGER, _
             BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER, _
             BYVAL Attr AS INTEGER, BYVAL HowMany AS INTEGER)

  DECR Row                  ' convert Row to 0 base
  DECR Col                  ' convert Col to 0 base
  INCR Rows, Row - 1        ' convert Rows to bottom row coordinate
  INCR Cols, Col - 1        ' convert Cols to right col coordinate

  ! push DS                 ; save DS for PowerBASIC

  ! mov  AH, 6              ; AH = service 6, scroll up
  ! mov  AL, HowMany        ; AL = number of lines to scroll
  ! mov  BH, Byte Ptr Attr  ; BH = color of new text line
  ! mov  BL, DS:pbvScrnAPage ; BL = active display page
  ! mov  CH, Row            ; CH = starting row
  ! mov  CL, Col            ; CL = starting column
  ! mov  DH, Rows           ; DH = ending row
  ! mov  DL, Cols           ; DL = ending column
  ! int  &H10               ; call Video BIOS

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' ScrollDown - Scroll the specified part of the screen down
'
' Row     = Starting row on screen of scroll area
' Col     = Starting column on screen of scroll area
' Rows    = Total rows on screen of scroll area
' Cols    = Total cols on screen of scroll area
' Attr    = Color attribute for new blank lines
' HowMany = How many lines to scroll in specified area
'
SUB ScrollDown(BYVAL Row AS INTEGER, BYVAL Col AS INTEGER, _
               BYVAL Rows AS INTEGER, BYVAL Cols AS INTEGER, _
               BYVAL Attr AS INTEGER, BYVAL HowMany AS INTEGER)

  DECR Row                  ' convert Row to 0 base
  DECR Col                  ' convert Col to 0 base
  INCR Rows, Row - 1        ' convert Rows to bottom row coordinate
  INCR Cols, Col - 1        ' convert Cols to right col coordinate

  ! push DS                 ; save DS for PowerBASIC

  ! mov  AH, 7              ; AH = service 6, scroll down
  ! mov  AL, HowMany        ; AL = number of lines to scroll
  ! mov  BH, Byte Ptr Attr  ; BH = color of new text line
  ! mov  BL, DS:pbvScrnAPage ; BL = active display page
  ! mov  CH, Row            ; CH = starting row
  ! mov  CL, Col            ; CL = starting column
  ! mov  DH, Rows           ; DH = ending row
  ! mov  DL, Cols           ; DL = ending column
  ! int  &H10               ; call Video BIOS

  ! pop  DS                 ; restore DS for PowerBASIC

END SUB


'===========================================================================
' LineEdit - Allow the end user to edit a text line
'
' Row    = Row to display edit field
' Col    = Column to display edit field
' Text$  = Text string to edit
' Attr   = Color attribute to display string
' EdLen  = Length of edit window
' MaxLen = Maximum edit length
''
' Mods for Library routine -- bud
' GoodKeys$  =  Keys that can be accepted for input.  Good if you want
'               numerics only, etc.  Case insensitive.
' TermKeys$  =  What keys will exit this routine;  If this is blank,
'               Enter and Esc are used.
' ExitKey%   =  tells what key exited this routine.  For two-byte exit keys,
'               (pgUp, DownArrow, etc), this is set to 255 + the ASC of the
'               second byte.
'
SUB LineEdit(BYVAL Row AS INTEGER, BYVAL Col AS INTEGER, _
             Text AS STRING, BYVAL Attr AS INTEGER, _
             BYVAL GoodKeys AS STRING, BYVAL TermKeys AS STRING, _
             ExitKey AS INTEGER, BYVAL EdLen AS INTEGER, _
             BYVAL MaxLen AS INTEGER) PUBLIC

  DIM Ins       AS INTEGER
  DIM Cursor    AS INTEGER
  DIM OldCurX   AS INTEGER
  DIM OldCurY   AS INTEGER
  DIM OldCurTop AS INTEGER
  DIM Begin     AS INTEGER
  DIM I         AS STRING
  DIM Temp      AS STRING

  IF EdLen > MaxLen THEN
    MaxLen = EdLen
  END IF

  Ins       = 0
  Cursor    = 1
  Begin     = 1
  OldCurX   = POS
  OldCurY   = CSRLIN
  OldCurTop = pbvCursor1
  Temp$     = Text$ + SPACE$( MaxLen-LEN(Text$) )

  LOCATE Row, Col+Cursor-1, 1

  DO
    QPRINT Row, Col, MID$(Temp$, Begin, EdLen), Attr
    LOCATE Row, Col + Cursor - 1

    DO
      I$ = INKEY$
    LOOP WHILE LEN(I$) = 0

    SELECT CASE I$
      CASE CHR$(27)                      'Esc
        EXIT DO

      CASE CHR$(13)                      'Return
        EXIT DO

      CASE CHR$(0, 82)                   'Insert
        IF Ins = 0 THEN
          Ins = -1
          LOCATE , , 1, pbvCursor1 - 2, pbvCursor2
        ELSE
          Ins = 0
          LOCATE , , 1, pbvCursor1 + 2, pbvCursor2
        END IF

      CASE CHR$(0, 75)                   'Left arrow
        IF (Begin + Cursor - 1) > 1 THEN
          DECR Cursor
          IF Cursor = 0 THEN
            Cursor = 1
            DECR Begin
          END IF
        END IF

      CASE CHR$(0, 77)                   'Right arrow
        IF (Begin + Cursor - 1) <= LEN(Temp$) THEN
          INCR Cursor
          IF Cursor > EdLen THEN
            Cursor = EdLen
            INCR Begin
          END IF
        END IF

      CASE CHR$(8)                       'Backspace
        IF (Begin + Cursor - 1) > LEN(Temp$) THEN
          Temp$ = LEFT$(Temp$, LEN(Temp$) - 1) + " "
          DECR Cursor
        ELSEIF (Begin + Cursor - 1) > 1 THEN
          Temp$ = LEFT$(Temp$, Begin + Cursor - 3) _
                + MID$(Temp$, Begin + Cursor - 1) + " "
          DECR Cursor
        END IF
        IF Cursor = 0 THEN
          Cursor = 1
          DECR Begin
        END IF

      CASE CHR$(0, 79)                   'End
        Cursor = LEN(RTRIM$(Temp$))+1
        IF Cursor > EdLen THEN
          Begin = Cursor - EdLen + 1
          Cursor = EdLen
        END IF

      CASE CHR$(0, 71)                   'Home
        Cursor = 1
        Begin  = 1

      CASE ELSE
        IF INSTR(TermKeys, I$) > 0 THEN             ' a termination key
          EXIT DO
        END IF

        IF (LEN(GoodKeys) > 0) AND (INSTR(GoodKeys,UCASE$(I$)) = 0) THEN
          ITERATE DO                               ' this key not allowed
        END IF

        IF (Begin + Cursor - 1) <= LEN(Temp$) THEN
          IF ASCII(I$) > 31 THEN
            IF Ins = 0 THEN
              MID$(Temp$, Begin + Cursor - 1, 1) = I$
              INCR Cursor
            ELSE
              IF RIGHT$(Temp$, 1) = " " THEN
                Temp$ = LEFT$(Temp$, Begin+Cursor-2) _
                      + I$ _
                      + MID$(Temp$, Begin+Cursor-1, LEN(Temp$)-(Begin+Cursor-1))
                INCR Cursor
              END IF
            END IF
          END IF
          IF Cursor > EdLen THEN
            Cursor = EdLen
            INCR Begin
          END IF
        END IF

    END SELECT

  LOOP

  ExitKey% = ASC(I$)
  IF LEN(I$) = 2 THEN ExitKey% = 255 + ASC(MID$(I$,2))
  LOCATE OldCurY, OldCurX, 0, OldCurTop, pbvCursor2
  Text = RTRIM$(Temp)

END SUB


'===========================================================================
' LineInput - Allow the end user to input a text line with a specified
'             maximum length.  Uses the FLEXCHR$ value to show the maximum
'             field length.
'
' Default$  = Default for input data
' MaxLength = Maximum length of input data
'
SUB LineInput(Default AS STRING, BYVAL MaxLength AS INTEGER) PUBLIC

  DIM Row       AS INTEGER
  DIM Col       AS INTEGER
  DIM CharCount AS INTEGER
  DIM C         AS STRING

  Row       = CSRLIN                'use the current cursor position
  Col       = POS                   '  to mimic LINE INPUT.
  CharCount = LEN(Default$)

  DO
    LOCATE Row, Col, 0
    PRINT STRING$(MaxLength, FLEXCHR$);  ' show the size of the field
    LOCATE Row, Col, 1                   ' be sure to turn the cursor on
    PRINT Default$;
    DO
      C$ = INKEY$
    LOOP UNTIL LEN(C$)
    SELECT CASE C$
      CASE CHR$(8)                  'backspace
        IF CharCount > 0 THEN       'If more than zero characters, delete one
          DECR CharCount
          Default$ = LEFT$( Default$, LEN( Default$ ) - 1 )
          LOCATE Row, Col, 0        'turn the cursor off
          PRINT Default$;FLEXCHR$;  'erase the deleted char from the screen
        END IF
      CASE CHR$(13)                 'Return was pressed so end loop
        EXIT LOOP
      CASE ELSE
        IF (ASCII(C$)>31) AND (LEN(Default$)<MaxLength) THEN
          Default$ = Default$ + C$  'Add the new character to the string
          INCR CharCount
        END IF
    END SELECT
  LOOP

  LOCATE ,,0   'turn off the cursor
  PRINT        'and move to the next line

END SUB