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PCX_LIB.ARJ
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PCX_DISP.C
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1991-04-07
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/*
*************************************************************************
*
* PCX_DISP.C - PCX_LIB Library Image Display Functions
*
* Version: 1.00B
*
* History: 91/02/14 - Created
* 91/04/01 - Release 1.00A
* 91/04/03 - fixed "segread" call.
* 91/04/07 - Release 1.00B
*
* Compiler: Microsoft C V6.0
*
* Author: Ian Ashdown, P.Eng.
* byHeart Software
* 620 Ballantree Road
* West Vancouver, B.C.
* Canada V7S 1W3
* Tel. (604) 922-6148
* Fax. (604) 987-7621
*
* Copyright: Public Domain
*
*************************************************************************
*/
/*
*************************************************************************
*
* PORTABILITY NOTES
*
* 1. While this program is written in ANSI C, it uses a number of
* function calls that are specific to the Microsoft C V6.0 library.
* These are documented as follows for the purposes of porting this
* program to other compilers and/or processors:
*
* _fmemcpy - "memcpy" for small model / far data
* int86 - execute 80x86 interrupt routine
* int86x - execute 80x86 interrupt routine (far
* data)
* _remapallpalette - remap entire video display color palette
* _selectpalette - select CGA color palette
* outpw - output word to 80x86 I/O port
* segread - get current 80x86 segment register
* values
*
* 2. When porting this program to other processors, remember that words
* are stored by 80x86-based machines in the big-endian format. That
* is, the eight least significant bits (lower byte) are stored
* first, followed by the eight most significant bits (upper byte).
* If PCX-format files are transferred to little-endian machines
* (such as those based on 680x0 and Z8000 processors), the order of
* bytes within each word will have to be reversed before they can
* be interpreted. (This applies to the file header only, since the
* encoded image data and optional 256-color palette are stored as
* bytes.)
*
* 3. MS-DOS does not recognize the 720 x 348 graphics mode of the
* Hercules monochrome display adapter. Therefore, the constant
* PCX_HERC should never be passed as a video mode parameter to any
* BIOS service routine.
*
* The Microsoft C compiler includes a "video mode" parameter
* definition (_HERCMONO) that is defined as 0x08. This is a
* reserved MS-DOS video mode that is apparently used internally by
* the ROM BIOS. It can, however, be passed to the Microsoft C
* library function "_setvideomode" to force the Hercules display
* adapter into graphics mode.
*
* Most other MS-DOS C compilers offer similar library functions to
* force the Hercules monochrome display adapter into its 720 x 348
* graphics mode.
*
*************************************************************************
*/
/* INCLUDE FILES */
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <conio.h>
#include <dos.h>
#include <malloc.h>
#include <graph.h>
#include "pcx_int.h"
/* FORWARD REFERENCES */
static BOOL pcx_read_init(PCX_WORKBLK *, int, int);
static BOOL pcx_read_extpal(PCX_WORKBLK *);
static BOOL pcx_read_header(PCX_WORKBLK *);
static BOOL pcx_read_line(PCX_WORKBLK *, unsigned char *, int);
static BOOL pcx_set_palette(PCX_PAL *, int);
static void pcx_cga_palette(PCX_PAL *, int);
static void pcx_put_cga(PCX_WORKBLK *, unsigned char _far *, int);
static void pcx_put_ega(PCX_WORKBLK *, unsigned char _far *, int);
static void pcx_put_herc(PCX_WORKBLK *, unsigned char _far *, int);
static void pcx_put_vga(PCX_WORKBLK *, unsigned char _far *, int);
/* GLOBALS */
/* PUBLIC FUNCTIONS */
/*
*************************************************************************
*
* PCX_READ - Read PCX Image File
*
* Purpose: To read and display a PCX-format image file.
*
* Setup: BOOL pcx_read
* (
* char *fname,
* int vmode,
* int page
* )
*
* Where: fname is a PCX image file name.
* vmode is the MS-DOS video mode. Valid values are:
*
* PCX_HERC - 720 x 348 Hercules monochrome
* 0x04 - 320 x 200 4-color CGA
* 0x05 - 320 x 200 4-color CGA (color burst off)
* 0x06 - 640 x 200 2-color CGA
* 0x0d - 320 x 200 16-color EGA/VGA
* 0x0e - 640 x 200 16-color EGA/VGA
* 0x0f - 640 x 350 2-color EGA/VGA
* 0x10 - 640 x 350 16-color EGA/VGA
* 0x11 - 640 x 480 2-color VGA
* 0x12 - 640 x 480 16-color VGA
* 0x13 - 320 x 200 256-color VGA
*
* page is the video display page number. Valid values are:
*
* Mode PCX_HERC - 0 or 1
* Mode 0x0d - 0 to 7
* Mode 0x0e - 0 to 3
* Mode 0x0f - 0 or 1
* Mode 0x10 - 0 or 1
* All Other - 0
*
* Return: TRUE if successful; otherwise FALSE.
*
* Note: The video display adapter must be in the appropriate mode
* and active page for the image to be displayed.
*
*************************************************************************
*/
BOOL pcx_read
(
char *fname,
int vmode,
int page
)
{
int bpline; /* Number of bytes per scan line */
int line_num; /* Scan line number */
int max_lines; /* Maximum number of scan lines */
unsigned char *linep; /* PCX scan line buffer pointer */
BOOL status = TRUE; /* Return status */
PCX_WORKBLK *wbp; /* PCX image file workblock pointer */
/* Open a PCX image file workblock */
if ((wbp = pcx_open(fname, FALSE)) == (PCX_WORKBLK *) NULL)
return (FALSE);
/* Initialize the workblock for reading */
if (pcx_read_init(wbp, vmode, page) == FALSE)
{
(void) pcx_close(wbp); /* Close the PCX workblock */
return (FALSE);
}
/* Calculate the image height */
max_lines = wbp->header.yul + wbp->header.ylr + 1;
/* Calculate number of bytes per line (for all color planes) */
bpline = wbp->header.bppscan * wbp->header.nplanes;
/* Allocate the PCX scan line buffer */
if ((linep = (unsigned char *) malloc(bpline)) != (unsigned char *)
NULL)
{
/* Set the file pointer to the beginning of the encoded image data */
if (status == TRUE)
if (fseek(wbp->fp, (long) (sizeof(PCX_HDR)), SEEK_SET) != 0)
status = FALSE;
/* Set the video display adapter color palette unless the PCX file */
/* is Version 3.0 (i.e. - PC Paintbrush Version 2.8 w/o palette) */
if (status == TRUE)
if (wbp->header.version != 3)
if (pcx_set_palette(wbp->palettep, vmode) == FALSE)
status = FALSE;
/* Read the image line by line */
if (status == TRUE)
{
for (line_num = 0; line_num < max_lines; line_num++)
{
/* Read the current scan line */
if ((status = pcx_read_line(wbp, linep, bpline)) == FALSE)
{
status = FALSE;
break;
}
/* Display the current scan line */
wbp->pcx_funcp(wbp, (unsigned char _far *) linep, line_num);
}
}
free(linep); /* Free the PCX scan line buffer */
}
else
status = FALSE;
if (pcx_close(wbp) == FALSE) /* Close the PCX workblock */
status = FALSE;
return (status);
}
/* PRIVATE FUNCTIONS */
/*
*************************************************************************
*
* PCX_READ_INIT - Initialize PCX Workblock For Reading
*
* Purpose: To initialize a PCX image file workblock for reading.
*
* Setup: static BOOL pcx_read_init
* (
* PCX_WORKBLK *wbp,
* int vmode,
* int page
* )
*
* Where: wbp is a PCX workblock pointer.
* vmode is the MS-DOS video mode. Valid values are:
*
* PCX_HERC - 720 x 348 Hercules monochrome
* 0x04 - 320 x 200 4-color CGA
* 0x05 - 320 x 200 4-color CGA (color burst off)
* 0x06 - 640 x 200 2-color CGA
* 0x0d - 320 x 200 16-color EGA/VGA
* 0x0e - 640 x 200 16-color EGA/VGA
* 0x0f - 640 x 350 2-color EGA/VGA
* 0x10 - 640 x 350 16-color EGA/VGA
* 0x11 - 640 x 480 2-color VGA
* 0x12 - 640 x 480 16-color VGA
* 0x13 - 320 x 200 256-color VGA
*
* page is the video display page number. Valid values are:
*
* Mode PCX_HERC - 0 or 1
* Mode 0x0d - 0 to 7
* Mode 0x0e - 0 to 3
* Mode 0x0f - 0 or 1
* Mode 0x10 - 0 or 1
* All Other - 0
*
* Return: TRUE if successful; otherwise FALSE.
*
*************************************************************************
*/
static BOOL pcx_read_init
(
PCX_WORKBLK *wbp,
int vmode,
int page
)
{
int width; /* Display width */
int leftover; /* Number of unseen bits */
BOOL status = TRUE; /* Return status */
/* Read the file header */
if ((pcx_read_header(wbp)) == FALSE)
return (FALSE);
/* Initialize the workblock color palette pointer */
wbp->palettep = wbp->header.palette;
wbp->epal_flag = FALSE;
/* Read the extended palette (if any) */
if (vmode == 0x13 && wbp->header.version == 5)
if (pcx_read_extpal(wbp) == FALSE)
return (FALSE);
/* Initialize the display page address offset */
wbp->page_offset = (unsigned long) 0L;
switch (vmode) /* Select PCX line display function */
{
case PCX_HERC: /* 720 x 348 Hercules monochrome */
/* Hercules monochrome display adapter supports 2 pages */
wbp->page_offset = 0x08000000L * (unsigned long) page;
/* Calculate display width in pixels */
width = min((wbp->header.xlr - wbp->header.xul + 1), 720);
/* Calculate number of bytes to display */
wbp->num_bytes = (width + 7) >> 3;
/* Calculate mask for leftover bits */
if ((leftover = width & 7) != 0)
wbp->mask = (0xff << (8 - leftover)) & 0xff;
else
wbp->mask = 0xff;
wbp->pcx_funcp = pcx_put_herc; /* Set the display function ptr */
break;
case 0x04: /* 320 x 200 4-color CGA */
case 0x05: /* 320 x 200 4-color CGA (color burst off) */
/* Calculate display width in pixels */
width = min((wbp->header.xlr - wbp->header.xul + 1), 320);
/* Calculate number of bytes to display */
wbp->num_bytes = (width + 3) >> 2;
/* Calculate mask for leftover bits */
if ((leftover = (width & 3) << 1) != 0)
wbp->mask = (0xff << (8 - leftover)) & 0xff;
else
wbp->mask = 0xff;
wbp->pcx_funcp = pcx_put_cga; /* Set the display function ptr */
break;
case 0x06: /* 640 x 200 2-color CGA */
/* Calculate display width in pixels */
width = min((wbp->header.xlr - wbp->header.xul + 1), 640);
/* Calculate number of bytes to display */
wbp->num_bytes = (width + 7) >> 3;
/* Calculate mask for leftover bits */
if ((leftover = width & 7) != 0)
wbp->mask = (0xff << (8 - leftover)) & 0xff;
else
wbp->mask = 0xff;
wbp->pcx_funcp = pcx_put_cga; /* Set the display function ptr */
break;
case 0x0d: /* 320 x 200 16-color EGA/VGA */
case 0x0e: /* 640 x 200 16-color EGA/VGA */
case 0x0f: /* 640 x 350 2-color EGA/VGA */
case 0x10: /* 640 x 350 16-color EGA/VGA */
case 0x11: /* 640 x 480 2-color VGA */
case 0x12: /* 640 x 480 16-color VGA */
switch (vmode) /* Initialize the display adapter page offset */
{
case 0x0d: /* 320 x 200 16-color EGA/VGA (8 pages maximum) */
wbp->page_offset = 0x02000000L * (unsigned long) page;
break;
case 0x0e: /* 640 x 200 16-color EGA/VGA (4 pages maximum) */
wbp->page_offset = 0x04000000L * (unsigned long) page;
break;
case 0x0f: /* 640 x 350 2-color EGA/VGA (2 pages maximum) */
case 0x10: /* 640 x 350 16-color EGA/VGA (2 pages maximum) */
wbp->page_offset = 0x08000000L * (unsigned long) page;
break;
default: /* All other modes support only one page */
break;
}
/* Calculate display width in pixels */
width = min((wbp->header.xlr - wbp->header.xul + 1), 640);
/* Calculate number of bytes to display */
wbp->num_bytes = (width + 7) >> 3;
/* Calculate mask for leftover bits */
if ((leftover = width & 7) != 0)
wbp->mask = (0xff << (8 - leftover)) & 0xff;
else
wbp->mask = 0xff;
wbp->pcx_funcp = pcx_put_ega; /* Set the display function ptr */
break;
case 0x13: /* 320 x 200 256-color VGA */
/* Calculate number of bytes to display */
wbp->num_bytes = min((wbp->header.xlr - wbp->header.xul + 1), 320);
wbp->mask = 0; /* Dummy parameter */
wbp->pcx_funcp = pcx_put_vga; /* Set the display function ptr */
break;
default: /* Other display adapters not supported */
status = FALSE;
break;
}
return (status);
}
/*
*************************************************************************
*
* PCX_READ_HEADER - Read PCX File Header
*
* Purpose: To read and validate a PCX file header.
*
* Setup: static BOOL pcx_read_header
* (
* PCX_WORKBLK *wbp
* )
*
* Where: wbp is a PCX image file workblock pointer.
*
* Return: TRUE if successful; otherwise FALSE.
*
* Result: The file header is read into the "header" member of the
* PCX workblock.
*
*************************************************************************
*/
static BOOL pcx_read_header
(
PCX_WORKBLK *wbp
)
{
BOOL status = TRUE; /* Status flag */
PCX_HDR *hdrp; /* PCX file header buffer pointer */
hdrp = &(wbp->header); /* Initialize the file header pointer */
/* Read the file header */
if (fseek(wbp->fp, 0L, SEEK_SET) != 0)
status = FALSE;
if (status == TRUE)
if (fread(hdrp, sizeof(PCX_HDR), 1, wbp->fp) != 1)
status = FALSE;
/* Validate the PCX file format */
if (status == TRUE)
if ((hdrp->pcx_id != 0x0a) || (hdrp->encoding != 1))
status = FALSE;
return (status);
}
/*
*************************************************************************
*
* PCX_READ_EXTPAL - Read Extended Palette
*
* Purpose: To read an extended (256-color) palette (if it exists).
*
* Setup: static BOOL pcx_read_extpal
* (
* PCX_WORKBLK *wbp
* )
*
* Where: wbp is a PCX image file workblock pointer.
*
* Return: TRUE if successful; otherwise FALSE.
*
* Note: It is possible for a PCX image file without an appended
* 256-color palette to have the value 0x0c as the 769th byte
* (the location of the extended palette indicator byte) from
* the end of the file (i.e. - in the encoded image data
* section). This function will misinterpret the following
* 768 bytes of encoded image data as an extended palette.
*
* This problem will only occur if an attempt is made to
* display a PCX image using the wrong MS-DOS video mode. It
* can be detected by decoding the image data and using
* "ftell" to note the file position of the end of the
* encoded image data section, then comparing it to the file
* position of the indicator byte. If the supposed indicator
* byte is located within the encoded image data section, the
* indicator byte is invalid and so the file header palette
* should be used instead.
*
*************************************************************************
*/
static BOOL pcx_read_extpal
(
PCX_WORKBLK *wbp
)
{
int indicator; /* PCX extended palette indicator */
/* Position the file pointer to the extended palette indicator byte */
if (fseek(wbp->fp, -769L, SEEK_END) != 0)
return (FALSE);
/* Read the (assumed) extended palette indicator byte */
if ((indicator = getc(wbp->fp)) == EOF)
return (FALSE);
if (indicator == PCX_EPAL_FLAG) /* Check for indicator byte */
{
/* Allocate an extended palette buffer */
if ((wbp->palettep = (PCX_PAL *) calloc(sizeof(PCX_PAL),
PCX_EPAL_SIZE)) == (PCX_PAL *) NULL)
return (FALSE);
/* Read the extended palette */
if (fread(wbp->palettep, sizeof(PCX_PAL), PCX_EPAL_SIZE, wbp->fp) !=
PCX_EPAL_SIZE)
{
free(wbp->palettep); /* Free the extended palette buffer */
return (FALSE);
}
wbp->epal_flag = TRUE; /* Indicate extended palette present */
}
return (TRUE);
}
/*
*************************************************************************
*
* PCX_READ_LINE - Read PCX Line
*
* Purpose: To read an encoded line (all color planes) from a PCX-
* format image file and write the decoded data to a line
* buffer.
*
* Setup: static BOOL pcx_read_line
* (
* PCX_WORKBLK *wbp,
* unsigned char *linep,
* int bpline
* )
*
* Where: wbp is a PCX image file workblock pointer.
* linep is a PCX scan line buffer pointer.
* bpline is the number of bytes per scan line (all color
* planes).
*
* Return: TRUE if successful; otherwise FALSE.
*
*************************************************************************
*/
static BOOL pcx_read_line
(
PCX_WORKBLK *wbp,
unsigned char *linep,
int bpline
)
{
int data; /* Image data byte */
int count; /* Image data byte repeat count */
int offset = 0; /* Scan line buffer offset */
while (offset < bpline) /* Decode current scan line */
{
if ((data = getc(wbp->fp)) == EOF) /* Get next byte */
return (FALSE);
/* If top two bits of byte are set, lower six bits show how */
/* many times to duplicate next byte */
if ((data & PCX_COMP_FLAG) == PCX_COMP_FLAG)
{
count = data & PCX_COMP_MASK; /* Mask off repeat count */
if ((data = getc(wbp->fp)) == EOF) /* Get next byte */
return (FALSE);
memset(linep, data, count); /* Duplicate byte */
linep += count;
offset += count;
}
else
{
*linep++ = (unsigned char) data; /* Copy byte */
offset++;
}
}
return (TRUE);
}
/*
*************************************************************************
*
* PCX_SET_PALETTE - Set Palette
*
* Purpose: To set the display palette according to a PCX file
* palette.
*
* Setup: static BOOL pcx_set_palette
* (
* PCX_PAL *palettep,
* int vmode
* )
*
* Where: palettep is a pointer to a PCX file palette.
* vmode is the MS-DOS video mode. Valid values are:
*
* PCX_HERC - 720 x 348 Hercules monochrome
* 0x04 - 320 x 200 4-color CGA
* 0x05 - 320 x 200 4-color CGA (color burst off)
* 0x06 - 640 x 200 2-color CGA
* 0x0d - 320 x 200 16-color EGA/VGA
* 0x0e - 640 x 200 16-color EGA/VGA
* 0x0f - 640 x 350 2-color EGA/VGA
* 0x10 - 640 x 350 16-color EGA/VGA
* 0x11 - 640 x 480 2-color VGA
* 0x12 - 640 x 480 16-color VGA
* 0x13 - 320 x 200 256-color VGA
*
* Return: TRUE if successful; otherwise FALSE.
*
*************************************************************************
*/
static BOOL pcx_set_palette
(
PCX_PAL *palettep,
int vmode
)
{
int i; /* Scratch counter */
int red_lo; /* Low red intensity */
int red_hi; /* High red intensity */
int green_lo; /* Green low intensity */
int green_hi; /* Green high intensity */
int blue_lo; /* Blue low intensity */
int blue_hi; /* Blue high intensity */
unsigned char *ega_palp; /* EGA 16-color palette buffer pointer */
unsigned long *vga_palp; /* VGA 256-color palette buffer pointer */
BOOL status = TRUE; /* Return status */
union REGS regs; /* 80x86 register values */
struct SREGS sregs; /* 80x86 segment register values */
switch (vmode)
{
case PCX_HERC: /* 720 x 348 Hercules monochrome */
break;
case 0x04: /* 320 x 200 4-color CGA display */
case 0x05: /* 320 x 200 monochrome CGA display (burst off) */
case 0x06: /* 640 x 200 2-color CGA display */
/* Set the CGA color palette */
pcx_cga_palette(palettep, vmode);
break;
case 0x0d: /* 320 x 200 16-color EGA/VGA */
case 0x0e: /* 640 x 200 16-color EGA/VGA */
case 0x0f: /* 640 x 350 2-color EGA/VGA */
case 0x10: /* 640 x 350 16-color EGA/VGA */
case 0x11: /* 640 x 480 2-color VGA */
case 0x12: /* 640 x 480 16-color VGA */
if (pcx_isvga() == TRUE) /* Check for VGA display adapter */
{
/* Allocate a 16-color VGA display adapter palette buffer */
if ((vga_palp = (unsigned long *) calloc(sizeof(unsigned long),
PCX_PAL_SIZE)) == (unsigned long *) NULL)
{
status = FALSE;
break;
}
/* Map PCX hardware palette to 16-color VGA palette (each color */
/* value is a "long" with the form: */
/* */
/* 00000000-00BBBBBB-00GGGGGG-00RRRRRR */
/* */
/* where each color is a 6-bit value. */
for (i = 0; i < PCX_PAL_SIZE; i++)
vga_palp[i] = (long) (palettep[i].red >> 2) |
((long) (palettep[i].green >> 2)) << 8 |
((long) (palettep[i].blue >> 2)) << 16;
(void) _remapallpalette(vga_palp); /* Remap entire palette */
free(vga_palp); /* Free the VGA palette buffer */
}
else /* EGA display adapter */
{
/* Allocate an EGA display adapter palette buffer */
if ((ega_palp = (unsigned char *) calloc(sizeof(unsigned char),
PCX_PAL_SIZE + 1)) == (unsigned char *) NULL)
{
status = FALSE;
break;
}
/* Map PCX hardware palette to 16-color EGA palette (each EGA */
/* color value is an "unsigned char" with the form: */
/* */
/* 0 0 R' G' B' R G B */
/* */
/* where X' is the low-intensity value and X is the high */
/* intensity value for the color X.) */
/* */
/* NOTE: the "_remapallpalette" function could be used to set */
/* the palette for EGA display adapters. However, this */
/* function does not appear to update the palette */
/* register values in the Dynamic Save Area (see the */
/* function header for "pcx_init_palette" in PCX_FILE.C) */
/* for a detailed explanation). */
for (i = 0; i < PCX_PAL_SIZE; i++)
{
/* Extract low and high intensity bits for each color */
red_lo = (palettep[i].red >> 6) & 0x01;
red_hi = (palettep[i].red >> 6) & 0x02;
green_lo = (palettep[i].green >> 6) & 0x01;
green_hi = (palettep[i].green >> 6) & 0x02;
blue_lo = (palettep[i].blue >> 6) & 0x01;
blue_hi = (palettep[i].blue >> 6) & 0x02;
/* Combine color intensity bits for EGA palette value */
ega_palp[i] = (unsigned char) ((red_lo << 5) | (green_lo << 4) |
(blue_lo << 3) | (red_hi << 1) | green_hi | (blue_hi >>
1));
}
/* Set the border (overscan) color to black (BIOS default) */
ega_palp[16] = (unsigned char) 0;
regs.h.ah = 0x10; /* Select "Set All Palette Registers" */
regs.h.al = 0x02;
/* Get the EGA palette registers buffer offset value */
regs.x.dx = (unsigned int) ega_palp;
segread(&sregs); /* Get the current DS segment register value */
sregs.es = sregs.ds;
int86x(0x10, ®s, ®s, &sregs); /* Call BIOS video service */
free(ega_palp); /* Free the EGA palette buffer */
}
break;
case 0x13: /* 320 x 200 256-color VGA display */
/* Allocate a 256-color VGA display adapter palette buffer */
if ((vga_palp = (unsigned long *) calloc(sizeof(unsigned long),
PCX_EPAL_SIZE)) == (unsigned long *) NULL)
{
status = FALSE;
break;
}
/* Map PCX extended palette to 256-color VGA palette */
for (i = 0; i < PCX_EPAL_SIZE; i++)
vga_palp[i] = (long) (palettep[i].red >> 2) |
((long) (palettep[i].green >> 2)) << 8 |
((long) (palettep[i].blue >> 2)) << 16;
(void) _remapallpalette(vga_palp); /* Remap entire palette */
free(vga_palp); /* Free the VGA palette buffer */
break;
default: /* Other modes not supported */
status = FALSE;
break;
}
return (status);
}
/*
*************************************************************************
*
* PCX_CGA_PALETTE - Select CGA Palette
*
* Purpose: To set the Color Graphics Adapter (CGA) display palette
* according to a PCX file palette.
*
* Setup: static void pcx_cga_palette
* (
* PCX_PAL *palettep,
* int vmode
* )
*
* Where: palettep is a pointer to a PCX file palette.
* vmode is the MS-DOS video mode. Valid values are:
*
* 0x04 - 320 x 200 4-color CGA
* 0x05 - 320 x 200 4-color CGA (color burst off)
* 0x06 - 640 x 200 2-color CGA
*
* Note: ZSoft's PC Paintbrush products no longer support the CGA
* color palette. When a CGA color palette is encountered,
* PC Paintbrush maps it to a monochrome (black and white)
* palette.
*
* MS-DOS video mode 0x05 (320 x 200 monochrome CGA display,
* color burst off) will only display a monochrome image on
* a composite video monitor (typically a television set with
* an RF adapter). All other monitors will display a color
* palette in this mode (which is different for CGA and EGA
* or VGA display adapters).
*
* The "background" color is actually the foreground color
* (i.e. - the color of activated pixels) for MS-DOS video
* mode 0x06. The background color is black for CGA display
* adapters.
*
*************************************************************************
*/
static void pcx_cga_palette
(
PCX_PAL *palettep,
int vmode
)
{
short pal_num; /* Palette number */
BOOL sel_flag; /* Palette selector bit flag */
BOOL int_flag; /* Intensity bit flag */
union REGS regs; /* 80x86 register values */
/* Set the background color */
regs.h.ah = 0x0b; /* Select "Set Color Palette" BIOS routine */
regs.h.bh = 0;
regs.h.bl = (unsigned char) PCX_CGA_BKGND(palettep);
int86(0x10, ®s, ®s); /* Call BIOS video service */
if (vmode != 0x06) /* Select the CGA color palette */
{
/* Check the palette selector bit flag */
sel_flag = PCX_CGA_SELECT(palettep) ? TRUE : FALSE;
/* Check the intensity bit flag */
int_flag = PCX_CGA_INTENSITY(palettep) ? TRUE : FALSE;
/* Determine the CGA palette number */
if (int_flag == TRUE) /* Intensity = bright */
{
if (sel_flag == TRUE)
pal_num = 3; /* Light cyan - light magenta - white */
else
pal_num = 1; /* Cyan - magenta - light grey */
}
else /* Intensity = dim */
{
if (sel_flag == TRUE)
pal_num = 2; /* Light green - light red - yellow */
else
pal_num = 0; /* Green - red - brown */
}
/* Select the foreground color palette */
(void) _selectpalette(pal_num);
}
}
/*
*************************************************************************
*
* PCX_PUT_HERC - Display Hercules PCX Line
*
* Purpose: To copy a decoded PCX image scan line to a Hercules
* monochrome graphics display adapter buffer.
*
* Setup: static void pcx_put_herc
* (
* PCX_WORKBLK *wbp,
* unsigned char _far *linep,
* int line_num
* )
*
* Where: wbp is a PCX image file workblock pointer.
* linep is a PCX scan line buffer pointer.
* line_num is the scan line number.
*
*************************************************************************
*/
void pcx_put_herc
(
PCX_WORKBLK *wbp,
unsigned char _far *linep,
int line_num
)
{
unsigned char _far *displayp; /* Display buffer pointer */
/* Mask off unseen pixels */
linep[wbp->num_bytes - 1] &= wbp->mask;
/* Calculate Hercules display buffer pointer */
displayp = (unsigned char _far *) (0xb0000000L + wbp->page_offset) +
((line_num >> 2) * 90) + 0x2000 * (line_num & 3);
/* Copy data from the scan line buffer to the Hercules display buffer */
(void) _fmemcpy(displayp, linep, wbp->num_bytes);
}
/*
*************************************************************************
*
* PCX_PUT_CGA - Display CGA PCX Line
*
* Purpose: To copy a decoded PCX image scan line to a CGA display
* adapter buffer.
*
* Setup: static void pcx_put_cga
* (
* PCX_WORKBLK *wbp,
* unsigned char _far *linep,
* int line_num
* )
*
* Where: wbp is a PCX image file workblock pointer.
* linep is a PCX scan line buffer pointer.
* line_num is the scan line number.
*
*************************************************************************
*/
static void pcx_put_cga
(
PCX_WORKBLK *wbp,
unsigned char _far *linep,
int line_num
)
{
unsigned char _far *displayp; /* Display buffer pointer */
/* Mask off unseen pixels */
linep[wbp->num_bytes - 1] &= wbp->mask;
/* Calculate CGA display buffer pointer */
displayp = (unsigned char _far *) 0xb8000000L + ((line_num >> 1) * 80)
+ 0x2000 * (line_num & 1);
/* Copy data from the scan line buffer to the CGA display buffer */
(void) _fmemcpy(displayp, linep, wbp->num_bytes);
}
/*
*************************************************************************
*
* PCX_PUT_EGA - Display EGA/VGA PCX Line
*
* Purpose: To copy a decoded PCX image scan line to an EGA/VGA
* display adapter buffer.
*
* Setup: static void pcx_put_ega
* (
* PCX_WORKBLK *wbp,
* unsigned char _far *linep,
* int line_num
* )
*
* Where: wbp is a PCX image file workblock pointer.
* linep is a PCX scan line buffer pointer.
* line_num is the scan line number.
*
*************************************************************************
*/
static void pcx_put_ega
(
PCX_WORKBLK *wbp,
unsigned char _far *linep,
int line_num
)
{
int plane_num; /* EGA/VGA color plane number */
int plane_mask; /* EGA/VGA color plane mask */
unsigned char _far *displayp; /* Display buffer pointer */
/* Calculate buffer pointer */
displayp = (unsigned char _far *) (0xa0000000L + wbp->page_offset) +
line_num * 80;
outpw(0x03ce, 0x0005); /* Select EGA/VGA write mode 0 */
/* Copy PCX scan line data to each color plane */
plane_mask = 0x0100; /* Start with color plane 0 */
for (plane_num = 0; plane_num < (int) wbp->header.nplanes; plane_num++)
{
/* Mask off unseen pixels */
linep[wbp->num_bytes - 1] &= wbp->mask;
outpw(0x03c4, plane_mask + 2); /* Select current color plane */
/* Copy data from the scan line buffer to the EGA/VGA display */
(void) _fmemcpy(displayp, linep, wbp->num_bytes);
linep += wbp->header.bppscan; /* Increment plane offset */
plane_mask <<= 1; /* Sequence plane mask */
}
outpw(0x03c4, 0x0f02); /* Select all color planes */
}
/*
*************************************************************************
*
* PCX_PUT_VGA - Display VGA PCX Line
*
* Purpose: To copy a decoded PCX image scan line to a VGA display
* adapter buffer.
*
* Setup: static void pcx_put_vga
* (
* PCX_WORKBLK *wbp,
* unsigned char _far *linep,
* int line_num
* )
*
* Where: wbp is a PCX image file workblock pointer.
* linep is a PCX scan line buffer pointer.
* line_num is the scan line number.
*
*************************************************************************
*/
static void pcx_put_vga
(
PCX_WORKBLK *wbp,
unsigned char _far *linep,
int line_num
)
{
unsigned char _far *displayp; /* Display buffer pointer */
/* Calculate buffer pointer */
displayp = (unsigned char _far *) 0xa0000000L + line_num * 320;
/* Copy data from the scan line buffer to the VGA display buffer */
(void) _fmemcpy(displayp, linep, wbp->num_bytes);
}