/*****************************************************************************
*   "Gif-Lib" - Yet another gif library.				     *
*									     *
* Written by:  Gershon Elber			IBM PC Ver 1.1,	Jun. 1989    *
******************************************************************************
* Module to dump graphic devices into a GIF file. Current supported devices: *
* 1. EGA, VGA, SVGA (800x600), Hercules on the IBM PC (#define __MSDOS__).   *
* 2. SGI 4D Irix using gl library (#define __SGI_GL__).			     *
* 3. X11 using libX.a (#define __X11__).				     *
******************************************************************************
* History:								     *
* 22 Jun 89 - Version 1.0 by Gershon Elber.				     *
* 12 Aug 90 - Version 1.1 by Gershon Elber (added devices).		     *
*****************************************************************************/

#ifdef __MSDOS__
#include <dos.h>
#include <alloc.h>
#include <graphics.h>
#endif /* __MSDOS__ */

#ifdef __SGI_GL__
#include <gl/gl.h>
#endif /* __SGI_GL__ */

#ifdef __X11__
#include <X11/Xlib.h>
#endif /* __X11__ */

#include <stdio.h>
#include "gif_lib.h"

#define PROGRAM_NAME	"GIF_LIBRARY"

#define SVGA_SPECIAL	999		       /* 800 by 600 Super VGA mode. */

static int GraphDriver = -1,       /* Device parameters - reasonable values. */
	   GraphMode = -1,
	   ScreenColorBits = 1;
static long ScreenXMax = 100,
	    ScreenYMax = 100;
static unsigned int ScreenBase;

#ifdef SYSV
static char *VersionStr =
        "Gif library module,\t\tGershon Elber\n\
	(C) Copyright 1989 Gershon Elber, Non commercial use only.\n";
#else
static char *VersionStr =
	PROGRAM_NAME
	"	IBMPC "
	GIF_LIB_VERSION
	"	Gershon Elber,	"
	__DATE__ ",   " __TIME__ "\n"
	"(C) Copyright 1989 Gershon Elber, Non commercial use only.\n";
#endif /* SYSV */

#if defined(__SGI_GL__) || defined(__X11__)
    GifByteType *GlblGifBuffer = NULL, *GlblGifBufferPtr = NULL;
#endif /* __SGI_GL__ || __X11__ */

#ifdef __SGI_GL__
static int QuantizeRGBBuffer(int Width, int Height, long *RGBBuffer,
			     GifColorType *ColorMap, GifByteType *GIFBuffer);
#endif /* __SGI_GL__ */

static void GetScanLine(GifPixelType *ScanLine, int Y);
static int HandleGifError(GifFileType *GifFile);

/******************************************************************************
* Dump the given Device, into given File as GIF format:			      *
* Return 0 on success, -1 if device not supported, or GIF-LIB error number.   *
* Device is selected via the ReqGraphDriver. Device mode is selected via      *
* ReqGraphMode1/2 as follows:						      *
* 1. IBM PC Hercules card: HERCMONO (one mode only) in ReqGraphMode1,	      *
*    ReqGraphMode2/3 are ignored.					      *
* 2. IBM PC EGA card: EGALO/EGAHI in ReqGraphMode1,			      *
*    ReqGraphMode2/3 are ignored.					      *
* 3. IBM PC EGA64 card: EGA64LO/EGA64HI in ReqGraphMode1,		      *
*    ReqGraphMode2/3 are ignored.					      *
* 4. IBM PC EGAMONO card: EGAMONOHI (one mode only) in ReqGraphMode1,	      *
*    ReqGraphMode2/3 are ignored.					      *
* 5. IBM PC VGA card: VGALO/VGAMED/VGAHI in ReqGraphMode1,		      *
*    ReqGraphMode2/3 are ignored.					      *
* 6. IBM PC SVGA card: ReqGraphMode1/2 are both ignored. Fixed mode (800x600  *
*    16 colors) is assumed.						      *
* 7. SGI 4D using GL: window id to dump (as returned by winget()) in	      *
*    ReqGraphMode1, ReqGraphMode2/3 are ignored.			      *
* 8. X11: Window id in ReqGraphMode1, Display id in ReqGraphMode2, Color      *
*    map id in  ReqGraphMode3.						      *
******************************************************************************/
int DumpScreen2Gif(char *FileName, int ReqGraphDriver, int ReqGraphMode1,
	       					       int ReqGraphMode2,
	       					       int ReqGraphMode3)
{
    int i, j, k;
    GifPixelType *ScanLine;
    GifFileType *GifFile;
    GifColorType *ColorMap = NULL;
#ifdef __MSDOS__
    static GifColorType MonoChromeColorMap[] = {
    	{ 0, 0, 0 },
    	{ 255, 255, 255 }
    };
    /* I have no idea what default EGA64 (4 colors) should be (I guessed...).*/
    static GifColorType EGA64ColorMap[] = {
    	{   0,   0,   0 },   /* 0. Black */
    	{ 255,   0,   0 },   /* 1. Red */
    	{   0, 255,   0 },   /* 2. Green */
    	{   0,   0, 255 },   /* 3. Blue */
    };
    static GifColorType EGAColorMap[] = {
    	{   0,   0,   0 },   /* 0. Black */
    	{   0,   0, 170 },   /* 1. Blue */
    	{   0, 170,   0 },   /* 2. Green */
    	{   0, 170, 170 },   /* 3. Cyan */
    	{ 170,   0,   0 },   /* 4. Red */
    	{ 170,   0, 170 },   /* 5. Magenta */
    	{ 170, 170,   0 },   /* 6. Brown */
    	{ 170, 170, 170 },   /* 7. LightGray */
    	{  85,  85,  85 },   /* 8. DarkGray */
    	{  85,  85, 255 },   /* 9. LightBlue */
    	{  85, 255,  85 },   /* 10. LightGreen */
    	{  85, 255, 255 },   /* 11. LightCyan */
    	{ 255,  85,  85 },   /* 12. LightRed */
    	{ 255,  85, 255 },   /* 13. LightMagenta */
    	{ 255, 255,  85 },   /* 14. Yellow */
    	{ 255, 255, 255 },   /* 15. White */
    };
#endif /* __MSDOS__ */
#if defined(__SGI_GL__) || defined(__X11__)
    long *RGBBuffer;
    GifColorType ColorMap256[256];
#endif
#ifdef __X11__
    XImage *XImg;
    unsigned long XPixel;
    XColor XColorTable[256];			   /* Up to 256 colors in X. */
    XWindowAttributes WinAttr;
#endif /* __X11__ */

    switch (ReqGraphDriver) {		 /* Return on non supported screens. */
#ifdef __MSDOS__
        case HERCMONO:
	    ScreenXMax = 720;
	    ScreenYMax = 350;
	    ScreenColorBits = 1;
	    ScreenBase = 0xb000;
	    ColorMap = MonoChromeColorMap;
	    break;
	case EGA:
	    switch (ReqGraphMode1) {
    	        case EGALO:
		    ScreenYMax = 200;
		    break;
    	        case EGAHI:
		    ScreenYMax = 350;
		    break;
		default:
    	            return -1;
	    }
	    ScreenXMax = 640;
	    ScreenColorBits = 4;
	    ScreenBase = 0xa000;
	    ColorMap = EGAColorMap;
	    break;
	case EGA64:
	    switch (ReqGraphMode1) {
    	        case EGA64LO:
		    ScreenYMax = 200;
		    break;
    	        case EGA64HI:
		    ScreenYMax = 350;
		    break;
		default:
    	            return -1;
	    }
	    ScreenXMax = 640;
	    ScreenColorBits = 2;
	    ScreenBase = 0xa000;
	    ColorMap = EGA64ColorMap;
	    break;
	case EGAMONO:
	    switch (ReqGraphMode1) {
    	        case EGAMONOHI:
		    ScreenYMax = 350;
		    break;
		default:
    	            return -1;
	    }
	    ScreenXMax = 640;
	    ScreenColorBits = 1;
	    ScreenBase = 0xa000;
	    ColorMap = MonoChromeColorMap;
	    break;
	case VGA:
	    switch (ReqGraphMode1) {
    	        case VGALO:
		    ScreenYMax = 200;
		    break;
    	        case VGAMED:
		    ScreenYMax = 350;
		    break;
    	        case VGAHI:
		    ScreenYMax = 480;
		    break;
		default:
    	            return -1;
	    }
	    ScreenXMax = 640;
	    ScreenColorBits = 4;
	    ScreenBase = 0xa000;
	    ColorMap = EGAColorMap;
	    break;
        case SVGA_SPECIAL:
	    ScreenXMax = 800;
	    ScreenYMax = 600;
	    ScreenColorBits = 4;
	    ScreenBase = 0xa000;
	    ColorMap = EGAColorMap;
	    break;
#endif /* __MSDOS__ */
#ifdef __SGI_GL__
	case GIF_DUMP_SGI_WINDOW:
	    winset(ReqGraphMode1);        /* Select window as active window. */
	    getsize(&ScreenXMax, &ScreenYMax);

	    RGBBuffer = (long *) malloc(sizeof(long) * ScreenXMax * ScreenYMax);
	    readsource(SRC_FRONT);
	    if (lrectread((short) 0,
			  (short) 0,
			  (short) (ScreenXMax - 1),
			  (short) (ScreenYMax - 1), RGBBuffer) !=
		ScreenXMax * ScreenYMax) {		        /* Get data. */
		free(RGBBuffer);
		return -1;
	    }
	    GlblGifBuffer = (GifByteType *) malloc(sizeof(GifByteType) *
						ScreenXMax * ScreenYMax);
	    i = QuantizeRGBBuffer(ScreenXMax, ScreenYMax, RGBBuffer,
				  ColorMap256, GlblGifBuffer);
	    /* Find minimum color map size to hold all quantized colors. */
	    for	(ScreenColorBits = 1;
		 (1 << ScreenColorBits) < i && ScreenColorBits < 8;
		 ScreenColorBits++);

	    /* Start to dump with top line as GIF expects it. */
	    GlblGifBufferPtr = GlblGifBuffer + ScreenXMax * (ScreenYMax - 1);
	    ColorMap = ColorMap256;
	    free(RGBBuffer);
	    break;
#endif /* __SGI_GL__ */
#ifdef __X11__
	case GIF_DUMP_X_WINDOW:
	    XGetWindowAttributes((Display *) ReqGraphMode2,
				 (Window) ReqGraphMode1,
				 &WinAttr);
	    ScreenXMax = WinAttr.width;
	    ScreenYMax = WinAttr.height;

	    XImg = XGetImage((Display *) ReqGraphMode2,
			     (Window) ReqGraphMode1,
			     0, 0, ScreenXMax - 1, ScreenYMax - 1,
			     AllPlanes, XYPixmap);

	    GlblGifBuffer = (GifByteType *) malloc(sizeof(GifByteType) *
						ScreenXMax * ScreenYMax);

	    /* Scan the image for all different colors exists. */
	    for (i = 0; i < 256; i++) XColorTable[i].pixel = 0;
	    k = FALSE;
 	    for (i = 0; i < ScreenXMax; i++)
		for (j = 0; j < ScreenYMax; j++) {
		    XPixel = XGetPixel(XImg, i, j);
		    if (XPixel > 255) {
			if (!k) {
			    /* Make sure we state it once only.*/
			    fprintf(stderr, "X Color table - truncated.\n");
			    k = TRUE;
			}
			XPixel = 255;
		    }
		    XColorTable[XPixel].pixel = XPixel;
		}
	    /* Find the RGB representation of the colors. */
	    XQueryColors((Display *) ReqGraphMode2,
			 (Colormap) ReqGraphMode3,
			 XColorTable,
			 256);
	    /* Count number of active colors (Note color 0 is always in)    */
	    /* and create the Gif color map from it.			    */
	    ColorMap = ColorMap256;
	    ColorMap[0].Red = ColorMap[0].Green = ColorMap[0].Blue = 0;
	    for (i = j = 1; i < 256; i++)
		if (XColorTable[i].pixel) {
		    ColorMap[j].Red = XColorTable[i].red / 256;
		    ColorMap[j].Green = XColorTable[i].green / 256;
		    ColorMap[j].Blue = XColorTable[i].blue / 256;
		    /* Save the X color index into the Gif table: */
		    XColorTable[i].pixel = j++;
		}
	    /* and set the number of colors in the Gif color map. */
	    for	(ScreenColorBits = 1;
		 (1 << ScreenColorBits) < j && ScreenColorBits < 8;
		 ScreenColorBits++);

	    /* Prepare the Gif image buffer as indices into the Gif color   */
	    /* map from the X image.					    */
	    GlblGifBufferPtr = GlblGifBuffer;
	    for (i = 0; i < ScreenXMax; i++)
		for (j = 0; j < ScreenYMax; j++)
		    *GlblGifBufferPtr++ =
			XColorTable[XGetPixel(XImg, j, i) & 0xff].pixel;
	    XDestroyImage(XImg);

	    GlblGifBufferPtr = GlblGifBuffer;
	    ColorMap = ColorMap256;
	    break;
#endif /* __X11__ */
	default:
	    return -1;
    }

    ScanLine = (GifPixelType *) malloc(sizeof(GifPixelType) * ScreenXMax);

    GraphDriver = ReqGraphDriver;
    GraphMode = ReqGraphMode1;

    if ((GifFile = EGifOpenFileName(FileName, FALSE)) == NULL ||
	EGifPutScreenDesc(GifFile, ScreenXMax, ScreenYMax, ScreenColorBits,
			  0, ScreenColorBits, ColorMap) == GIF_ERROR ||
	EGifPutImageDesc(GifFile, 0, 0, ScreenXMax, ScreenYMax, FALSE, 1,
			 NULL) == GIF_ERROR) {
	free((char *) ScanLine);
#if defined(__SGI_GL__) || defined(__X11__)
	free((char *) GlblGifBuffer);
#endif
	return HandleGifError(GifFile);
    }

    for (i = 0; i < ScreenYMax; i++) {
	GetScanLine(ScanLine, i);
	if (EGifPutLine(GifFile, ScanLine, ScreenXMax) == GIF_ERROR) {
	    free((char *) ScanLine);
#if defined(__SGI_GL__) || defined(__X11__)
	    free((char *) GlblGifBuffer);
#endif
	    return HandleGifError(GifFile);
	}
    }

    if (EGifCloseFile(GifFile) == GIF_ERROR) {
	free((char *) ScanLine);
#if defined(__SGI_GL__) || defined(__X11__)
	free((char *) GlblGifBuffer);
#endif
	return HandleGifError(GifFile);
    }

    free((char *) ScanLine);
#if defined(__SGI_GL__) || defined(__X11__)
    free((char *) GlblGifBuffer);
#endif
    return 0;
}

#ifdef __SGI_GL__
/******************************************************************************
* Quantize the given 24 bit (8 per RGB) into 256 colors.		      *
******************************************************************************/
static int QuantizeRGBBuffer(int Width, int Height, long *RGBBuffer,
			      GifColorType *ColorMap, GifByteType *GIFBuffer)
{
    int i;
    GifByteType *RedInput, *GreenInput, *BlueInput;

    /* Convert the RGB Buffer into 3 seperated buffers: */
    RedInput = (GifByteType *) malloc(sizeof(GifByteType) * Width * Height);
    GreenInput = (GifByteType *) malloc(sizeof(GifByteType) * Width * Height);
    BlueInput = (GifByteType *) malloc(sizeof(GifByteType) * Width * Height);

    for (i = 0; i < Width * Height; i++) {
	RedInput[i] = RGBBuffer[i] & 0xff;
	GreenInput[i] = (RGBBuffer[i] >> 8) & 0xff;
	BlueInput[i] = (RGBBuffer[i] >> 16) & 0xff;
    }
    for (i = 0; i < 256; i++)
	ColorMap[i].Red = ColorMap[i].Green = ColorMap[i].Blue = 0;

    i = 256;
    QuantizeBuffer(Width, Height, &i,
		   RedInput, GreenInput, BlueInput,
		   GIFBuffer, ColorMap);

    free(RedInput);
    free(GreenInput);
    free(BlueInput);

    return i;			   /* Real number of colors in color table. */
}
#endif /* __SGI_GL__ */

/******************************************************************************
* Update the given scan line buffer with the pixel levels of the Y line.      *
* This routine is device specific, so make sure you know was you are doing    *
******************************************************************************/
static void GetScanLine(GifPixelType *ScanLine, int Y)
{
    unsigned char ScreenByte;
    int i, j, k;
    unsigned int BufferOffset, Bit;
#ifdef __MSDOS__
    union REGS InRegs, OutRegs;
#endif /* __MSDOS__ */

    switch (GraphDriver) {
#ifdef __MSDOS__
	case HERCMONO:
	    BufferOffset = 0x2000 * (Y % 4) + (Y / 4) * (ScreenXMax / 8);
	    /* In one scan lines we have ScreenXMax / 8 bytes: */
	    for (i = 0, k = 0; i < ScreenXMax / 8; i++) {
		ScreenByte = (unsigned char) peekb(ScreenBase, BufferOffset++);
		for (j = 0, Bit = 0x80; j < 8; j++) {
		    ScanLine[k++] = (ScreenByte & Bit ? 1 : 0);
		    Bit >>= 1;
		}
	    }
	    break;
	case EGA:
	case EGA64:
	case EGAMONO:
	case VGA:
	case SVGA_SPECIAL:
	    InRegs.x.dx = Y;
	    InRegs.h.bh = 0;
    	    InRegs.h.ah = 0x0d;				   /* BIOS Read dot. */
	    for (i = 0; i < ScreenXMax; i++) {
	    	InRegs.x.cx = i;
		int86(0x10, &InRegs, &OutRegs);
	    	ScanLine[i] = OutRegs.h.al;
	    }

	    /* Makr this line as done by putting a xored dot on the left. */
	    InRegs.x.dx = Y;
	    InRegs.h.bh = 0;
	    InRegs.h.ah = 0x0c;		       /* BIOS Write dot (xor mode). */
	    InRegs.h.al = 0x81;			        /* Xor with color 1. */
	    InRegs.x.cx = 0;
	    int86(0x10, &InRegs, &OutRegs);
	    InRegs.x.dx = Y;
	    InRegs.h.bh = 0;
	    InRegs.h.ah = 0x0c;		       /* BIOS Write dot (xor mode). */
	    InRegs.h.al = 0x81;			        /* Xor with color 1. */
	    InRegs.x.cx = 1;
	    int86(0x10, &InRegs, &OutRegs);

	    if (Y == ScreenYMax - 1) {/* Last row - clear all marks we made. */
		for (i = 0; i < ScreenYMax; i++) {
		    InRegs.h.bh = 0;
		    InRegs.h.ah = 0x0c;	       /* BIOS Write dot (xor mode). */
		    InRegs.h.al = 0x81;		   /* Xor back with color 1. */
		    InRegs.x.dx = i;
		    InRegs.x.cx = 0;
		    int86(0x10, &InRegs, &OutRegs);
		    InRegs.h.bh = 0;
		    InRegs.h.ah = 0x0c;	       /* BIOS Write dot (xor mode). */
		    InRegs.h.al = 0x81;		   /* Xor back with color 1. */
		    InRegs.x.dx = i;
		    InRegs.x.cx = 1;
		    int86(0x10, &InRegs, &OutRegs);
                }
	    }
	    break;
#endif /* __MSDOS__ */
#ifdef __SGI_GL__
	case GIF_DUMP_SGI_WINDOW:
	    memcpy(ScanLine, GlblGifBufferPtr, ScreenXMax * sizeof(GifPixelType));
	    GlblGifBufferPtr -= ScreenXMax;
	    break;
#endif /* __SGI_GL__ */
#ifdef __X11__
	case GIF_DUMP_X_WINDOW:
	    memcpy(ScanLine, GlblGifBufferPtr, ScreenXMax * sizeof(GifPixelType));
	    GlblGifBufferPtr += ScreenXMax;
	    break;
#endif /* __X11__ */
	default:
	    break;
    }
}

/******************************************************************************
* Handle last GIF error. Try to close the file and free all allocated memory. *
******************************************************************************/
static int HandleGifError(GifFileType *GifFile)
{
    int i = GifLastError();

    if (EGifCloseFile(GifFile) == GIF_ERROR) {
	GifLastError();
    }
    return i;
}