File: gif2x11.c

package info (click to toggle)
giflib 4.1.6-11%2Bdeb8u1
  • links: PTS, VCS
  • area: main
  • in suites: jessie
  • size: 3,348 kB
  • ctags: 1,501
  • sloc: ansic: 11,188; sh: 9,222; cpp: 907; makefile: 158; sed: 57; perl: 54
file content (563 lines) | stat: -rw-r--r-- 18,514 bytes parent folder | download | duplicates (3)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
/*****************************************************************************
*   "Gif-Lib" - Yet another gif library.				     *
*									     *
* Written by:  Gershon Elber				Ver 0.1, Jul. 1989   *
******************************************************************************
* Program to display GIF file under X11 window system.			     *
* Options:								     *
* -q : quiet printing mode.						     *
* -p PosX PosY : defines the position where to put the image.		     *
* -d Display : what display should go to.				     *
* -f : force attempt to allocate the exact colors. This usually look bad...  *
* -h : on-line help.							     *
******************************************************************************
* History:								     *
* 28 Dec 89 - Version 1.0 by Gershon Elber, color allocation is based on the *
*		xgif program by John Bradley, bradley@cis.ipenn.edu.	     *
*****************************************************************************/

#ifdef HAVE_CONFIG_H
#include <config.h>
#endif

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

#ifdef HAVE_LIBX11
#include <X11/Xlib.h>
#include <X11/Xutil.h>
#include <X11/cursorfont.h>
#endif /* HAVE_LIBX11 */

#ifndef __MSDOS__
#include <stdlib.h>
#endif
#include <stdio.h>
#include <ctype.h>
#include <string.h>
#ifdef HAVE_FCNTL_H
#include <fcntl.h>
#endif /* HAVE_FCNTL_H */
#include "gif_lib.h"
#include "getarg.h"

#define PROGRAM_NAME	"Gif2X11"

#define ICON_SIZE	60
#define ABS(x)		((x) > 0 ? (x) : (-(x)))

#ifdef __MSDOS__
extern unsigned int
    _stklen = 16384;			     /* Increase default stack size. */
#endif /* __MSDOS__ */
#ifdef SYSV
static char *VersionStr =
        "Gif toolkit module,\t\tGershon Elber\n\
	(C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr = "Gif2X11 q%- p%-PosX|PosY!d!d d%-Display!s f%- h%- GifFile!*s";
#else
static char
    *VersionStr =
	PROGRAM_NAME
	GIF_LIB_VERSION
	"	Gershon Elber,	"
	__DATE__ ",   " __TIME__ "\n"
	"(C) Copyright 1989 Gershon Elber.\n";
static char
    *CtrlStr =
	PROGRAM_NAME
	" q%- p%-PosX|PosY!d!d d%-Display!s f%- h%- GifFile!*s";
#endif /* SYSV */

/* Make some variables global, so we could access them faster: */
static int
    PosFlag = FALSE,
    HelpFlag = FALSE,
    DisplayFlag = FALSE,
    ForceFlag = FALSE,
    ColorMapSize = 0,
    BackGround = 0,
    XPosX = 0,
    XPosY = 0,
    InterlacedOffset[] = { 0, 4, 2, 1 }, /* The way Interlaced image should. */
    InterlacedJumps[] = { 8, 8, 4, 2 };    /* be read - offsets and jumps... */
static char
    *DisplayName = NULL;
static ColorMapObject
    *ColorMap;

/* X specific staff goes here. XColorTable will hold the GIF image colors,   */
/* while XPixelTable will hold the pixel number so we can redirect through   */
/* it when forming the image bitmap in X format.			     */
/* Note the table has 256 entry which is the maximum allowed in GIF format.  */
static XColor XColorTable[256];
static unsigned long XPixelTable[256];
static Display *XDisplay;
static int XScreen;
static Window Xroot, XImageWndw;
static Colormap XColorMap;
static GC XGraphContext;
static Visual *XVisual;
static XImage *XImageBuffer;
static Pixmap XIcon;
static Cursor XCursor;

#define BYTESPERPIXEL 4

static void Screen2X(int argc, char **argv, GifRowType *ScreenBuffer,
		     int ScreenWidth, int ScreenHeight);
static void AllocateColors1(void);
static void AllocateColors2(void);

/******************************************************************************
* Interpret the command line and scan the given GIF file.		      *
******************************************************************************/
int main(int argc, char **argv)
{
    int	i, j, Error, NumFiles, ImageNum = 0, Size, Row, Col, Width, Height,
        ExtCode, Count;
    GifRecordType RecordType;
    GifByteType *Extension;
    char **FileName = NULL;
    GifRowType *ScreenBuffer;
    GifFileType *GifFile;

    if ((Error = GAGetArgs(argc, argv, CtrlStr,
		&GifQuietPrint, &PosFlag, &XPosX, &XPosY,
	        &DisplayFlag, &DisplayName, &ForceFlag,
		&HelpFlag, &NumFiles, &FileName)) != FALSE ||
		(NumFiles > 1 && !HelpFlag)) {
	if (Error)
	    GAPrintErrMsg(Error);
	else if (NumFiles > 1)
	    GIF_MESSAGE("Error in command line parsing - one GIF file please.");
	GAPrintHowTo(CtrlStr);
	exit(EXIT_FAILURE);
    }

    if (HelpFlag) {
	fprintf(stderr, "%s", VersionStr);
	GAPrintHowTo(CtrlStr);
	exit(EXIT_SUCCESS);
    }

    if (NumFiles == 1) {
	if ((GifFile = DGifOpenFileName(*FileName)) == NULL) {
	    PrintGifError();
	    exit(EXIT_FAILURE);
	}
    }
    else {
	/* Use the stdin instead: */

#ifdef __MSDOS__
	setmode(0, O_BINARY);
#endif /* __MSDOS__ */
	if ((GifFile = DGifOpenFileHandle(0)) == NULL) {
	    PrintGifError();
	    exit(EXIT_FAILURE);
	}
    }

    /* Lets see if we can get access to the X server before we even start: */
    if ((XDisplay = (Display *) XOpenDisplay(DisplayName)) == NULL)
	GIF_EXIT("Failed to access X server, abored.");
    XScreen = DefaultScreen(XDisplay);
    Xroot = RootWindow(XDisplay, XScreen);
    XColorMap = DefaultColormap(XDisplay, XScreen);
    XGraphContext = DefaultGC(XDisplay, XScreen);
    XVisual = DefaultVisual(XDisplay, XScreen);
    XSetBackground(XDisplay, XGraphContext, BlackPixel(XDisplay, XScreen));
    XSetForeground(XDisplay, XGraphContext, WhitePixel(XDisplay, XScreen));

    /* Allocate the screen as vector of column of rows. We cannt allocate    */
    /* the all screen at once, as this broken minded CPU can allocate up to  */
    /* 64k at a time and our image can be bigger than that:		     */
    /* Note this screen is device independent - its the screen as defined by */
    /* the GIF file parameters itself.					     */
    if ((ScreenBuffer = (GifRowType *)
	malloc(GifFile->SHeight * sizeof(GifRowType *))) == NULL)
	    GIF_EXIT("Failed to allocate memory required, aborted.");

    Size = GifFile->SWidth * sizeof(GifPixelType);/* Size in bytes one row.*/
    if ((ScreenBuffer[0] = (GifRowType) malloc(Size)) == NULL) /* First row. */
	GIF_EXIT("Failed to allocate memory required, aborted.");

    for (i = 0; i < GifFile->SWidth; i++)  /* Set its color to BackGround. */
	ScreenBuffer[0][i] = GifFile->SBackGroundColor;
    for (i = 1; i < GifFile->SHeight; i++) {
	/* Allocate the other rows, and set their color to background too: */
	if ((ScreenBuffer[i] = (GifRowType) malloc(Size)) == NULL)
	    GIF_EXIT("Failed to allocate memory required, aborted.");

	memcpy(ScreenBuffer[i], ScreenBuffer[0], Size);
    }

    /* Scan the content of the GIF file and load the image(s) in: */
    do {
	if (DGifGetRecordType(GifFile, &RecordType) == GIF_ERROR) {
	    PrintGifError();
	    exit(EXIT_FAILURE);
	}
	switch (RecordType) {
	    case IMAGE_DESC_RECORD_TYPE:
		if (DGifGetImageDesc(GifFile) == GIF_ERROR) {
		    PrintGifError();
		    exit(EXIT_FAILURE);
		}
		Row = GifFile->Image.Top; /* Image Position relative to Screen. */
		Col = GifFile->Image.Left;
		Width = GifFile->Image.Width;
		Height = GifFile->Image.Height;
		GifQprintf("\n%s: Image %d at (%d, %d) [%dx%d]:     ",
		    PROGRAM_NAME, ++ImageNum, Col, Row, Width, Height);
		if (GifFile->Image.Left + GifFile->Image.Width > GifFile->SWidth ||
		   GifFile->Image.Top + GifFile->Image.Height > GifFile->SHeight) {
		    fprintf(stderr, "Image %d is not confined to screen dimension, aborted.\n",ImageNum);
		    exit(EXIT_FAILURE);
		}
		if (GifFile->Image.Interlace) {
		    /* Need to perform 4 passes on the images: */
		    for (Count = i = 0; i < 4; i++)
			for (j = Row + InterlacedOffset[i]; j<Row + Height;
						 j += InterlacedJumps[i]) {
			    GifQprintf("\b\b\b\b%-4d", Count++);
			    if (DGifGetLine(GifFile, &ScreenBuffer[j][Col],
				Width) == GIF_ERROR) {
				PrintGifError();
				exit(EXIT_FAILURE);
			    }
			}
		}
		else {
		    for (i = 0; i < Height; i++) {
			GifQprintf("\b\b\b\b%-4d", i);
			if (DGifGetLine(GifFile, &ScreenBuffer[Row++][Col],
				Width) == GIF_ERROR) {
			    PrintGifError();
			    exit(EXIT_FAILURE);
			}
		    }
		}
		break;
	    case EXTENSION_RECORD_TYPE:
		/* Skip any extension blocks in file: */
		if (DGifGetExtension(GifFile, &ExtCode, &Extension) == GIF_ERROR) {
		    PrintGifError();
		    exit(EXIT_FAILURE);
		}
		while (Extension != NULL) {
		    if (DGifGetExtensionNext(GifFile, &Extension) == GIF_ERROR) {
			PrintGifError();
			exit(EXIT_FAILURE);
		    }
		}
		break;
	    case TERMINATE_RECORD_TYPE:
		break;
	    default:		    /* Should be traps by DGifGetRecordType. */
		break;
	}
    }
    while (RecordType != TERMINATE_RECORD_TYPE);

    /* Lets display it - set the global variables required and do it: */
    BackGround = GifFile->SBackGroundColor;
    ColorMap = (GifFile->Image.ColorMap
		? GifFile->Image.ColorMap
		: GifFile->SColorMap);
    if (ColorMap == NULL) {
        fprintf(stderr, "Gif Image does not have a colormap\n");
        exit(EXIT_FAILURE);
    }
    ColorMapSize = ColorMap->ColorCount;
    Screen2X(argc, argv, ScreenBuffer, GifFile->SWidth, GifFile->SHeight);

    for (i = GifFile->SHeight - 1 ; i >= 0 ; i--) {
	free( ScreenBuffer[ i ] );
    }
    free( ScreenBuffer );
    if ( XImageBuffer != (XImage *) NULL )
	XDestroyImage( XImageBuffer );

    if ( XIcon )
	XFreePixmap( XDisplay , XIcon );

    if (DGifCloseFile(GifFile) == GIF_ERROR) {
	PrintGifError();
	exit(EXIT_FAILURE);
    }
    GifQprintf("\n");

	return 0 ;
}

/******************************************************************************
* The real display routine.						      *
******************************************************************************/
static void Screen2X(int argc, char **argv, GifRowType *ScreenBuffer,
		     int ScreenWidth, int ScreenHeight)
{
#define	WM_DELETE_WINDOW	"WM_DELETE_WINDOW"

	Status	rc ;
	Atom	atomKill ;

    int i, j, c, Size, x, y,
        MinIntensity, MaxIntensity, AvgIntensity, IconSizeX, IconSizeY;
    char *XImageData, *XIconData, KeyBuffer[81];
    unsigned long ValueMask;
    GifColorType *ColorMapEntry = ColorMap->Colors;
    XSetWindowAttributes SetWinAttr;
    XSizeHints Hints;
    XEvent Event;
    XExposeEvent *EEvent;
    XKeyEvent *KEvent;
    XComposeStatus Stat;
    KeySym KS;

    /* Let find out what are the intensities in the color map: */
    MaxIntensity = 0;
    MinIntensity = 256 * 100;
    for (i = 0; i < ColorMapSize; i++) {
	c = ColorMapEntry[i].Red * 30 +
	    ColorMapEntry[i].Green * 59 +
	    ColorMapEntry[i].Blue * 11;
	if (c > MaxIntensity) MaxIntensity = c;
	if (c < MinIntensity) MinIntensity = c;
    }
    AvgIntensity = (MinIntensity + MaxIntensity) / 2;

    /* The big trick here is to select the colors so lets do this first: */
    if (ForceFlag)
	AllocateColors2();
    else
	AllocateColors1();

    SetWinAttr.background_pixel = BlackPixel( XDisplay, XScreen );
    SetWinAttr.border_pixel = WhitePixel( XDisplay, XScreen );
    ValueMask = CWBackPixel | CWBorderPixel;

    Hints.flags = PSize | PMinSize | PMaxSize;
    Hints.x = Hints.y = 1;
    Hints.width = Hints.min_width = Hints.max_width = ScreenWidth;
    Hints.height = Hints.min_height = Hints.max_height = ScreenHeight;
    if (PosFlag) {
	Hints.flags |= USPosition;
	Hints.x = XPosX;
	Hints.y = XPosY;
    }

    XImageWndw = XCreateWindow(XDisplay, Xroot, XPosX, XPosY,
			       ScreenWidth, ScreenHeight,
			       1, 0,
			       CopyFromParent, CopyFromParent,
			       ValueMask, &SetWinAttr);

    /* Set up the icon bit map to be a shrinked BW version of the image: */
    if (ScreenWidth > ScreenHeight) {
	IconSizeX = (ICON_SIZE / 8) * 8;
	IconSizeY = (ScreenHeight * ICON_SIZE) / ScreenWidth;
    }
    else {
	IconSizeY = ICON_SIZE;
	IconSizeX = (((ScreenWidth * ICON_SIZE) / ScreenHeight) / 8) * 8;
    }
    XIconData = (char *) malloc(IconSizeX * IconSizeY / 8);
    memset(XIconData, 0, IconSizeX * IconSizeY / 8);
    for (i = 0; i < IconSizeY; i++) {
	y = (i * ScreenHeight / IconSizeY);
	Size = i * IconSizeX / 8;
	for (j = 0; j < IconSizeX; j++) {
	    x = j * ScreenWidth / IconSizeX;
	    c = ScreenBuffer[y][x];
	    c = ColorMapEntry[c].Red * 30 +
		ColorMapEntry[c].Green * 59 +
		ColorMapEntry[c].Blue * 11 > AvgIntensity;
	    XIconData[Size + j / 8] |= c << (j % 8);
	}
    }

    XIcon = XCreateBitmapFromData(XDisplay, XImageWndw, XIconData,
				  IconSizeX, IconSizeY);

    XSetStandardProperties(XDisplay, XImageWndw,
			   PROGRAM_NAME, PROGRAM_NAME, XIcon,
			   argv, argc,
			   &Hints);

    free( XIconData );

    atomKill = XInternAtom(XDisplay, WM_DELETE_WINDOW, False );
    rc = XSetWMProtocols( XDisplay, XImageWndw , &atomKill , 1 );
    if ( rc == 0 )
	GIF_EXIT("Failed to trap WM_DELETE_WINDOW event" );

    XSelectInput(XDisplay, XImageWndw, ExposureMask | KeyPressMask);

    /* Set out own cursor: */
    XCursor = XCreateFontCursor(XDisplay, XC_diamond_cross);
    XDefineCursor(XDisplay, XImageWndw, XCursor);
    
    XMapWindow(XDisplay, XImageWndw);

    /* Create the image in X format: */
    if ((XImageData = (char *) malloc(ScreenWidth * ScreenHeight * BYTESPERPIXEL)) == NULL)
	GIF_EXIT("Failed to allocate memory required, aborted.");

    for (i = 0; i < ScreenHeight; i++) {
	y = i * ScreenWidth;
	for (j = 0; j < ScreenWidth; j++) {
	    XImageData[(y + j)*BYTESPERPIXEL] = XColorTable[ScreenBuffer[i][j]].blue;
	    XImageData[(y + j)*BYTESPERPIXEL+1] = XColorTable[ScreenBuffer[i][j]].green;
	    XImageData[(y + j)*BYTESPERPIXEL+2] = XColorTable[ScreenBuffer[i][j]].red;
    }
    }
    XImageBuffer = XCreateImage(XDisplay, XVisual, DefaultDepth(XDisplay, DefaultScreen(XDisplay)), ZPixmap, 0,
				XImageData, ScreenWidth, ScreenHeight,
                 BitmapPad(XDisplay), ScreenWidth*BYTESPERPIXEL);

    while (TRUE) {
	XNextEvent(XDisplay, &Event);
	switch (Event.type) {
	    case Expose:
	        EEvent = (XExposeEvent *) &Event;
		XPutImage(XDisplay, XImageWndw, XGraphContext, XImageBuffer,
			  EEvent->x, EEvent->y,
			  EEvent->x, EEvent->y,
			  EEvent->width, EEvent->height);
		break;
	    case KeyPress:
	        KEvent = (XKeyEvent *) &Event;
		XLookupString(KEvent, KeyBuffer, 80, &KS, &Stat);
		if (KeyBuffer[0] == 3) return;
	/*	if (KeyBuffer[0] == 3) { free(XImageData ); return; }	made by XDestroyImage	*/
		break;
	    case ClientMessage :
		if ( Event.xclient.data.l[0] == atomKill ) return ;
		break ;
	}
    }
}

/******************************************************************************
* Routine to allocate the requested colors from the X server.		      *
* Colors are allocated until success by stripping off the least bits of the   *
* colors.								      *
******************************************************************************/
static void AllocateColors1(void)
{
    int Strip, Msk, i;
    char Msg[80];

    for (i = 0; i < 256; i++)
	XPixelTable[i] = 0;	   /* Put reasonable color for out of range. */

    for (Strip = 0, Msk = 0xff; Strip < 8; Strip++, Msk <<= 1) {
	for (i = 0; i < ColorMapSize; i++) {
	    /* Prepare color entry in X format. */
	    XColorTable[i].red = (ColorMap->Colors[i].Red & Msk) << 8;
	    XColorTable[i].green = (ColorMap->Colors[i].Green & Msk) << 8;
	    XColorTable[i].blue = (ColorMap->Colors[i].Blue & Msk) << 8;
	    XColorTable[i].flags = DoRed | DoGreen | DoBlue;
	    if (XAllocColor(XDisplay, XColorMap, &XColorTable[i]))
		XPixelTable[i] = XColorTable[i].pixel;
	    else
		break;
	}
	if (i < ColorMapSize)
	    XFreeColors(XDisplay, XColorMap, XPixelTable, i, 0L);
	else
	    break;
    }

    if (Strip == 8)
	GIF_EXIT("Can not display the image - not enough colors available.");

    if (Strip != 0) {
	sprintf(Msg, "%d bits were stripped off the color map.", Strip);
	GIF_MESSAGE(Msg);
    }
}

/******************************************************************************
* Routine to allocate the requested colors from the X server.		      *
* Two stages are performed:						      *
* 1. Colors are requested directly.					      *
* 2. If not enough colors can be allocated, the closest current color	      *
*    in current table is selected instead.				      *
* This allocation is not optimal as when fail to allocate all colors one      *
* should pick the right colors to do allocate in order to minimize the        *
* closest distance from the unallocated ones under some norm (what is a good  *
* norm for the RGB space?). Improve it if you are bored.		      *
******************************************************************************/
static void AllocateColors2(void)
{
    int i, j, Index = 0, Count = 0, XNumOfColors;
    char Msg[80];
    unsigned long D, Distance, AvgDistance = 0, Red, Green, Blue;
    GifBooleanType Failed = FALSE;
    XColor *XOldColorTable;

    for (i = 0; i < 256; i++) {
	if (i < ColorMapSize) {          /* Prepere color entry in X format. */
	    XColorTable[i].red = ColorMap->Colors[i].Red << 8;
	    XColorTable[i].green = ColorMap->Colors[i].Green << 8;
	    XColorTable[i].blue = ColorMap->Colors[i].Blue << 8;
	    XColorTable[i].flags = DoRed | DoGreen | DoBlue;
	    XPixelTable[i] = -1;		       /* Not allocated yet. */
	}
	else
	    XPixelTable[i] = 0;    /* Put reasonable color for out of range. */
    }

    for (i = 0; i < ColorMapSize; i++)	      /* Allocate the colors from X: */
	if (XAllocColor(XDisplay, XColorMap, &XColorTable[i]))
	    XPixelTable[i] = XColorTable[i].pixel;
	else
	    Failed = TRUE;

    if (Failed) {
	XNumOfColors = DisplayCells(XDisplay, XScreen);
	XOldColorTable = (XColor *) malloc(sizeof(XColor) * XNumOfColors);
	for (i = 0; i < XNumOfColors; i++) XOldColorTable[i].pixel = i;
	XQueryColors(XDisplay, XColorMap, XOldColorTable, XNumOfColors);
	
	for (i = 0; i < ColorMapSize; i++) {
	    /* Allocate closest colors from X: */
	    if (XPixelTable[i] == -1) {      /* Failed to allocate this one. */
		Distance = 0xffffffff;

		Red = XColorTable[i].red;
		Green = XColorTable[i].green;
		Blue = XColorTable[i].blue;

		for (j = 0; j < XNumOfColors; j++) {
		    /* Find the closest color in 3D RGB space using L1 norm. */
		    if ((D = ABS(Red - XOldColorTable[j].red) +
			     ABS(Green - XOldColorTable[j].green) +
			     ABS(Blue - XOldColorTable[j].blue)) < Distance) {
			Distance = D;
			Index = j;
		    }
		}
	        XPixelTable[i] = Index;

		AvgDistance += Distance;
		Count++;
	    }
	}
	free(XOldColorTable);

	sprintf(Msg, "Colors will be approximated (average error = %ld).\n",
		AvgDistance / Count);
	GIF_MESSAGE(Msg);
    }
}