void GifDecode(FILE *fp, UBYTE *pix, GifImageHdr gifimage)
{ UBYTE *chPos, firstCodeOut = 0, charBuff[256];
ULONG CLEAR, EOI, bits = 0, code = 0, codeFeched, buffCount = 0;
int need = 0;
interlaced = gifimage.i;
imgwidth = gifimage.width;
imgheight = gifimage.height;
imgsize = imgwidth * imgheight;
picture = pix;
pass = picI = 0;
if ( debugFlag > 1 )
fprintf(stderr, "(interlaced,imgwidth,imgheight,imgsize)=(%d,%d,%d,%d)\n",
interlaced, imgwidth, imgheight, imgsize);
rootCodeSize = Xgetc(fp);
CLEAR = 1 << rootCodeSize;
EOI = CLEAR + 1;
GifClearTable();
if ( (buffCount = Xgetc(fp)) == 0 ) {
sprintf(charBuff, "End of image # %d before it began!\n", count);
TheEnd1(charBuff);
}
while(buffCount > 0) {
if ( fread(charBuff, 1, buffCount, fp) != buffCount ) {
sprintf(charBuff, "Premature end of file; Image # %d\n", count);
TheEnd1(charBuff);
}
for(chPos = charBuff; buffCount-- > 0; chPos++) {
need += (int) *chPos << bits;
bits += 8;
while (bits >= codeSize) {
code = need & mask;
need >>= codeSize;
bits -= codeSize;
if(code > expected)
TheEnd1("Neither LZW nor RunLength (new code != expected)\n");
if (code == EOI) {
if (debugFlag > 1) fprintf(stderr, "Image # %d ends; buffCount=%d\n",
count, buffCount);
goto skipRest;
}
if(code == CLEAR) {
GifClearTable();
continue;
}
if(old == MAXVAL) { /* i.e. first code after clear table */
pix = GifSendData(pix, 1, &last[code]);
firstCodeOut = last[code];
old = code;
continue;
}
codeFeched = code;
if(code == expected) {
*topGifBuff++ = firstCodeOut;
code = old;
}
while(code > CLEAR) {
*topGifBuff++ = last[code];
code = first[code];
}
*topGifBuff++ = firstCodeOut = last[code];
first[expected] = old;
last[expected] = firstCodeOut;
if(expected < MAXVAL) expected++;
if(((expected & mask) == 0) && (expected < MAXVAL)) {
codeSize++;
mask += expected;
}
old = codeFeched;
pix = GifSendData(pix, topGifBuff - gifBuff, gifBuff);
topGifBuff = gifBuff;
} /* end of extracting codes */
} /* end of reading a block of data */
if ( (buffCount = Xgetc(fp)) == 0 ) {
sprintf(charBuff, "End of image # %d without EOI\n", count);
TheEnd1(charBuff);
}
}
skipRest:
if (debugFlag) fprintf(stderr, "Ending GifDecode, written: %d=%d\n",
interlaced && (pix-picture == 0) ? imgsize : pix - picture, imgsize);
return ;
}
/*
* Read a Gif file.
*/
void animate_gif(FILE *fout,char *fname,int firstImage,int Xoff,int Yoff,
int delay_time,int loop_val) /* time in 100th of seconds */
{
FILE *fp;
UBYTE *pix;
int i;
if ( (fp = fopen(fname, REABIN)) == 0) {
fprintf(stderr, "Can't open %s for reading.\n", fname);
TheEnd();
}
global.trans.type = TRANS_NONE;
global.trans.valid = 0;
global.time = delay_time;
global.disposal = DEFAULT_DISPOSAL;
global.left = Xoff;
global.top = Yoff;
loop=loop_val;
/* loop = TRUE; */
/* loopcount = 0; */
/*global.left = global.top = 0;*/
GifScreenHeader(fp, fout, firstImage);
/* read until , separator */
do {
switch ( i = Xgetc(fp)) {
case ',':
case '\0':
break;
case '!':
Xgetc(fp); /* the extension code */
for ( i = Xgetc(fp); i > 0; i-- ) Xgetc(fp);
while ( ( i = Xgetc(fp) ) > 0 ) {
for ( i = i ; i > 0; i-- ) Xgetc(fp);
}
break;
default:
fclose(fp);
if ( feof(fp) || i == ';' )
TheEnd1("GifReadHeader: Unexpected End of File\n");
TheEnd1("GifReadHeader: Unknown block type\n");
}
} while(i != ',');
if(firstImage) {
globscrn.m = gifscrn.m;
globscrn.pixbits = gifscrn.pixbits;
globscrn.bc = gifscrn.bc;
if ( globscrn.m ) {
for (i = gifMask[1+globscrn.pixbits]; i >= 0; i--) {
gifGmap[i].cmap.red = gifCmap[i].cmap.red;
gifGmap[i].cmap.green = gifCmap[i].cmap.green;
gifGmap[i].cmap.blue = gifCmap[i].cmap.blue;
}
}
if(loop) GifLoop(fout, loopcount);
}
ReadImageHeader(fp);
/*** ACTION for IMAGE */
if ( ( gifimage.m != 0 && globmap !=0 ) || minimize !=0 ) {
UBYTE translator[256], *p, *po;
int left, right=0, top, bot=0, i, j, k, l, hi, wi;
long dsquare, dsquare1;
hi = gifimage.height;
wi = gifimage.width;
if (( pix = (UBYTE *)malloc(wi * hi * sizeof(UBYTE)) ) == NULL )
TheEnd1("No memory for image\n");
if (debugFlag) fprintf(stderr, " decoding picture no %d\n", count);
GifDecode(fp, pix, gifimage);
gifimage.i = 0;
k = gifMask[1+globscrn.pixbits];
l = gifMask[1+gifscrn.pixbits];
for (j = 0; j <= l; j++) {
dsquare = 256*256*3;
for (i = 0; i <= k; i++) {
dsquare1 = sq(gifGmap[i].cmap.red, gifCmap[j].cmap.red) +
sq(gifGmap[i].cmap.green, gifCmap[j].cmap.green) +
sq(gifGmap[i].cmap.blue, gifCmap[j].cmap.blue);
if ( dsquare1 < dsquare ) {
dsquare = dsquare1;
translator[j]=i;
if ( dsquare == 0 ) break;
}
}
}
gifimage.m = 0;
gifscrn.pixbits = globscrn.pixbits;
if (debugFlag) fprintf(stderr, " translating picture no %d\n", count);
for (i = wi * hi -1; i>=0; i--)
pix[i]=translator[pix[i]];
if ( minimize != 0 && pixold != NULL && hi == gifimageold.height
&& wi == gifimageold.width && gifimage.top == gifimageold.top
&& gifimage.left == gifimageold.left ) {
gifimageold = gifimage;
/* First test from left to right, top to bottom */
p = pix; po = pixold;
for (i = 0; i < hi; i++ ) {
for (j = 0; j < wi; j++ ) {
if ( *p++ != *po++ ) {
left = j; top=i;
goto done;
}
}
}
if (FALSE) {
done: /* i.e. a preliminary left and top found */ ;
}
else goto alike; /* writes full image, should we drop it ? */
/* Then test from right to left, bottom to top */
k=hi*wi-1;
p = &pix[k]; po = &pixold[k];
for (i = hi-1; i >= top; i-- ) {
for (j = wi -1; j >= 0; j-- ) {
if ( *p-- != *po-- ) {
right = j; bot=i;
goto botfound;
}
}
}
botfound:
/* The form of the differing area (not rectangle) may be slanted */
if ( right < left ) {
i = right; right = left; left = i;
}
/* Now test between top and bottom at the left hand side */
for (i = top+1; i <= bot; i++ ) {
k= i * wi;
p = &pix[k]; po = &pixold[k];
for (j = 0; j < left; j++ ) {
if ( *p++ != *po++ ) {
left = j;
break;
}
}
}
/* Finally test between bottom and top at the right hand side */
for (i = bot-1; i >= top; i-- ) {
k= (i+1) * wi-1;
p = &pix[k]; po = &pixold[k];
for (j = wi-1; j > right; j-- ) {
if ( *p-- != *po-- ) {
right = j;
break;
}
}
}
gifimage.left += left;
gifimage.top += top;
gifimage.width = right-left+1;
gifimage.height = bot-top+1;
WriteImageHeader(fout);
/* The rectangle containing diffs is transferred to the mem area of pixold */
po = pixold;
for (i = top; i <= bot; i++ ) {
p = &pix[i * wi+left];
for (j = left; j <= right; j++ ) {
*po++ = *p++;
}
}
GifEncode(fout, pixold, gifscrn.pixbits+1, gifimage.height * gifimage.width);
if (debugFlag)
fprintf(stderr, " encoded: width= %d, height = %d, left = %d, top = %d\n",
gifimage.width, gifimage.height, gifimage.left, gifimage.top);
}
else {
alike:
WriteImageHeader(fout);
gifimageold = gifimage;
GifEncode(fout, pix, gifscrn.pixbits+1, gifimage.height * gifimage.width);
if (debugFlag) fprintf(stderr, " picture re-encoded\n");
}
free(pixold);
pixold = pix;
fputc(0, fout); /* block count of zero */
}
else {
WriteImageHeader(fout);
i = Xgetc(fp); fputc(i, fout); /* the LZW code size */
while ( ( gifBlockSize = Xgetc(fp) ) > 0 ) {
fputc(gifBlockSize, fout);
while ( gifBlockSize-- > 0 ) fputc(Xgetc(fp),fout);
}
if ( gifBlockSize == 0 ) fputc(gifBlockSize, fout);
else TheEnd1("GifPassing: Unexpected End of File\n");
}
fclose(fp);
}
