/*
Function: gdImageGifAnimBeginCtx
Like <gdImageGifAnimBegin> except that it outputs to <gdIOCtx>.
See <gdImageGifAnimBegin>.
Parameters:
im - The reference image
out - Pointer to the output <gdIOCtx>.
GlobalCM - Global colormap flag: 1 -> yes, 0 -> no, -1 -> do default
Loops - Loop count; 0 -> infinite, -1 means no loop
Returns:
Nothing.
*/
BGD_DECLARE(void) gdImageGifAnimBeginCtx(gdImagePtr im, gdIOCtxPtr out, int GlobalCM, int Loops)
{
int B;
int RWidth, RHeight;
int Resolution;
int ColorMapSize;
int BitsPerPixel;
int Background = 0;
int i;
/* Default is to use global color map */
if (GlobalCM < 0) {
GlobalCM = 1;
}
BitsPerPixel = colorstobpp(im->colorsTotal);
ColorMapSize = 1 << BitsPerPixel;
RWidth = im->sx;
RHeight = im->sy;
Resolution = BitsPerPixel;
/* Write the Magic header */
gdPutBuf("GIF89a", 6, out);
/* Write out the screen width and height */
gifPutWord(RWidth, out);
gifPutWord(RHeight, out);
/* Indicate that there is a global colour map */
B = GlobalCM ? 0x80 : 0;
/* OR in the resolution */
B |= (Resolution - 1) << 4;
/* OR in the Bits per Pixel */
B |= (BitsPerPixel - 1);
/* Write it out */
gdPutC(B, out);
/* Write out the Background colour */
gdPutC(Background, out);
/* Byte of 0's (future expansion) */
gdPutC(0, out);
/* Write out the Global Colour Map */
if(GlobalCM) {
for(i = 0; i < ColorMapSize; ++i) {
gdPutC(im->red[i], out);
gdPutC(im->green[i], out);
gdPutC(im->blue[i], out);
}
}
if(Loops >= 0) {
gdPutBuf("!\377\13NETSCAPE2.0\3\1", 16, out);
gifPutWord(Loops, out);
gdPutC(0, out);
}
}
static void
GIFEncode(gdIOCtxPtr fp, int GWidth, int GHeight, int GInterlace, int Background, int Transparent, int BitsPerPixel, int *Red, int *Green, int *Blue, gdImagePtr im)
{
int B;
int RWidth, RHeight;
int LeftOfs, TopOfs;
int Resolution;
int ColorMapSize;
int InitCodeSize;
int i;
GifCtx ctx;
memset(&ctx, 0, sizeof(ctx));
ctx.Interlace = GInterlace;
ctx.in_count = 1;
ColorMapSize = 1 << BitsPerPixel;
RWidth = ctx.Width = GWidth;
RHeight = ctx.Height = GHeight;
LeftOfs = TopOfs = 0;
Resolution = BitsPerPixel;
/*
* Calculate number of bits we are expecting
*/
ctx.CountDown = (long)ctx.Width * (long)ctx.Height;
/*
* Indicate which pass we are on (if interlace)
*/
ctx.Pass = 0;
/*
* The initial code size
*/
if( BitsPerPixel <= 1 )
InitCodeSize = 2;
else
InitCodeSize = BitsPerPixel;
/*
* Set up the current x and y position
*/
ctx.curx = ctx.cury = 0;
/*
* Write the Magic header
*/
gdPutBuf(Transparent < 0 ? "GIF87a" : "GIF89a", 6, fp );
/*
* Write out the screen width and height
*/
gifPutWord( RWidth, fp );
gifPutWord( RHeight, fp );
/*
* Indicate that there is a global colour map
*/
B = 0x80; /* Yes, there is a color map */
/*
* OR in the resolution
*/
B |= (Resolution - 1) << 5;
/*
* OR in the Bits per Pixel
*/
B |= (BitsPerPixel - 1);
/*
* Write it out
*/
gdPutC( B, fp );
/*
* Write out the Background colour
*/
gdPutC( Background, fp );
/*
* Byte of 0's (future expansion)
*/
gdPutC( 0, fp );
/*
* Write out the Global Colour Map
*/
for( i=0; i<ColorMapSize; ++i ) {
gdPutC( Red[i], fp );
gdPutC( Green[i], fp );
gdPutC( Blue[i], fp );
}
/*
* Write out extension for transparent colour index, if necessary.
*/
if ( Transparent >= 0 ) {
gdPutC( '!', fp );
gdPutC( 0xf9, fp );
gdPutC( 4, fp );
gdPutC( 1, fp );
gdPutC( 0, fp );
gdPutC( 0, fp );
gdPutC( (unsigned char) Transparent, fp );
gdPutC( 0, fp );
}
/*
* Write an Image separator
*/
gdPutC( ',', fp );
/*
* Write the Image header
*/
gifPutWord( LeftOfs, fp );
gifPutWord( TopOfs, fp );
gifPutWord( ctx.Width, fp );
gifPutWord( ctx.Height, fp );
/*
* Write out whether or not the image is interlaced
*/
if( ctx.Interlace )
gdPutC( 0x40, fp );
else
gdPutC( 0x00, fp );
/*
* Write out the initial code size
*/
gdPutC( InitCodeSize, fp );
/*
* Go and actually compress the data
*/
compress( InitCodeSize+1, fp, im, &ctx );
/*
* Write out a Zero-length packet (to end the series)
*/
gdPutC( 0, fp );
/*
* Write the GIF file terminator
*/
gdPutC( ';', fp );
}
static void GIFAnimEncode(gdIOCtxPtr fp, int IWidth, int IHeight, int LeftOfs, int TopOfs, int GInterlace, int Transparent, int Delay, int Disposal, int BitsPerPixel, int *Red, int *Green, int *Blue, gdImagePtr im)
{
int B;
int ColorMapSize;
int InitCodeSize;
int i;
GifCtx ctx;
memset(&ctx, 0, sizeof(ctx));
ctx.Interlace = GInterlace;
ctx.in_count = 1;
ColorMapSize = 1 << BitsPerPixel;
if(LeftOfs < 0) {
LeftOfs = 0;
}
if(TopOfs < 0) {
TopOfs = 0;
}
if(Delay < 0) {
Delay = 100;
}
if(Disposal < 0) {
Disposal = 1;
}
ctx.Width = IWidth;
ctx.Height = IHeight;
/* Calculate number of bits we are expecting */
ctx.CountDown = (long)ctx.Width * (long)ctx.Height;
/* Indicate which pass we are on (if interlace) */
ctx.Pass = 0;
/* The initial code size */
if(BitsPerPixel <= 1) {
InitCodeSize = 2;
} else {
InitCodeSize = BitsPerPixel;
}
/* Set up the current x and y position */
ctx.curx = ctx.cury = 0;
/* Write out extension for image animation and looping */
gdPutC('!', fp);
gdPutC(0xf9, fp);
gdPutC(4, fp);
gdPutC((Transparent >= 0 ? 1 : 0) | (Disposal << 2), fp);
gdPutC((unsigned char)(Delay & 255), fp);
gdPutC((unsigned char)((Delay >> 8) & 255), fp);
gdPutC((unsigned char) Transparent, fp);
gdPutC(0, fp);
/* Write an Image separator */
gdPutC(',', fp);
/* Write out the Image header */
gifPutWord(LeftOfs, fp);
gifPutWord(TopOfs, fp);
gifPutWord(ctx.Width, fp);
gifPutWord(ctx.Height, fp);
/* Indicate that there is a local colour map */
B = (Red && Green && Blue) ? 0x80 : 0;
/* OR in the interlacing */
B |= ctx.Interlace ? 0x40 : 0;
/* OR in the Bits per Pixel */
B |= (Red && Green && Blue) ? (BitsPerPixel - 1) : 0;
/* Write it out */
gdPutC(B, fp);
/* Write out the Local Colour Map */
if(Red && Green && Blue) {
for(i = 0; i < ColorMapSize; ++i) {
gdPutC(Red[i], fp);
gdPutC(Green[i], fp);
gdPutC(Blue[i], fp);
}
}
/* Write out the initial code size */
gdPutC(InitCodeSize, fp);
/* Go and actually compress the data */
compress(InitCodeSize + 1, fp, im, &ctx);
/* Write out a Zero-length packet (to end the series) */
gdPutC(0, fp);
}
