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https://github.com/zint/zint
synced 2024-11-16 20:57:25 +13:00
Add 10 colours plus transparency ("T") to gif export.
This commit is contained in:
Harald Oehlmann
parent
d20c6b6b78
commit
327d6ec88b
@ -47,10 +47,10 @@
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/* Index of transparent color, -1 for no transparent color
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* This might be set into a variable if transparency is activated as an option
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*/
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#define TRANSPARENT_INDEX (-1)
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#define TRANSPARENT_INDEX (15)
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/* Used bit depth, may be changed for bigger pallet in future */
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#define DESTINATION_IMAGE_BITS 1
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/* Used bit depth: 10 value pallet is 4 bit */
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#define DESTINATION_IMAGE_BITS 4
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#include <stdlib.h>
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typedef struct s_statestruct {
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@ -69,6 +69,30 @@ typedef struct s_statestruct {
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unsigned char NodePix[4096];
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} statestruct;
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/* Transform a Pixel to a lzw colourmap index.
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* See the 16 entries colour map definition in the code at the end for the mapping
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*/
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static unsigned char PixelToCode(unsigned char PixelValue)
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{
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switch (PixelValue)
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{
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case '0': return 0; /* standard background */
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case '1': return 1; /* standard foreground */
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case 'W': return 2; /* white */
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case 'C': return 3; /* cyan */
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case 'B': return 4; /* blue */
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case 'M': return 5; /* magenta */
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case 'R': return 6; /* red */
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case 'Y': return 7; /* yellow */
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case 'G': return 8; /* green */
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case 'K': return 9; /* black */
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case 'T': return 15; /* transparent */
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default: return 15; /* error case - return */
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}
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}
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static char BufferNextByte(statestruct *pState) {
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(pState->OutPosCur)++;
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/* Check if this position is a byte count position
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@ -144,7 +168,7 @@ static char NextCode(statestruct *pState, unsigned char * pPixelValueCur, unsign
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if ((pState->InLen) == 0)
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return AddCodeToBuffer(pState, UpNode, CodeBits);
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*pPixelValueCur = (*(pState->pIn)) - '0';
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*pPixelValueCur = PixelToCode(*(pState->pIn));
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(pState->pIn)++;
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(pState->InLen)--;
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/* Follow the string table and the data stream to the end of the longest string that has a code */
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@ -153,7 +177,7 @@ static char NextCode(statestruct *pState, unsigned char * pPixelValueCur, unsign
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if ((pState->InLen) == 0)
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return AddCodeToBuffer(pState, UpNode, CodeBits);
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*pPixelValueCur = (*(pState->pIn)) - '0';
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*pPixelValueCur = PixelToCode(*(pState->pIn));
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(pState->pIn)++;
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(pState->InLen)--;
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}
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@ -191,12 +215,12 @@ static int gif_lzw(unsigned char *pOut, int OutLength, unsigned char *pIn, int I
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if (State.InLen == 0)
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return 0;
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PixelValueCur = (unsigned char) ((*(State.pIn)) - '0');
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PixelValueCur = PixelToCode(*(State.pIn));
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(State.pIn)++;
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(State.InLen)--;
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CodeBits = 3;
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State.ClearCode = 4;
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State.FreeCode = 6;
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CodeBits = DESTINATION_IMAGE_BITS+1;
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State.ClearCode = (1 << DESTINATION_IMAGE_BITS);
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State.FreeCode = State.ClearCode+2;
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State.OutBitsFree = 8;
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State.OutPosCur = -1;
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State.fByteCountByteSet = 0;
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@ -210,7 +234,7 @@ static int gif_lzw(unsigned char *pOut, int OutLength, unsigned char *pIn, int I
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FlushStringTable(&State);
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/* Write what the GIF specification calls the "code size". */
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(State.pOut)[State.OutPosCur] = 2;
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(State.pOut)[State.OutPosCur] = DESTINATION_IMAGE_BITS;
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/* Reserve first bytecount byte */
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if (BufferNextByte(&State))
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return 0;
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@ -255,14 +279,14 @@ static int gif_lzw(unsigned char *pOut, int OutLength, unsigned char *pIn, int I
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if (AddCodeToBuffer(&State, State.ClearCode, CodeBits))
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return 0;
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CodeBits = (unsigned char) (1 + 2);
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CodeBits = (unsigned char) (1 + DESTINATION_IMAGE_BITS);
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State.FreeCode = (unsigned short) (State.ClearCode + 2);
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}
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}
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}
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INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
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char outbuf[10];
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unsigned char outbuf[10];
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FILE *gif_file;
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unsigned short usTemp;
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int byte_out;
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@ -315,6 +339,11 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
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outbuf[3] = (unsigned char) ((0xff00 & usTemp) / 0x100);
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/* write ImageBits-1 to the three least significant bits of byte 5 of
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* the Screen Descriptor
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* Bits 76543210
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* 1 : Global colour map
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* 111 : 8 bit colour depth of the palette
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* 0 : Not ordered in decreasing importance
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* 011 : 4 bit palette
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*/
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outbuf[4] = (unsigned char) (0xf0 | (0x7 & (DESTINATION_IMAGE_BITS - 1)));
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/* Background color = colortable index 0 */
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@ -322,16 +351,49 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
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/* Byte 7 must be 0x00 */
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outbuf[6] = 0x00;
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fwrite(outbuf, 7, 1, gif_file);
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/* Global Color Table (6) */
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/* RGB 0 color */
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/* Global Color Table (16*3) */
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/* Colour index 0: RGB 0 color */
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outbuf[0] = (unsigned char) (16 * ctoi(symbol->bgcolour[0])) + ctoi(symbol->bgcolour[1]);
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outbuf[1] = (unsigned char) (16 * ctoi(symbol->bgcolour[2])) + ctoi(symbol->bgcolour[3]);
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outbuf[2] = (unsigned char) (16 * ctoi(symbol->bgcolour[4])) + ctoi(symbol->bgcolour[5]);
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/* RGB 1 color */
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/* Colour index 1: RGB 1 color */
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outbuf[3] = (unsigned char) (16 * ctoi(symbol->fgcolour[0])) + ctoi(symbol->fgcolour[1]);
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outbuf[4] = (unsigned char) (16 * ctoi(symbol->fgcolour[2])) + ctoi(symbol->fgcolour[3]);
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outbuf[5] = (unsigned char) (16 * ctoi(symbol->fgcolour[4])) + ctoi(symbol->fgcolour[5]);
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fwrite(outbuf, 6, 1, gif_file);
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/* Colour index 2: "W" for White color */
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outbuf[6] = 255; outbuf[7] = 255; outbuf[8] = 255;
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fwrite(outbuf, 9, 1, gif_file);
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/* Colour index 3: "C" for Cyan colour */
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outbuf[0] = 0; outbuf[1] = 255; outbuf[2] = 255;
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/* Colour index 4: "B" for Blue colour */
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outbuf[3] = 0; outbuf[4] = 0; outbuf[5] = 255;
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/* Colour index 5: "M" for Magenta colour */
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outbuf[6] = 255; outbuf[7] = 0; outbuf[8] = 255;
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fwrite(outbuf, 9, 1, gif_file);
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/* Colour index 6: "R" for red colour */
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outbuf[0] = 255; outbuf[1] = 0; outbuf[2] = 0;
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/* Colour index 7: "Y" for yellow colour */
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outbuf[3] = 255; outbuf[4] = 255; outbuf[5] = 0;
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/* Colour index 8: "G" for green colour */
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outbuf[6] = 0; outbuf[7] = 255; outbuf[8] = 0;
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fwrite(outbuf, 9, 1, gif_file);
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/* Colour index 9: "K" for black colour */
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outbuf[0] = 0; outbuf[1] = 0; outbuf[2] = 0;
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/* Colour index 10: unused, set to black colour*/
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outbuf[3] = 0; outbuf[4] = 0; outbuf[5] = 0;
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/* Colour index 11: unused, set to black colour */
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outbuf[6] = 0; outbuf[7] = 0; outbuf[8] = 0;
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fwrite(outbuf, 9, 1, gif_file);
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/* Colour index 12: unused, set to black colour */
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outbuf[0] = 0; outbuf[1] = 0; outbuf[2] = 0;
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/* Colour index 13: unused, set to black colour*/
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outbuf[3] = 0; outbuf[4] = 0; outbuf[5] = 0;
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/* Colour index 14: unused, set to black colour */
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outbuf[6] = 0; outbuf[7] = 0; outbuf[8] = 0;
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fwrite(outbuf, 9, 1, gif_file);
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/* Colour index 15: transparent colour */
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outbuf[0] = 0; outbuf[1] = 0; outbuf[2] = 0;
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fwrite(outbuf, 3, 1, gif_file);
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/* Graphic control extension (8) */
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/* A graphic control extension block is used for overlay gifs.
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@ -380,7 +442,7 @@ INTERNAL int gif_pixel_plot(struct zint_symbol *symbol, char *pixelbuf) {
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* information on the local color table.
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* There is no local color table if its most significant bit is reset.
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*/
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outbuf[9] = (unsigned char) (0 | (0x7 & (DESTINATION_IMAGE_BITS - 1)));
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outbuf[9] = 0x00;
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fwrite(outbuf, 10, 1, gif_file);
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/* call lzw encoding */
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