spynccat/gif2bmp

FUNCTION:GIF2BMP SOURCE CODE:g2b_1.c LIBRARY USE:GIFLIB RUNNING:g2b_1

/////////////////////////////////////////////////////////////////////////////////////////////// 0.api:int g2b(char *gif,char *bmp,char *record) input parameter: gif:gif file name.eg:*gif="test.gif" bmp:output bmp file name.eg:if want to output as[testbmp1.bmp,testbmp2.bmp,testbmp3.bmp......],set *bmp="testbmp" record:record file name.eg:*record="record.txt"

return value:

return pass/error code,refer to No.9 ERROR_CODE

///////////////////////////////////////////////////////////////////////////////////////////////

1.function:decode gif image(test.gif),get graphic and extension block info and output. 2.input:test.gif(url:test.gif) 3.output: 3.1.pics:1.bmp,2.bmp....n.bmp(url:n.bmp) 3.2.extension:record.txt 4.routine: while(block is not a teminate block) do if(block is a graphic block) do block => n.bmp(n:num of pics meet now) "<n(left_space,upper_space)[length,height]>" => record.txt end if(block is a extension block) do if(block is not a graphicm extension block) (do not deal it)continue; "<disposal_method,user_input_flag,transparent_color_flag,delay_time(10ns),transparent_color_index>" => record.txt end end

5.disposal_method: 0:do not use 1:remove now image 2:return to backgroundcolor 3:return to last status

6.flags: user_input_flag:1/0-need/not need a user input to continue transparent_color_flag:1/0-use/not use transparent color

7.functions:(if not in list,means it is a function from GIFLIB Library) FILE* write_bmp_header(FILE *fpout) : write bmp header,should used after Gif_read() void GIF_EXIT(char info) : exit with printing info,instead EXIT_FAILURE void Gif_info_print(char fname) : print GIF(filename:fname) info,include Screen_width/height,ColorResolution,BackgroundColor,number of the Image dealing now void Gif_read() : read GIF with name(GifName),open a new Gif File(GifFile) char itoa(int value, char result, int base) : normal itoa,incase <stdlib.h> do not support itoa() void DumpScreen2RGBA (char *foutName, GifRowType *ScreenBuffer, ColorMapObject *ColorMap, int ScreenWidth, : dump data in screenbuffer(ScreenBuffer) to bmpfile(foutName),using colormap(ColorMap),size of screen int ScreenHeight) (ScreenWidth,ScreenHeight).must be used after Gif_decode_imgdesc()

void Gif_decode_main() : decord gifblock until meet teminate block,should used after GIF_read(),using Gif_decode_imgdesc(),Gif_decode_extension() void Gif_decode_imgdesc() : decord image block,get block data to buffer,use DumpScreen2RGBA() to generate bmp void Gif_decode_extension() : decord graphic extension block,get block data to record.txt

8.static vars: GifFileType *GifFile; :Gif File opened,used in GIFLIB GifRowType *ScreenBuffer; :Gif buffer,used in DumpScreen2RGB(),save image data char GifName[MAX_FILENAME_LENGTH]; :gif file name char OutFileName[MAX_FILENAME_LENGTH]; :output bmp file name char RecordOutName[MAX_FILENAME_LENGTH]; :record file name int *Error; :Error,used in GIFLIB int piclist; :number of now picture int InterlacedOffset[4]={0,4,2,1}; :used for decord gif,see gif introduction for more int InterlacedJumps[4]={8,8,4,2}; :used for decord gif,see gif introduction for more GifByteType *extension; :pointer of extension block FILE *RecordOutFile; :pointer for File record

9.Error code enum ERROR_CODE{PASS,PASS_NORECORD,ERROR_GIFREAD,ERROR_BMPWRITE,ERROR_IMGDESC,ERROR_EXTDESC,ERROR_COLORMAP,ERROR_IMGOUTLINE,ERROR_RECORDTYPE,ERROR_MEMORY,ERROR_GETLINE}; PASS: pass,no error or warning occured PASS_NORECORD: pass,cannot open record file,meaning cannot save extension block data ERROR_GIFREAD: error,cannot open or read GIF file ERROR_BMPWRITE: error,cannot open or write BMP file ERROR_IMGDESC: error,cannot read image desc block with GIFLIB ERROR_EXTDESC: error,cannot read extension block with GIFLIB ERROR_COLORMAP: error,cannot read colormap with GIFLIB ERROR_IMGOUTLINE: error,image is out of border,gif file may be damaged ERROR_RECORDTYPE: error,unexpected record type occurred,gif file may be damaged ERROR_MEMORY: error,no enough memory ERROR_GETLINE: error,cannot get image data with GFIFLIB