ximagif.h
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上传日期:2021-07-05
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- /*
- * File: ximagif.h
- * Purpose: GIF Image Class Loader and Writer
- */
- /* ==========================================================
- * CxImageGIF (c) 07/Aug/2001 Davide Pizzolato - www.xdp.it
- * For conditions of distribution and use, see copyright notice in ximage.h
- *
- * Special thanks to Troels Knakkergaard for new features, enhancements and bugfixes
- *
- * original CImageGIF and CImageIterator implementation are:
- * Copyright: (c) 1995, Alejandro Aguilar Sierra <asierra(at)servidor(dot)unam(dot)mx>
- *
- * 6/15/97 Randy Spann: Added GIF87a writing support
- * R.Spann@ConnRiver.net
- *
- * DECODE.C - An LZW decoder for GIF
- * Copyright (C) 1987, by Steven A. Bennett
- * Copyright (C) 1994, C++ version by Alejandro Aguilar Sierra
- *
- * In accordance with the above, I want to credit Steve Wilhite who wrote
- * the code which this is heavily inspired by...
- *
- * GIF and 'Graphics Interchange Format' are trademarks (tm) of
- * Compuserve, Incorporated, an H&R Block Company.
- *
- * Release Notes: This file contains a decoder routine for GIF images
- * which is similar, structurally, to the original routine by Steve Wilhite.
- * It is, however, somewhat noticably faster in most cases.
- *
- * ==========================================================
- */
- #if !defined(__ximaGIF_h)
- #define __ximaGIF_h
- #include "ximage.h"
- #if CXIMAGE_SUPPORT_GIF
- typedef short int code_int;
- /* Various error codes used by decoder */
- #define OUT_OF_MEMORY -10
- #define BAD_CODE_SIZE -20
- #define READ_ERROR -1
- #define WRITE_ERROR -2
- #define OPEN_ERROR -3
- #define CREATE_ERROR -4
- #define MAX_CODES 4095
- #define GIFBUFTAM 16383
- #define TRANSPARENCY_CODE 0xF9
- //LZW GIF Image compression
- #define MAXBITSCODES 12
- #define HSIZE 5003 /* 80% occupancy */
- #define MAXCODE(n_bits) (((code_int) 1 << (n_bits)) - 1)
- #define HashTabOf(i) htab[i]
- #define CodeTabOf(i) codetab[i]
- class CImageIterator;
- class DLL_EXP CxImageGIF: public CxImage
- {
- #pragma pack(1)
- typedef struct tag_gifgce{
- BYTE flags; /*res:3|dispmeth:3|userinputflag:1|transpcolflag:1*/
- WORD delaytime;
- BYTE transpcolindex;
- } struct_gifgce;
- typedef struct tag_dscgif{ /* Logic Screen Descriptor */
- char header[6]; /* Firma and version */
- WORD scrwidth;
- WORD scrheight;
- char pflds;
- char bcindx;
- char pxasrat;
- } struct_dscgif;
- typedef struct tag_image{ /* Image Descriptor */
- WORD l;
- WORD t;
- WORD w;
- WORD h;
- BYTE pf;
- } struct_image;
- typedef struct tag_TabCol{ /* Tabla de colores */
- short colres; /* color resolution */
- short sogct; /* size of global color table */
- rgb_color paleta[256]; /* paleta */
- } struct_TabCol;
- typedef struct tag_RLE{
- int rl_pixel;
- int rl_basecode;
- int rl_count;
- int rl_table_pixel;
- int rl_table_max;
- int just_cleared;
- int out_bits;
- int out_bits_init;
- int out_count;
- int out_bump;
- int out_bump_init;
- int out_clear;
- int out_clear_init;
- int max_ocodes;
- int code_clear;
- int code_eof;
- unsigned int obuf;
- int obits;
- unsigned char oblock[256];
- int oblen;
- } struct_RLE;
- #pragma pack()
- public:
- CxImageGIF(): CxImage(CXIMAGE_FORMAT_GIF) {m_loops=0; info.dispmeth=0; m_comment[0]=' ';}
- // bool Load(const TCHAR * imageFileName){ return CxImage::Load(imageFileName,CXIMAGE_FORMAT_GIF);}
- // bool Save(const TCHAR * imageFileName){ return CxImage::Save(imageFileName,CXIMAGE_FORMAT_GIF);}
-
- bool Decode(CxFile * fp);
- bool Decode(FILE *fp) { CxIOFile file(fp); return Decode(&file); }
- #if CXIMAGE_SUPPORT_ENCODE
- bool Encode(CxFile * fp);
- bool Encode(CxFile * fp, CxImage ** pImages, int pagecount, bool bLocalColorMap = false, bool bLocalDispMeth = false);
- bool Encode(FILE *fp) { CxIOFile file(fp); return Encode(&file); }
- bool Encode(FILE *fp, CxImage ** pImages, int pagecount, bool bLocalColorMap = false)
- { CxIOFile file(fp); return Encode(&file, pImages, pagecount, bLocalColorMap); }
- #endif // CXIMAGE_SUPPORT_ENCODE
- void SetLoops(int loops);
- long GetLoops();
- void SetComment(const char* sz_comment_in);
- void GetComment(char* sz_comment_out);
- protected:
- bool DecodeExtension(CxFile *fp);
- void EncodeHeader(CxFile *fp);
- void EncodeLoopExtension(CxFile *fp);
- void EncodeExtension(CxFile *fp);
- void EncodeBody(CxFile *fp, bool bLocalColorMap = false);
- void EncodeComment(CxFile *fp);
- bool EncodeRGB(CxFile *fp);
- void GifMix(CxImage & imgsrc2, struct_image & imgdesc);
-
- struct_gifgce gifgce;
- int curx, cury;
- long CountDown;
- unsigned long cur_accum;
- int cur_bits;
- int interlaced, iypos, istep, iheight, ipass;
- int ibf;
- int ibfmax;
- BYTE buf[GIFBUFTAM + 1];
- // Implementation
- int GifNextPixel ();
- void Putword (int w, CxFile* fp );
- void compressNONE (int init_bits, CxFile* outfile);
- void compressLZW (int init_bits, CxFile* outfile);
- void output (code_int code );
- void cl_hash (long hsize);
- void char_out (int c);
- void flush_char ();
- short init_exp(short size);
- short get_next_code(CxFile*);
- short decoder(CxFile*, CImageIterator* iter, short linewidth, int &bad_code_count);
- int get_byte(CxFile*);
- int out_line(CImageIterator* iter, unsigned char *pixels, int linelen);
- int get_num_frames(CxFile *f,struct_TabCol* TabColSrc,struct_dscgif* dscgif);
- long seek_next_image(CxFile* fp, long position);
- short curr_size; /* The current code size */
- short clear; /* Value for a clear code */
- short ending; /* Value for a ending code */
- short newcodes; /* First available code */
- short top_slot; /* Highest code for current size */
- short slot; /* Last read code */
- /* The following static variables are used
- * for seperating out codes */
- short navail_bytes; /* # bytes left in block */
- short nbits_left; /* # bits left in current BYTE */
- BYTE b1; /* Current BYTE */
- BYTE byte_buff[257]; /* Current block */
- BYTE *pbytes; /* Pointer to next BYTE in block */
- /* The reason we have these seperated like this instead of using
- * a structure like the original Wilhite code did, is because this
- * stuff generally produces significantly faster code when compiled...
- * This code is full of similar speedups... (For a good book on writing
- * C for speed or for space optomisation, see Efficient C by Tom Plum,
- * published by Plum-Hall Associates...)
- */
- BYTE stack[MAX_CODES + 1]; /* Stack for storing pixels */
- BYTE suffix[MAX_CODES + 1]; /* Suffix table */
- WORD prefix[MAX_CODES + 1]; /* Prefix linked list */
- //LZW GIF Image compression routines
- long htab [HSIZE];
- unsigned short codetab [HSIZE];
- int n_bits; /* number of bits/code */
- code_int maxcode; /* maximum code, given n_bits */
- code_int free_ent; /* first unused entry */
- int clear_flg;
- int g_init_bits;
- CxFile* g_outfile;
- int ClearCode;
- int EOFCode;
- int a_count;
- char accum[256];
- char m_comment[256];
- int m_loops;
- //RLE compression routines
- void compressRLE( int init_bits, CxFile* outfile);
- void rle_clear(struct_RLE* rle);
- void rle_flush(struct_RLE* rle);
- void rle_flush_withtable(int count, struct_RLE* rle);
- void rle_flush_clearorrep(int count, struct_RLE* rle);
- void rle_flush_fromclear(int count,struct_RLE* rle);
- void rle_output_plain(int c,struct_RLE* rle);
- void rle_reset_out_clear(struct_RLE* rle);
- unsigned int rle_compute_triangle_count(unsigned int count, unsigned int nrepcodes);
- unsigned int rle_isqrt(unsigned int x);
- void rle_write_block(struct_RLE* rle);
- void rle_block_out(unsigned char c, struct_RLE* rle);
- void rle_block_flush(struct_RLE* rle);
- void rle_output(int val, struct_RLE* rle);
- void rle_output_flush(struct_RLE* rle);
- };
- #endif
- #endif