#ifndef CGIF_H #define CGIF_H #include #include #ifdef __cplusplus extern "C" { #endif // flags to set the GIF/frame-attributes #define CGIF_ATTR_IS_ANIMATED (1uL << 1) // make an animated GIF (default is non-animated GIF) #define CGIF_ATTR_NO_GLOBAL_TABLE (1uL << 2) // disable global color table (global color table is default) #define CGIF_ATTR_HAS_TRANSPARENCY (1uL << 3) // first entry in color table contains transparency #define CGIF_FRAME_ATTR_USE_LOCAL_TABLE (1uL << 0) // use a local color table for a frame (local color table is not used by default) // flags to decrease GIF-size #define CGIF_FRAME_GEN_USE_TRANSPARENCY (1uL << 0) // use transparency optimization (setting pixels identical to previous frame transparent) #define CGIF_FRAME_GEN_USE_DIFF_WINDOW (1uL << 1) // do encoding just for the sub-window that has changed from previous frame #define CGIF_INFINITE_LOOP (0x0000uL) // for animated GIF: 0 specifies infinite loop typedef enum { CGIF_ERROR = -1, // something unspecified failed CGIF_OK = 0, // everything OK CGIF_EWRITE, // writing GIF data failed CGIF_EALLOC, // allocating memory failed CGIF_ECLOSE, // final call to fclose failed CGIF_EOPEN, // failed to open output file CGIF_EINDEX, // invalid index in image data provided by user // internal section (values subject to change) CGIF_PENDING, } cgif_result; typedef struct st_gif CGIF; // struct for the full GIF typedef struct st_frame CGIF_Frame; // struct for a single frame typedef struct st_gifconfig CGIF_Config; // global cofinguration parameters of the GIF typedef struct st_frameconfig CGIF_FrameConfig; // local configuration parameters for a frame typedef int cgif_write_fn(void* pContext, const uint8_t* pData, const size_t numBytes); // callback function for stream-based output // prototypes CGIF* cgif_newgif (CGIF_Config* pConfig); // creates a new GIF (returns pointer to new GIF or NULL on error) int cgif_addframe (CGIF* pGIF, CGIF_FrameConfig* pConfig); // adds the next frame to an existing GIF (returns 0 on success) int cgif_close (CGIF* pGIF); // close file and free allocated memory (returns 0 on success) // CGIF_Config type (parameters passed by user) // note: must stay AS IS for backward compatibility struct st_gifconfig { uint8_t* pGlobalPalette; // global color table of the GIF const char* path; // path of the GIF to be created, mutually exclusive with pWriteFn uint32_t attrFlags; // fixed attributes of the GIF (e.g. whether it is animated or not) uint32_t genFlags; // flags that determine how the GIF is generated (e.g. optimization) uint16_t width; // width of each frame in the GIF uint16_t height; // height of each frame in the GIF uint16_t numGlobalPaletteEntries; // size of the global color table uint16_t numLoops; // number of repetitons of an animated GIF (set to INFINITE_LOOP for infinite loop) cgif_write_fn *pWriteFn; // callback function for chunks of output data, mutually exclusive with path void* pContext; // opaque pointer passed as the first parameter to pWriteFn }; // CGIF_FrameConfig type (parameters passed by user) // note: must stay AS IS for backward compatibility struct st_frameconfig { uint8_t* pLocalPalette; // local color table of a frame uint8_t* pImageData; // image data to be encoded uint32_t attrFlags; // fixed attributes of the GIF frame uint32_t genFlags; // flags that determine how the GIF frame is created (e.g. optimization) uint16_t delay; // delay before the next frame is shown (units of 0.01 s) uint16_t numLocalPaletteEntries; // size of the local color table }; // CGIF_Frame type // note: internal sections, subject to change in future versions struct st_frame { CGIF_FrameConfig config; // (internal) configutation parameters of the frame (see above) struct st_frame* pBef; // (internal) pointer to frame before (needed e.g. for transparency optimization) struct st_frame* pNext; // (internal) pointer to next frame uint8_t* pRasterData; // (internal) pointer to LZW-data uint32_t sizeRasterData; // (internal) size of the LZW-data uint16_t initDictLen; // (internal) length of the initial color dictionary (maximum 256) uint16_t width; // actual width of frame uint16_t height; // actual height of frame uint16_t top; // actual top offset of frame uint16_t left; // actual left offset of frame uint8_t transIndex; // (internal) index indicating transparent pixel uint8_t aGraphicExt[8]; // uint8_t aImageHeader[10]; // (internal) header of the frame uint8_t aLocalColorTable[256 * 3]; // uint8_t initCodeLen; // initial length of the LZW-codes in bits (minimum 3, maximum 12) }; // CGIF type // note: internal sections, subject to change in future versions struct st_gif { CGIF_Config config; // (internal) configutation parameters of the GIF (see above) FILE* pFile; uint8_t aHeader[13]; // (internal) header of the GIF uint8_t aGlobalColorTable[256 * 3]; // (internal) global color table uint8_t aAppExt[19]; // CGIF_Frame* pCurFrame; // (internal) pointer to current frame CGIF_Frame firstFrame; // (internal) pointer to next frame cgif_result curResult; }; #ifdef __cplusplus } #endif #endif // CGIF_H