/* * Copyright 2004 Richard Wilson <richard.wilson@netsurf-browser.org> * Copyright 2008 Sean Fox <dyntryx@gmail.com> * * This file is part of NetSurf's libnsgif, http://www.netsurf-browser.org/ * Licenced under the MIT License, * http://www.opensource.org/licenses/mit-license.php */ /** \file * Progressive animated GIF file decoding (interface). */ #ifndef _LIBNSGIF_H_ #define _LIBNSGIF_H_ #include <stdbool.h> #include <inttypes.h> /* Error return values */ typedef enum { GIF_WORKING = 1, GIF_OK = 0, GIF_INSUFFICIENT_FRAME_DATA = -1, GIF_FRAME_DATA_ERROR = -2, GIF_INSUFFICIENT_DATA = -3, GIF_DATA_ERROR = -4, GIF_INSUFFICIENT_MEMORY = -5, GIF_FRAME_NO_DISPLAY = -6, GIF_END_OF_FRAME = -7 } gif_result; /* The GIF frame data */ typedef struct gif_frame { bool display; /**< whether the frame should be displayed/animated */ unsigned int frame_delay; /**< delay (in cs) before animating the frame */ /** Internal members are listed below */ unsigned int frame_pointer; /**< offset (in bytes) to the GIF frame data */ bool virgin; /**< whether the frame has previously been used */ bool opaque; /**< whether the frame is totally opaque */ bool redraw_required; /**< whether a forcable screen redraw is required */ unsigned char disposal_method; /**< how the previous frame should be disposed; affects plotting */ bool transparency; /**< whether we acknoledge transparency */ unsigned char transparency_index; /**< the index designating a transparent pixel */ unsigned int redraw_x; /**< x co-ordinate of redraw rectangle */ unsigned int redraw_y; /**< y co-ordinate of redraw rectangle */ unsigned int redraw_width; /**< width of redraw rectangle */ unsigned int redraw_height; /**< height of redraw rectangle */ } gif_frame; /* API for Bitmap callbacks */ typedef void* (*gif_bitmap_cb_create)(int width, int height); typedef void (*gif_bitmap_cb_destroy)(void *bitmap); typedef unsigned char* (*gif_bitmap_cb_get_buffer)(void *bitmap); typedef void (*gif_bitmap_cb_set_opaque)(void *bitmap, bool opaque); typedef bool (*gif_bitmap_cb_test_opaque)(void *bitmap); typedef void (*gif_bitmap_cb_modified)(void *bitmap); /* The Bitmap callbacks function table */ typedef struct gif_bitmap_callback_vt { gif_bitmap_cb_create bitmap_create; /**< Create a bitmap. */ gif_bitmap_cb_destroy bitmap_destroy; /**< Free a bitmap. */ gif_bitmap_cb_get_buffer bitmap_get_buffer; /**< Return a pointer to the pixel data in a bitmap. */ /** Members below are optional */ gif_bitmap_cb_set_opaque bitmap_set_opaque; /**< Sets whether a bitmap should be plotted opaque. */ gif_bitmap_cb_test_opaque bitmap_test_opaque; /**< Tests whether a bitmap has an opaque alpha channel. */ gif_bitmap_cb_modified bitmap_modified; /**< The bitmap image has changed, so flush any persistant cache. */ } gif_bitmap_callback_vt; /* The GIF animation data */ typedef struct gif_animation { gif_bitmap_callback_vt bitmap_callbacks; /**< callbacks for bitmap functions */ unsigned char *gif_data; /**< pointer to GIF data */ unsigned int width; /**< width of GIF (may increase during decoding) */ unsigned int height; /**< heigth of GIF (may increase during decoding) */ unsigned int frame_count; /**< number of frames decoded */ unsigned int frame_count_partial; /**< number of frames partially decoded */ gif_frame *frames; /**< decoded frames */ int decoded_frame; /**< current frame decoded to bitmap */ void *frame_image; /**< currently decoded image; stored as bitmap from bitmap_create callback */ int loop_count; /**< number of times to loop animation */ gif_result current_error; /**< current error type, or 0 for none*/ /** Internal members are listed below */ unsigned int buffer_position; /**< current index into GIF data */ unsigned int buffer_size; /**< total number of bytes of GIF data available */ unsigned int frame_holders; /**< current number of frame holders */ unsigned int background_index; /**< index in the colour table for the background colour */ unsigned int aspect_ratio; /**< image aspect ratio (ignored) */ unsigned int colour_table_size; /**< size of colour table (in entries) */ bool global_colours; /**< whether the GIF has a global colour table */ unsigned int *global_colour_table; /**< global colour table */ unsigned int *local_colour_table; /**< local colour table */ } gif_animation; void gif_create(gif_animation *gif, gif_bitmap_callback_vt *bitmap_callbacks); gif_result gif_initialise(gif_animation *gif, size_t size, unsigned char *data); gif_result gif_decode_frame(gif_animation *gif, unsigned int frame); void gif_finalise(gif_animation *gif); #endif