libnsgif.h

Go to the documentation of this file.

/*
 * 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
 */

#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;

typedef struct gif_frame {
        bool display;
        unsigned int frame_delay;

        /* Internal members are listed below */

        unsigned int frame_pointer;
        bool virgin;
        bool opaque;
        bool redraw_required;
        unsigned char disposal_method;
        bool transparency;
        unsigned char transparency_index;
        unsigned int redraw_x;
        unsigned int redraw_y;
        unsigned int redraw_width;
        unsigned int redraw_height;
} 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);

typedef struct gif_bitmap_callback_vt {
        gif_bitmap_cb_create bitmap_create;
        gif_bitmap_cb_destroy bitmap_destroy;
        gif_bitmap_cb_get_buffer bitmap_get_buffer;

        /* Members below are optional */

        gif_bitmap_cb_set_opaque bitmap_set_opaque;
        gif_bitmap_cb_test_opaque bitmap_test_opaque;
        gif_bitmap_cb_modified bitmap_modified;
} gif_bitmap_callback_vt;

typedef struct gif_animation {
        gif_bitmap_callback_vt bitmap_callbacks;
        unsigned char *gif_data;
        unsigned int width;
        unsigned int height;
        unsigned int frame_count;
        unsigned int frame_count_partial;
        gif_frame *frames;
        int decoded_frame;
        void *frame_image;
        int loop_count;
        gif_result current_error;

        /* Internal members are listed below */

        unsigned int buffer_position;
        unsigned int buffer_size;
        unsigned int frame_holders;
        unsigned int background_index;
        unsigned int aspect_ratio;
        unsigned int colour_table_size;
        bool global_colours;
        unsigned int *global_colour_table;
        unsigned int *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