netsurf/image/gifread.h

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/*
* This file is part of NetSurf, http://netsurf.sourceforge.net/
* Licensed under the GNU General Public License,
* http://www.opensource.org/licenses/gpl-license
* Copyright 2004 Richard Wilson <not_ginger_matt@users.sourceforge.net>
*/
/** \file
* Progressive animated GIF file decoding (interface).
*/
#ifndef _NETSURF_IMAGE_GIFREAD_H_
#define _NETSURF_IMAGE_GIFREAD_H_
#include <stdbool.h>
#include "netsurf/image/bitmap.h"
/* Error return values
*/
#define GIF_INSUFFICIENT_FRAME_DATA -1
#define GIF_FRAME_DATA_ERROR -2
#define GIF_INSUFFICIENT_DATA -3
#define GIF_DATA_ERROR -4
#define GIF_INSUFFICIENT_MEMORY -5
/* Maximum colour table size
*/
#define GIF_MAX_COLOURS 256
/* Maximum LZW bits available
*/
#define GIF_MAX_LZW 12
/* The GIF frame data
*/
typedef struct gif_frame {
unsigned int frame_pointer; /**< offset (in bytes) to the GIF frame data */
unsigned int frame_delay; /**< delay (in cs) before animating the frame */
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 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;
/* The GIF animation data
*/
typedef struct gif_animation {
unsigned char *gif_data; /**< pointer to GIF data */
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 */
int decoded_frame; /**< current frame decoded to bitmap */
int loop_count; /**< number of times to loop animation */
gif_frame *frames; /**< decoded frames */
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 */
unsigned int background_colour; /**< image 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 */
int dirty_frame; /**< the current dirty frame, or -1 for none */
struct bitmap *frame_image; /**< currently decoded image */
int current_error; /**< current error type, or 0 for none*/
} gif_animation;
int gif_initialise(struct gif_animation *gif);
int gif_decode_frame(struct gif_animation *gif, unsigned int frame);
void gif_finalise(struct gif_animation *gif);
#endif