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-rw-r--r--include/libnsgif.h107
1 files changed, 107 insertions, 0 deletions
diff --git a/include/libnsgif.h b/include/libnsgif.h
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+++ b/include/libnsgif.h
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+/*
+ * 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>
+
+/* 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