From ad07b6e656f36d41028e68c0e0f99eb34bfb8fc8 Mon Sep 17 00:00:00 2001
From: Richard Wilson <rjw@netsurf-browser.org>
Date: Sat, 3 Apr 2004 11:49:48 +0000
Subject: [PATCH] [project @ 2004-04-03 11:49:48 by rjw] GIF file reading

svn path=/import/netsurf/; revision=710
---
 riscos/gifread.h | 81 ++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 81 insertions(+)
 create mode 100644 riscos/gifread.h

diff --git a/riscos/gifread.h b/riscos/gifread.h
new file mode 100644
index 000000000..5cefede29
--- /dev/null
+++ b/riscos/gifread.h
@@ -0,0 +1,81 @@
+/*
+ * 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@sourceforge.net>
+ */
+
+#ifndef _NETSURF_RISCOS_GIFREAD_H_
+#define _NETSURF_RISCOS_GIFREAD_H_
+
+#include "oslib/osspriteop.h"
+
+/*	Error return values
+*/
+#define GIF_INSUFFICIENT_DATA -1
+#define GIF_DATA_ERROR -2
+#define GIF_INSUFFICIENT_MEMORY -3
+#define GIF_INSUFFICIENT_FRAME_DATA -4
+#define GIF_FRAME_DATA_ERROR -5
+
+/*	Colour map size constant. Because we don't want to allocate
+	memory each time we decode a frame we get enough so all frames
+	will fit in there.
+*/
+#define GIF_MAX_COLOURS 256
+
+/*	Maximum LZW bits available
+*/
+#define GIF_MAX_LZW 12
+
+/*	A simple hold-all for our GIF data
+*/
+struct gif_animation {
+	/*	Encoded GIF data
+	*/
+	unsigned char *gif_data;
+	unsigned int buffer_position;
+	unsigned int buffer_size;
+	
+	/*	Progressive decoding data
+	*/
+	unsigned int global_colours;
+	unsigned int frame_holders;
+	unsigned int colour_table_size;
+	unsigned int *frame_pointers;
+
+	/*	Animation data
+	*/
+	unsigned int current_frame;
+	unsigned int decoded_frame;
+	unsigned int loop_count;
+	unsigned int *frame_delays;
+
+	/*	Decoded GIF data
+	*/
+	unsigned int width;
+	unsigned int height;
+	unsigned int frame_count;
+	unsigned int frame_count_partial;
+	unsigned int background_colour;
+	unsigned int aspect_ratio;
+	unsigned int *global_colour_table;
+	unsigned int *local_colour_table;
+
+	/*	Decoded frame data
+	*/
+	unsigned int frame_offset_x;
+	unsigned int frame_offset_y;
+	unsigned int frame_width;
+	unsigned int frame_height;
+	unsigned int background_action;
+	osspriteop_header *frame_image;
+};
+
+/*	Function declarations
+*/
+int gif_initialise(struct gif_animation *gif);
+int gif_decode_frame(struct gif_animation *gif, int frame);
+void gif_finalise(struct gif_animation *gif);
+
+#endif