[project @ 2004-11-09 21:27:59 by rjw]

Fix for GIF dirty frame clearance bug.

svn path=/import/netsurf/; revision=1353

2 files changed, 10 insertions, 9 deletions

diff --git a/image/gifread.c b/image/gifread.c
index 5fbfe83d4..77980ce25 100644
--- a/image/gifread.c
+++ b/image/gifread.c
@@ -134,7 +134,7 @@ int gif_initialise(struct gif_animation *gif) {
 		*/
 		gif->frame_count = 0;
 		gif->frame_count_partial = 0;
-		gif->decoded_frame = 0xffffffff;
+		gif->decoded_frame = -1;
 
 		/*	Check we are a GIF
 		*/
@@ -339,7 +339,7 @@ static int gif_initialise_sprite(struct gif_animation *gif, unsigned int width,
 
 	/*	Invalidate our currently decoded image
 	*/
-	gif->decoded_frame = 0xffffffff;
+	gif->decoded_frame = -1;
 	return 0;
 }
 
@@ -354,7 +354,7 @@ static int gif_initialise_sprite(struct gif_animation *gif, unsigned int width,
 		1 for success (GIF terminator found)
 */
 int gif_initialise_frame(struct gif_animation *gif) {
-	unsigned int frame;
+	int frame;
 	gif_frame *temp_buf;
 
 	unsigned char *gif_data, *gif_end;
@@ -389,7 +389,7 @@ int gif_initialise_frame(struct gif_animation *gif) {
 
 	/*	Get some memory to store our pointers in etc.
 	*/
-	if (gif->frame_holders <= frame) {
+	if ((int)gif->frame_holders <= frame) {
 		/*	Allocate more memory
 		*/
 		if ((temp_buf = (gif_frame *)realloc(gif->frames,
@@ -413,7 +413,7 @@ int gif_initialise_frame(struct gif_animation *gif) {
 
 	/*	Invalidate any previous decoding we have of this frame
 	*/
-	if (gif->decoded_frame == frame) gif->decoded_frame = 0xffffffff;
+	if (gif->decoded_frame == frame) gif->decoded_frame = -1;
 
 	/*	We pretend to initialise the frames, but really we just skip over all
 		the data contained within. This is all basically a cut down version of
@@ -606,7 +606,7 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
 	/*	Ensure we have a frame to decode
 	*/
 	if (frame > gif->frame_count_partial) return GIF_INSUFFICIENT_DATA;
-	if ((!clear_image) && (frame == gif->decoded_frame)) return 0;
+	if ((!clear_image) && ((int)frame == gif->decoded_frame)) return 0;
 
 	/*	If the previous frame was dirty, remove it
 	*/
@@ -635,7 +635,7 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
 	*/
 	frame_data = (unsigned int *)bitmap_get_buffer(gif->frame_image);
 	if (!clear_image) {
-		if ((frame == 0) || (gif->decoded_frame == 0xffffffff)) {
+		if ((frame == 0) || (gif->decoded_frame == -1)) {
 			memset((char*)frame_data, 0x00, gif->width * gif->height * sizeof(int));
 		}
 		gif->decoded_frame = frame;
@@ -758,6 +758,7 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
 			*/
 			if ((background_action == 2) || (background_action == 3)) {
 				gif->dirty_frame = frame;
+				LOG(("Dirty frame %i", gif->dirty_frame));
 			}
 
 			/*	Initialise the LZW decoding
diff --git a/image/gifread.h b/image/gifread.h
index 77e899b81..f5d88d481 100644
--- a/image/gifread.h
+++ b/image/gifread.h
@@ -51,7 +51,7 @@ typedef struct gif_animation {
 	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 decoded_frame;		/**< current frame decoded to bitmap */
+	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) */
@@ -64,7 +64,7 @@ typedef struct gif_animation {
 	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 */
-	unsigned int dirty_frame;		/**< the current dirty frame, or -1 for none */
+	int dirty_frame;			/**< the current dirty frame, or -1 for none */
 	struct bitmap *frame_image;		/**< currently decoded image */
 } gif_animation;