From 54f903d1b457a280f2cf0a677667428dd3dee239 Mon Sep 17 00:00:00 2001
From: Richard Wilson <rjw@netsurf-browser.org>
Date: Sun, 23 Jan 2005 15:20:45 +0000
Subject: [project @ 2005-01-23 15:20:45 by rjw] Fix for first frame of a GIF
 animation not always being correctly cleared

svn path=/import/netsurf/; revision=1462
---
 image/gif.c     | 16 +++++++++++-----
 image/gifread.c | 22 +++++++---------------
 2 files changed, 18 insertions(+), 20 deletions(-)

(limited to 'image')

diff --git a/image/gif.c b/image/gif.c
index be59c478c..617723bf3 100644
--- a/image/gif.c
+++ b/image/gif.c
@@ -216,11 +216,17 @@ void nsgif_animate(void *p)
 				c->data.gif.gif->frames[c->data.gif.current_frame - 1].redraw_required;
 	} else {
 		/* do advanced check */
-		data.redraw.full_redraw = !((c->data.gif.current_frame == 0) &&
-				(bitmap_get_opaque(c->data.gif.gif->frame_image)) &&
-				(data.redraw.x == 0) && (data.redraw.y == 0) &&
-				(data.redraw.width = c->data.gif.gif->width) &&
-				(data.redraw.height = c->data.gif.gif->height));
+		if ((data.redraw.x == 0) && (data.redraw.y == 0) &&
+				(data.redraw.width == c->data.gif.gif->width) &&
+				(data.redraw.height == c->data.gif.gif->height)) {
+			data.redraw.full_redraw = bitmap_get_opaque(c->data.gif.gif->frame_image);
+		} else {	
+			data.redraw.full_redraw = true;
+			data.redraw.x = 0;
+			data.redraw.y = 0;
+			data.redraw.width = c->data.gif.gif->width;
+			data.redraw.height = c->data.gif.gif->height;
+		}
 	}
 
 	/* other data */
diff --git a/image/gifread.c b/image/gifread.c
index 8ca84d952..a7d07e319 100644
--- a/image/gifread.c
+++ b/image/gifread.c
@@ -247,13 +247,6 @@ int gif_initialise(struct gif_animation *gif) {
 	/*	Update the redraw areas now we know the full data set
 	*/
 	if (gif->frame_count_partial > 0) {
-		/*	Set the redraw for the first frame to the maximum frame size
-		*/
-		gif->frames[0].redraw_x = 0;
-		gif->frames[0].redraw_y = 0;
-		gif->frames[0].redraw_width = gif->width;
-		gif->frames[0].redraw_height = gif->height;
-
 		/*	We now work backwards to update the redraw characteristics of frames
 			with clear codes to stop a snowball effect of the redraw areas. It doesn't
 			really make much difference for most images, and will not work as well
@@ -261,7 +254,7 @@ int gif_initialise(struct gif_animation *gif) {
 			for multiple calls to this routine when decoding progressively.
 		*/
 		for (frame = gif->frame_count_partial - 1; frame > 0; frame--) {
-		  	if (gif->frames[frame].redraw_required) {
+		  	if (gif->frames[frame - 1].redraw_required) {
 				if (gif->frames[frame].redraw_x > gif->frames[frame - 1].redraw_x) {
 					gif->frames[frame].redraw_width +=
 							(gif->frames[frame].redraw_x - gif->frames[frame - 1].redraw_x);
@@ -408,8 +401,8 @@ int gif_initialise_frame(struct gif_animation *gif) {
 	*/
 	gif->frames[frame].frame_pointer = gif->buffer_position;
 	gif->frames[frame].virgin = true;
-	gif->frames[frame].frame_delay = 100;	// Paranoia
-	gif->frames[frame].redraw_required = 0;	// Paranoia
+	gif->frames[frame].frame_delay = 100;
+	gif->frames[frame].redraw_required = false;
 
 	/*	Invalidate any previous decoding we have of this frame
 	*/
@@ -509,9 +502,7 @@ int gif_initialise_frame(struct gif_animation *gif) {
 		/*	if we are clearing the background then we need to redraw enough to cover the previous
 			frame too
 		*/
-		if ((background_action == 2) || (background_action == 3)) {
-			gif->frames[frame].redraw_required = 1;
-		}
+		gif->frames[frame].redraw_required = ((background_action == 2) || (background_action == 3));
 
 		/*	Boundary checking - shouldn't ever happen except with junk data
 		*/
@@ -611,6 +602,8 @@ int gif_decode_frame(struct gif_animation *gif, unsigned int frame) {
 	/*	If the previous frame was dirty, remove it
 	*/
 	if (!clear_image) {
+	  	if (frame == 0)
+	  		gif->dirty_frame = -1;
 		if (gif->decoded_frame == gif->dirty_frame) {
 			clear_image = true;
 			if (frame != 0) gif_decode_frame(gif, gif->dirty_frame);
@@ -635,9 +628,8 @@ 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 == -1)) {
+		if ((frame == 0) || (gif->decoded_frame == -1))
 			memset((char*)frame_data, 0x00, gif->width * gif->height * sizeof(int));
-		}
 		gif->decoded_frame = frame;
 	}
 
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