From: Colin Clark <colin.clark@cclark.uk>
Date: Sun, 22 Aug 2021 13:31:03 +0000 (+0100)
Subject: Fix #813: Animated GIF should use faster antialiasing (or none at all)
X-Git-Tag: v1.7~71
X-Git-Url: http://geeqie.org/cgi-bin/gitweb.cgi?p=geeqie.git;a=commitdiff_plain;h=451e12690e443bd74a5ce9a597f344e14ef40089

Fix #813: Animated GIF should use faster antialiasing (or none at all)

https://github.com/BestImageViewer/geeqie/issues/813

If the file extension is .gif, 2pass is set to FALSE, and interpolation
is set to nearest.
---

diff --git a/src/image.c b/src/image.c
index c81b1c50..889f241e 100644
--- a/src/image.c
+++ b/src/image.c
@@ -1095,6 +1095,15 @@ static void image_change_complete(ImageWindow *imd, gdouble zoom)
 			pr = PIXBUF_RENDERER(imd->pr);
 			pr->zoom = zoom;	/* store the zoom, needed by the loader */
 
+			/* Disable 2-pass for GIFs. Animated GIFs can flicker when enabled
+			 * Reduce quality to worst but fastest to avoid dropped frames */
+			if (g_ascii_strcasecmp(imd->image_fd->extension, ".GIF") == 0)
+				{
+				g_object_set(G_OBJECT(imd->pr), "zoom_2pass", FALSE, NULL);
+				g_object_set(G_OBJECT(imd->pr), "zoom_quality", GDK_INTERP_NEAREST, NULL);
+				}
+
+
 			if (image_load_begin(imd, imd->image_fd))
 				{
 				imd->unknown = FALSE;