From 15e01152da335f5a9e7617674ffa54cb1bdef957 Mon Sep 17 00:00:00 2001
From: Ray Strode <rstrode@redhat.com>
Date: Fri, 14 Jun 2013 16:11:30 -0400
Subject: [PATCH] background: downscale background to fit in texture limits

Some cards have 2k texture limits, which can be smaller than
commonly sized backgrounds.

This commit downscales the background in this situation, so that
it won't fail to load.

https://bugzilla.gnome.org/show_bug.cgi?id=702283
---
 src/compositor/meta-background.c | 30 ++++++++++++++++++++++++++++++
 1 file changed, 30 insertions(+)

diff --git a/src/compositor/meta-background.c b/src/compositor/meta-background.c
index fca5dce60..35ca45c53 100644
--- a/src/compositor/meta-background.c
+++ b/src/compositor/meta-background.c
@@ -32,6 +32,8 @@
 
 #include <clutter/clutter.h>
 
+#include <GL/gl.h>
+
 #include "cogl-utils.h"
 #include "compositor-private.h"
 #include "mutter-enum-types.h"
@@ -971,6 +973,7 @@ load_file (GTask            *task,
 {
   GError *error = NULL;
   GdkPixbuf *pixbuf;
+  int max_texture_size = 0;
 
   pixbuf = gdk_pixbuf_new_from_file (task_data->filename,
                                      &error);
@@ -981,6 +984,33 @@ load_file (GTask            *task,
       return;
     }
 
+  glGetIntegerv (GL_MAX_TEXTURE_SIZE, &max_texture_size);
+
+  if (glGetError () != GL_NO_ERROR)
+      max_texture_size = 0;
+
+  if (max_texture_size > 0) {
+      double width, height;
+
+      width = gdk_pixbuf_get_width (pixbuf);
+      height = gdk_pixbuf_get_height (pixbuf);
+
+      if (width > max_texture_size || height > max_texture_size) {
+          GdkPixbuf *scaled_pixbuf;
+
+          if (width > height) {
+              width = max_texture_size;
+              height *= max_texture_size / width;
+          } else {
+              width *= max_texture_size / height;
+              height = max_texture_size;
+          }
+          scaled_pixbuf = gdk_pixbuf_scale_simple (pixbuf, width, height, GDK_INTERP_BILINEAR);
+          g_object_unref (pixbuf);
+          pixbuf = scaled_pixbuf;
+      }
+  }
+
   g_task_return_pointer (task, pixbuf, (GDestroyNotify) g_object_unref);
 }