gdk: Add GDK_RENDERING environment variable

It's useful for debugging rendering issues, both correctness and
performance wise.

See the added documentation for what it does and how it works.

1 files changed, 13 insertions, 0 deletions

diff --git a/gdk/gdk.c b/gdk/gdk.c
index 43d45f50d2..16b4e74ca5 100644
--- a/gdk/gdk.c
+++ b/gdk/gdk.c
@@ -215,6 +215,8 @@ gdk_add_option_entries_libgtk_only (GOptionGroup *group)
 void
 gdk_pre_parse_libgtk_only (void)
 {
+  const char *rendering_mode;
+
   gdk_initialized = TRUE;
 
   /* We set the fallback program class here, rather than lazily in
@@ -241,6 +243,17 @@ gdk_pre_parse_libgtk_only (void)
       g_unsetenv ("GDK_NATIVE_WINDOWS");
     }
 
+  rendering_mode = g_getenv ("GDK_RENDERING");
+  if (rendering_mode)
+    {
+      if (g_str_equal (rendering_mode, "similar"))
+        _gdk_rendering_mode = GDK_RENDERING_MODE_SIMILAR;
+      else if (g_str_equal (rendering_mode, "image"))
+        _gdk_rendering_mode = GDK_RENDERING_MODE_IMAGE;
+      else if (g_str_equal (rendering_mode, "recording"))
+        _gdk_rendering_mode = GDK_RENDERING_MODE_RECORDING;
+    }
+
   g_type_init ();
 
   /* Do any setup particular to the windowing system */