Handle resolution changes in the GDK backend code

gdk_x11_display_set_window_scale() affects the interpretation of the
Xft/DPI XSETTING - it is substituted inside GDK with the value of
Gdk/UnscaledDPI xsetting. However, this change is not propagated to
GTK+ and from GTK+ back to gdk_screen_set_resolution() until the
main loop is run.

Fix this by handling the screen resolution directly in gdk/x11.
This requires duplication of code between GDK and GTK+ since we still
have to handle DPI in GTK+ in the case that GdkSettings:gtk-xft-dpi
is set by the application.

https://bugzilla.gnome.org/show_bug.cgi?id=733076

1 files changed, 25 insertions, 0 deletions

diff --git a/gdk/gdkscreen.c b/gdk/gdkscreen.c
index e2cbfb7d0d..cc170c5b4b 100644
--- a/gdk/gdkscreen.c
+++ b/gdk/gdkscreen.c
@@ -462,6 +462,31 @@ gdk_screen_set_resolution (GdkScreen *screen,
   if (dpi < 0)
     dpi = -1.0;
 
+  screen->resolution_set = TRUE;
+
+  if (screen->resolution != dpi)
+    {
+      screen->resolution = dpi;
+
+      g_object_notify (G_OBJECT (screen), "resolution");
+    }
+}
+
+/* Just like gdk_screen_set_resolution(), but doesn't change
+ * screen->resolution. This is us to allow us to distinguish
+ * resolution changes that the backend picks up from resolution
+ * changes made through the public API - perhaps using
+ * g_object_set(<GtkSetting>, "gtk-xft-dpi", ...);
+ */
+void
+_gdk_screen_set_resolution (GdkScreen *screen,
+                            gdouble    dpi)
+{
+  g_return_if_fail (GDK_IS_SCREEN (screen));
+
+  if (dpi < 0)
+    dpi = -1.0;
+
   if (screen->resolution != dpi)
     {
       screen->resolution = dpi;