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, 22 insertions, 15 deletions

diff --git a/gtk/gtksettings.c b/gtk/gtksettings.c
index 64912ceeaf..7549c8d9ab 100644
--- a/gtk/gtksettings.c
+++ b/gtk/gtksettings.c
@@ -2944,24 +2944,31 @@ settings_update_resolution (GtkSettings *settings)
   const char *scale_env;
   double scale;
 
-  g_object_get (settings,
-                "gtk-xft-dpi", &dpi_int,
-                NULL);
+  /* We handle this here in the case that the dpi was set on the GtkSettings
+   * object by the application. Other cases are handled in
+   * xsettings-client.c:read-settings(). See comment there for the rationale.
+   */
+  if (priv->property_values[PROP_XFT_DPI - 1].source == GTK_SETTINGS_SOURCE_APPLICATION)
+    {
+      g_object_get (settings,
+                    "gtk-xft-dpi", &dpi_int,
+                    NULL);
 
-  if (dpi_int > 0)
-    dpi = dpi_int / 1024.;
-  else
-    dpi = -1.;
+      if (dpi_int > 0)
+        dpi = dpi_int / 1024.;
+      else
+        dpi = -1.;
 
-  scale_env = g_getenv ("GDK_DPI_SCALE");
-  if (scale_env)
-    {
-      scale = g_ascii_strtod (scale_env, NULL);
-      if (scale != 0 && dpi > 0)
-	dpi *= scale;
-    }
+      scale_env = g_getenv ("GDK_DPI_SCALE");
+      if (scale_env)
+        {
+          scale = g_ascii_strtod (scale_env, NULL);
+          if (scale != 0 && dpi > 0)
+            dpi *= scale;
+        }
 
-  gdk_screen_set_resolution (priv->screen, dpi);
+      gdk_screen_set_resolution (priv->screen, dpi);
+    }
 }
 
 static void