1 files changed, 144 insertions, 0 deletions
diff --git a/sgm-overlay-scrolling-override.c b/sgm-overlay-scrolling-override.c
new file mode 100644
index 0000000..13116af
--- /dev/null
+++ b/sgm-overlay-scrolling-override.c
@@ -0,0 +1,144 @@
+#include <gtk/gtk.h>
+#include <glib.h>
+
+
+enum
+{
+  /*
+   * In GTK+ 3.24.9 and later, the "overlay-scrolling" property is assigned
+   * a property number of 85.  We might as well follow that convention here
+   * and avoid any property number collisions.
+   */
+  PROP_OVERLAY_SCROLLING = 85
+};
+
+
+static gboolean     overlay_scrolling_enabled = TRUE;
+
+static GParamSpec * gtk_overlay_scrolling_pspec;
+
+
+static void (*original_gtk_settings_set_property) (GObject      *object,
+                                                   guint         property_id,
+                                                   const GValue *value,
+                                                   GParamSpec   *pspec);
+
+static void (*original_gtk_settings_get_property) (GObject      *object,
+                                                   guint         property_id,
+                                                   const GValue *value,
+                                                   GParamSpec   *pspec);
+
+
+static void overridden_gtk_settings_set_property (GObject      *object,
+                                                  guint         property_id,
+                                                  const GValue *value,
+                                                  GParamSpec   *pspec);
+
+static void overridden_gtk_settings_get_property (GObject      *object,
+                                                  guint         property_id,
+                                                  const GValue *value,
+                                                  GParamSpec   *pspec);
+
+
+G_MODULE_EXPORT const char *
+g_module_check_init (GModule *module)
+{
+  /*
+   * Exit immediately on GTK+ versions prior to 3.15.0, since overlay
+   * scrolling hadn't been introduced yet!
+   */
+  if (gtk_check_version (3,15,0) != NULL)
+  {
+    return "Your version of GTK+ is too old to support overlay scrolling.\n"
+           "This module is thus unnecessary and you should remove it.";
+  }
+
+  /*
+   * Similarly, a property was introduced in GTK+ 3.24.9 to disable overlay
+   * scrolling globally, making this module redundant.
+   */
+  else if (gtk_check_version (3,24,9) == NULL)
+  {
+    return "Your version of GTK+ already supports globally disabling overlay scrolling.\n"
+           "This module is thus redundant and you should remove it.";
+  }
+
+  /*
+   * Otherwise, this module is useful for the current version of GTK+, so
+   * proceed with loading it.
+   */
+  else
+  {
+    g_module_make_resident (module);
+    return NULL;
+  }
+}
+
+G_MODULE_EXPORT int
+gtk_module_init (gint * argc, char *** argv)
+{
+  GtkSettingsClass *gtk_settings_class;
+  GtkScrolledWindowClass *gtk_scrolled_window_class;
+
+  (void) argc;
+  (void) argv;
+
+  gtk_settings_class = g_type_class_ref (GTK_TYPE_SETTINGS);
+
+  gtk_overlay_scrolling_pspec = g_param_spec_boolean ("gtk-overlay-scrolling",
+                                                      "Overlay Scrolling",
+                                                      "Whether to enable overlay scrolling mode globally",
+                                                      overlay_scrolling_enabled,
+                                                      G_PARAM_READWRITE);
+
+  g_object_class_install_property (gtk_settings_class,
+                                   PROP_OVERLAY_SCROLLING,
+                                   gtk_overlay_scrolling_pspec);
+
+  original_gtk_settings_set_property = G_OBJECT_CLASS (gtk_settings_class)->set_property;
+  G_OBJECT_CLASS (gtk_settings_class)->set_property = overridden_gtk_settings_class_set_property;
+
+  original_gtk_settings_get_property = G_OBJECT_CLASS (gtk_settings_class)->get_property;
+  G_OBJECT_CLASS (gtk_settings_class)->get_property = overridden_gtk_settings_class_get_property;
+
+  g_type_class_unref (gtk_settings_class);
+
+
+  
+
+  return 0;
+}
+
+
+static void overridden_gtk_settings_set_property (GObject      *object,
+                                                  guint         property_id,
+                                                  const GValue *value,
+                                                  GParamSpec   *pspec)
+{
+  switch (property_id)
+  {
+  case PROP_OVERLAY_SCROLLING:
+    overlay_scrolling_enabled = g_value_get_boolean (value);
+    break;
+
+  default:
+    original_gtk_settings_set_property (object, property_id, value, pspec);
+  }
+}
+
+
+static void overridden_gtk_settings_get_property (GObject      *object,
+                                                  guint         property_id,
+                                                  const GValue *value,
+                                                  GParamSpec   *pspec)
+{
+  switch (property_id)
+  {
+  case PROP_OVERLAY_SCROLLING:
+    g_value_set_boolean (value, overlay_scrolling_enabled);
+    break;
+
+  default:
+    original_gtk_settings_get_property (object, property_id, value, pspec);
+  }
+}