[Window] Set up real transparency if possible

This adds the RGBA colormap code so that it is possible to have true
transparency if you have a compositor enabled.

diff --git a/tilda-window.c b/tilda-window.c
index b0adcfd..7cff702 100644 (file)
--- a/tilda-window.c
+++ b/tilda-window.c
@@ -107,6 +107,30 @@ tilda_window_remove_term (TildaWindow *tw, gint terminal_number)
        return TRUE;
 }
 
+/**
+ * This sets up the given TildaWindow for the capability of real
+ * transparency, if the X server is capable of it. */
+static void
+tilda_window_setup_real_transparency (TildaWindow *self)
+{
+       GdkScreen *screen;
+       GdkColormap *colormap;
+
+       screen = gtk_widget_get_screen (GTK_WIDGET(self->window));
+       colormap = gdk_screen_get_rgba_colormap (screen);
+
+       /* If possible, set the RGBA colormap so VTE can use real alpha
+        * channels for transparency. */
+       if (colormap != NULL && gdk_screen_is_composited (screen))
+       {
+               gtk_widget_set_colormap (GTK_WIDGET(self->window), colormap);
+               self->have_real_transparency = TRUE;
+               return;
+       }
+
+       self->have_real_transparency = FALSE;
+}
+
 static void
 tilda_window_dbus_register_object (TildaWindow *tw)
 {
@@ -126,6 +150,8 @@ static GObjectClass *parent_class = NULL;
 
 enum tilda_window_properties {
        TILDA_WINDOW_NUMBER = 1,
+
+       TILDA_WINDOW_HAVE_REAL_TRANSPARENCY,
 };
 
 static void
@@ -159,6 +185,11 @@ tilda_window_set_property (GObject      *object,
                        g_print ("window number: %d\n", self->number);
                        break;
 
+               case TILDA_WINDOW_HAVE_REAL_TRANSPARENCY:
+                       self->have_real_transparency = g_value_get_boolean (value);
+                       g_print ("window have real transp: %d\n", self->have_real_transparency);
+                       break;
+
                default:
                        /* We don't have this property */
                        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
@@ -180,6 +211,10 @@ tilda_window_get_property (GObject    *object,
                        g_value_set_int (value, self->number);
                        break;
 
+               case TILDA_WINDOW_HAVE_REAL_TRANSPARENCY:
+                       g_value_set_boolean (value, self->have_real_transparency);
+                       break;
+
                default:
                        /* We don't have this property */
                        G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
@@ -211,6 +246,9 @@ tilda_window_constructor (GType                  type,
        /* Register this object with DBus */
        tilda_window_dbus_register_object (self);
 
+       /* Try to set up real transparency */
+       tilda_window_setup_real_transparency (self);
+
        gtk_container_add (GTK_CONTAINER(self->window), self->notebook);
        gtk_widget_show (self->notebook);
 
@@ -299,6 +337,13 @@ tilda_window_class_init (gpointer g_class,
                                                                         TILDA_WINDOW_NUMBER,
                                                                         pspec);
 
+       pspec = g_param_spec_boolean ("have-real-transparency",
+                                                                 NULL, NULL, FALSE, G_PARAM_READABLE);
+
+       g_object_class_install_property (gobject_class,
+                                                                        TILDA_WINDOW_HAVE_REAL_TRANSPARENCY,
+                                                                        pspec);
+
        /* TODO: more properties */
 
        /* Hook the TildaWindow type into DBus */

diff --git a/tilda-window.h b/tilda-window.h
index e11e17c..b8b408f 100644 (file)
--- a/tilda-window.h
+++ b/tilda-window.h
@@ -42,6 +42,8 @@ struct _TildaWindow {
        GPtrArray *terms;
 
        gint number;
+
+       gboolean have_real_transparency;
 };
 
 struct _TildaWindowClass {