From 756a3bcc1fffd0cc85d570e61b874bbd620e4d95 Mon Sep 17 00:00:00 2001
From: "Ira W. Snyder" <devel@irasnyder.com>
Date: Mon, 14 Jan 2008 00:21:28 -0800
Subject: [PATCH] [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.
---
 tilda-window.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
 tilda-window.h |  2 ++
 2 files changed, 47 insertions(+)

diff --git a/tilda-window.c b/tilda-window.c
index b0adcfd..7cff702 100644
--- 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
--- a/tilda-window.h
+++ b/tilda-window.h
@@ -42,6 +42,8 @@ struct _TildaWindow {
 	GPtrArray *terms;
 
 	gint number;
+
+	gboolean have_real_transparency;
 };
 
 struct _TildaWindowClass {
-- 
2.25.1