[gnome-control-center] bgo#590823 - RANDR - Automatically turn on outputs which support Mirror Screens

[Federico Mena Quintero <federico src gnome org>]

commit 6d40eb2648abfe4ff47cb491b899e5cc41cb7c60
Author: Federico Mena Quintero <federico novell com>
Date:   Wed Dec 9 15:59:11 2009 -0600

    bgo#590823 - RANDR - Automatically turn on outputs which support Mirror Screens
    
    Previously, outputs could remain off if the user just selected Mirror Screens.
    Now we automatically turn on all the outputs which support the clone mode,
    to avoid extra work on the part of the user.
    
    Signed-off-by: Federico Mena Quintero <federico novell com>

 capplets/display/xrandr-capplet.c |   79 +++++++++++++++++++++++++++++++++++++
 1 files changed, 79 insertions(+), 0 deletions(-)
---
diff --git a/capplets/display/xrandr-capplet.c b/capplets/display/xrandr-capplet.c
index 5a8b5b1..49458ad 100644
--- a/capplets/display/xrandr-capplet.c
+++ b/capplets/display/xrandr-capplet.c
@@ -858,6 +858,69 @@ lay_out_outputs_horizontally (App *app)
 
 }
 
+/* FIXME: this function is copied from gnome-settings-daemon/plugins/xrandr/gsd-xrandr-manager.c.
+ * Do we need to put this function in gnome-desktop for public use?
+ */
+static gboolean
+get_clone_size (GnomeRRScreen *screen, int *width, int *height)
+{
+        GnomeRRMode **modes = gnome_rr_screen_list_clone_modes (screen);
+        int best_w, best_h;
+        int i;
+
+        best_w = 0;
+        best_h = 0;
+
+        for (i = 0; modes[i] != NULL; ++i) {
+                GnomeRRMode *mode = modes[i];
+                int w, h;
+
+                w = gnome_rr_mode_get_width (mode);
+                h = gnome_rr_mode_get_height (mode);
+
+                if (w * h > best_w * best_h) {
+                        best_w = w;
+                        best_h = h;
+                }
+        }
+
+        if (best_w > 0 && best_h > 0) {
+                if (width)
+                        *width = best_w;
+                if (height)
+                        *height = best_h;
+
+                return TRUE;
+        }
+
+        return FALSE;
+}
+
+static gboolean
+output_info_supports_mode (App *app, GnomeOutputInfo *info, int width, int height)
+{
+    GnomeRROutput *output;
+    GnomeRRMode **modes;
+    int i;
+
+    if (!info->connected)
+	return FALSE;
+
+    output = gnome_rr_screen_get_output_by_name (app->screen, info->name);
+    if (!output)
+	return FALSE;
+
+    modes = gnome_rr_output_list_modes (output);
+
+    for (i = 0; modes[i]; i++) {
+	if (gnome_rr_mode_get_width (modes[i]) == width
+	    && gnome_rr_mode_get_height (modes[i]) == height)
+	    return TRUE;
+    }
+
+    return FALSE;
+}
+
 static void
 on_clone_changed (GtkWidget *box, gpointer data)
 {
@@ -869,6 +932,7 @@ on_clone_changed (GtkWidget *box, gpointer data)
     if (app->current_configuration->clone)
     {
 	int i;
+	int width, height;
 
 	for (i = 0; app->current_configuration->outputs[i]; ++i)
 	{
@@ -878,6 +942,21 @@ on_clone_changed (GtkWidget *box, gpointer data)
 		break;
 	    }
 	}
+
+	/* Turn on all the connected screens that support the best clone mode.
+	 * The user may hit "Mirror Screens", but he shouldn't have to turn on
+	 * all the required outputs as well.
+	 */
+
+	get_clone_size (app->screen, &width, &height);
+
+	for (i = 0; app->current_configuration->outputs[i]; i++) {
+	    if (output_info_supports_mode (app, app->current_configuration->outputs[i], width, height)) {
+		app->current_configuration->outputs[i]->on = TRUE;
+		app->current_configuration->outputs[i]->width = width;
+		app->current_configuration->outputs[i]->height = height;
+	    }
+	}
     }
     else
     {