PhoshShell: Make background surface span the whole output

The background will make sure to not draw over/under panels.

Closes: #6
Signed-off-by: Guido Günther <guido.gunther@puri.sm>

src/background.c

@@ -45,8 +45,7 @@ image_background (GdkPixbuf *image, guint width, guint height)
   bg = gdk_pixbuf_new_from_xpm_data (xpm_data);
   scaled_bg = gdk_pixbuf_scale_simple (bg,
                                        width,
-                                       /* since we can't offset the pixmap */
-                                       height + PHOSH_PANEL_HEIGHT,
+                                       height,
                                        GDK_INTERP_BILINEAR);
   g_object_unref (bg);
 
@@ -107,7 +106,7 @@ load_background (PhoshBackground *self,
   if (!image)
     image = gdk_pixbuf_new_from_xpm_data (xpm_data);
 
-  g_object_get (self, "width", &width, "height", &height, NULL);
+  phosh_shell_get_usable_area (phosh_shell_get_default (), NULL, NULL, &width, &height);
   self->pixbuf = image_background (image, width, height);
 
   /* force background redraw */

src/shell.c

@@ -382,16 +382,14 @@ background_create (PhoshShell *self)
   PhoshWayland *wl = phosh_wayland_get_default();
   PhoshShellPrivate *priv = phosh_shell_get_instance_private (self);
   PhoshMonitor *monitor;
-  gint width, height;
 
   monitor = phosh_shell_get_primary_monitor (self);
   g_return_if_fail (monitor);
-  phosh_shell_get_usable_area (self, NULL, NULL, &width, &height);
 
-  /* set it up as the background */
+  /* background spans the whole monitor */
   priv->background = PHOSH_LAYER_SURFACE (phosh_background_new (
     phosh_wayland_get_zwlr_layer_shell_v1(wl),
-    monitor->wl_output, width, height));
+    monitor->wl_output, monitor->width, monitor->height));
   gtk_widget_show (GTK_WIDGET (priv->background));
 }