removed performance bottleneck where we measure the label text too many

	* libnautilus-extensions/nautilus-icon-canvas-item.c:
	(nautilus_icon_canvas_item_initialize),
	(invalidate_text_dimensions), (nautilus_icon_canvas_item_set_arg),
	(measure_label_text):
	removed performance bottleneck where we measure the label text too
	many times by making it use values cached in the item details.
	Added code to invalidate them at the appropriate times, and
	made measure_label_text short-circuit if they're valid.

1 files changed, 33 insertions, 1 deletions

diff --git a/libnautilus-private/nautilus-icon-canvas-item.c b/libnautilus-private/nautilus-icon-canvas-item.c
index 3eacaba1a..3a1b24851 100644
--- a/libnautilus-private/nautilus-icon-canvas-item.c
+++ b/libnautilus-private/nautilus-icon-canvas-item.c
@@ -279,6 +279,11 @@ nautilus_icon_canvas_item_initialize (NautilusIconCanvasItem *icon_item)
 
 	icon_item->details->is_renaming = FALSE;
 
+	/* invalidate cached text dimensions initially */
+	icon_item->details->text_width = -1;
+	icon_item->details->text_height = -1;
+	
+	/* set up the default font and size */
 	icon_item->details->smooth_font_size = 12;
 	icon_item->details->smooth_font = nautilus_scalable_font_get_default_font ();
 }
@@ -334,14 +339,26 @@ pixbuf_is_acceptable (GdkPixbuf *pixbuf)
 		&& gdk_pixbuf_get_bits_per_sample (pixbuf) == 8;
 }
 
+/* utility routine to invalidate the text width and height cached in the
+ * item details.
+ */
+static void
+invalidate_text_dimensions (NautilusIconCanvasItem *item)
+{
+	item->details->text_width = -1;
+	item->details->text_height = -1;
+}
+
 /* Set_arg handler for the icon item. */
 static void
 nautilus_icon_canvas_item_set_arg (GtkObject *object, GtkArg *arg, guint arg_id)
 {
+	NautilusIconCanvasItem *item;
 	NautilusIconCanvasItemDetails *details;
 	GdkFont *font;
 
-	details = NAUTILUS_ICON_CANVAS_ITEM (object)->details;
+	item =  NAUTILUS_ICON_CANVAS_ITEM (object);
+	details = item->details;
 
 	switch (arg_id) {
 
@@ -352,6 +369,8 @@ nautilus_icon_canvas_item_set_arg (GtkObject *object, GtkArg *arg, guint arg_id)
 
 		g_free (details->editable_text);
 		details->editable_text = g_strdup (GTK_VALUE_STRING (*arg));
+		
+		invalidate_text_dimensions (item);		
 		break;
 
 	case ARG_ADDITIONAL_TEXT:
@@ -361,6 +380,8 @@ nautilus_icon_canvas_item_set_arg (GtkObject *object, GtkArg *arg, guint arg_id)
 
 		g_free (details->additional_text);
 		details->additional_text = g_strdup (GTK_VALUE_STRING (*arg));
+		
+		invalidate_text_dimensions (item);		
 		break;
 
 	case ARG_FONT:
@@ -376,6 +397,8 @@ nautilus_icon_canvas_item_set_arg (GtkObject *object, GtkArg *arg, guint arg_id)
 			gdk_font_unref (details->font);
 		}
 		details->font = font;
+		
+		invalidate_text_dimensions (item);		
 		break;
 
 	case ARG_HIGHLIGHTED_FOR_SELECTION:
@@ -402,6 +425,7 @@ nautilus_icon_canvas_item_set_arg (GtkObject *object, GtkArg *arg, guint arg_id)
         case ARG_SMOOTH_FONT:
 		nautilus_icon_canvas_item_set_smooth_font (NAUTILUS_ICON_CANVAS_ITEM (object),
 							   NAUTILUS_SCALABLE_FONT (GTK_VALUE_OBJECT (*arg)));
+		invalidate_text_dimensions (item);				
 		break;
 
         case ARG_SMOOTH_FONT_SIZE:
@@ -862,6 +886,14 @@ draw_or_measure_label_text (NautilusIconCanvasItem *item,
 static void
 measure_label_text (NautilusIconCanvasItem *item)
 {
+	/* check to see if the cached values are still valid; if so, there's
+	 * no work necessary
+	 */
+	
+	if (item->details->text_width >= 0 && item->details->text_height >= 0) {
+		return;
+	}
+	
 	if (icon_canvas_item_is_smooth (item)) {
 		draw_or_measure_label_text_aa (item, NULL, 0, 0);
 	}