GtkWidget::draw() - Document how to get the dirty region

Signed-off-by: Federico Mena Quintero's avatarFederico Mena Quintero <federico@gnome.org>
parent 8e80fd1a
......@@ -1805,6 +1805,13 @@ gtk_widget_class_init (GtkWidgetClass *klass)
* restore it. The signal emission takes care of calling cairo_save()
* before and cairo_restore() after invoking the handler.
*
* The signal handler will get a @cr with a clip region already set to the
* widget's dirty region, i.e. to the area that needs repainting. Complicated
* widgets that want to avoid redrawing themselves completely can get the full
* extents of the clip region with gdk_cairo_get_clip_rectangle(), or they can
* get a finer-grained representation of the dirty region with
* cairo_copy_clip_rectangle_list().
*
* Returns: %TRUE to stop other handlers from being invoked for the event.
% %FALSE to propagate the event further.
*
......
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