Window.beginDrawFrame

Indicates that you are beginning the process of redrawing @region on @window, and provides you with a #GdkDrawingContext.

If @window is a top level #GdkWindow, backed by a native window implementation, a backing store (offscreen buffer) large enough to contain @region will be created. The backing store will be initialized with the background color or background surface for @window. Then, all drawing operations performed on @window will be diverted to the backing store. When you call gdk_window_end_frame(), the contents of the backing store will be copied to @window, making it visible on screen. Only the part of @window contained in @region will be modified; that is, drawing operations are clipped to @region.

The net result of all this is to remove flicker, because the user sees the finished product appear all at once when you call gdk_window_end_draw_frame(). If you draw to @window directly without calling gdk_window_begin_draw_frame(), the user may see flicker as individual drawing operations are performed in sequence.

When using GTK+, the widget system automatically places calls to gdk_window_begin_draw_frame() and gdk_window_end_draw_frame() around emissions of the GtkWidget::draw signal. That is, if you’re drawing the contents of the widget yourself, you can assume that the widget has a cleared background, is already set as the clip region, and already has a backing store. Therefore in most cases, application code in GTK does not need to call gdk_window_begin_draw_frame() explicitly.

class Window
beginDrawFrame

Parameters

region Region

a Cairo region

Return: a #GdkDrawingContext context that should be used to draw the contents of the window; the returned context is owned by GDK.

Meta

Since

3.22