Whenever some area of the window is invalidated (directly in the
window or in a child window) this gets called with @region in
the coordinate space of @window. You can use @region to just
keep track of the dirty region, or you can actually change
@region in case you are doing display tricks like showing
a child in multiple places.
Whenever some area of the window is invalidated (directly in the window or in a child window) this gets called with @region in the coordinate space of @window. You can use @region to just keep track of the dirty region, or you can actually change @region in case you are doing display tricks like showing a child in multiple places.