Patent attributes
A display window is attributed a layering attribute such that underlying display windows are blended with the layered display window and displayed on the display screen. In a first embodiment, the layered window and the underlying window are represented as bitmaps. Any overlapping portions of the underlying window bitmap are redirected to an underlay buffer and composited with the layered window bitmap according to a display order and an opacity level. In a second embodiment, the layered window and the underlying window are represented as hardware sprites. Graphics device hardware stores copies of each sprite and composites each sprite according to a display order and an opacity level. In either embodiment or in a combination of both, as the layered window is moved or resized, the stored data allows for updating the composite display without requiring system expensive display regenerations.
