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.