http://groups.google.com/group/android-framework/browse_thread/thread/ffe7dacf83567b7b
Sparks.. For overlay interface, the hardware driver is responsible for scaling, rotation, etc. SurfaceFlinger just leaves a whole in the 2D composited frame (black pixels with alpha = 0) to allow overlay surface to show through the 2D surfaces. To be clear, this means that the video overlay is behind the 2D overlay. I believe there are provisions for chroma-key if the overlay doesn't support an alpha channel. Hi It appears that I can't reply to the discussion above previously called 'About the libhardware and overlay hardware interface.' From the discussion it appears that a video overlay is displayed behind the sufaceflinger's composited frame. When using overlays, the discussion states that the surfaceflinger leaves a hole with alpha=0 and pixels = black, but the discussion it also implies that an overlay may have an alpha channel. If the surfaceflinger leaves a hole, then what use is the overlay alpha because there will be no colors to multiply. Surely the surfaceflinger does not always leave a hole? and can have color pixels so that the surfaceflinger's composted frame can be alpha blended with an overlay frame using hardware? If this is the case can a composted frame have an alpha value so that the hardware knows how to multiply the foreground surface with the background video overlay? or does the overlay always have to have the alpha? Thanks Chris --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "android-framework" group. To post to this group, send email to android-framework@googlegroups.com To unsubscribe from this group, send email to android-framework+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/android-framework?hl=en -~----------~----~----~----~------~----~------~--~---