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  • Let me try to clarify.
    What I want to achieve is a 16 bit full-screen clockface.
    My understanding is that if the hand moves I need restore (at minimum) the area that was covered by the hand at the old position that will not be overwritten by drawing the new hand.
    So this is not about drawing the hand, it is about restoring the background.

    Of course one can rewrite the old background in full: expensive.
    Or you can rewrite only sections (as suggested by Abhigkar earlier in this thread) (bounding box based, but you would need images to draw)
    Or you can store the background of every hand position an redraw that one (that is the 60 background images I was suggesting before, note that the background might be different when the hand is at a different position (I just want to have an image as watchface
    Or you can restore the background based upon the "old hand": that is instead of rendering the hand, restore/re-render the background pixels that were covered when the hand was drawn at the previous position.

    Or, rephrasing the problem:
    Suppose as watchface I want to have a high-res image of my kid. When the minute hand moves from say 0 to 1 am looking for an efficient way (both CPU and RAM efficient) to restore the area that has been overwritten by the hand while at minute 0 after which I can write the hand for minute 1. To do this as efficient as possible, I would like to redraw only the pixels that are actually overwritten.

    Did I now express my problem better?


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