When my project is in idle-mode, the screen displays an analog clock face. The hands of the clock are on top of a background image, so each minute I update the clock by redrawing the image and then the hour and minute hands over the image.
I would like to add a second hand, but redrawing the image each second to do so is not reasonable.
On my PC, there is a function called ReversePixels() which makes moving a hand easy. I just draw the hand with ReversePixels() over the background. Then to move the hand, I draw in the same location again with ReversePixels() which makes the hand disappear by reversing all pixels back to what they were before I first drew the hand. Then I call ReversePixels() again at the hand's new location. (Redrawing the background image is never necessary.)
However, I don't see a ReversePixels() type of function to use on my Arduino project. Does anyone know a way to do this so I can add the second hand?