I couldn't find a answer to this elsewhere, so...

I'm looking to create a GUI that supports pop-up windows. For example, if you wanted to pop-up a rectangular dialog box, you would normally need to read all the pixels in the desired rectangular area on the current canvas, and save them into RAM.

You would then draw the pop-up window onto your screen. When the pop-up was dismissed, you would restore the screen area with the copy that was previously saved into memory.

I'm looking at the GFX libraries, but don't see any support that would help.

Ideas welcome!