I have been trying to make some basic 2D cnc like simulator, with some rectangle that is shaped by tools etc. I want to make cursor, so the user know where the current position of tool is.

But i dont know how to do it, i tried to make function to save the current points colour, then to draw the cursor and then to fill these pixels with saved colours, but this is very bugged and slow. I also tried to make another bitmap that is transparent, but i also failed. So how to manage to write cursor that have X and Y coordinated and does not interfere with object already drawn on canvas? Thanks for any advice, I am very beginner (4 months)