Ok lets see if I can explain what I will soon try to do.
I am working on a smal cad/cam program that lets me draw things like lines and arcs. If you are thinking paint but more advanced you are pretty close to what it will look like. I am storing everything drawn in a CObArray and I am using a class named CEntity. My problems is that I want to be able to identify the right instance from my CEntity class when the mouse gets close to coresponding entity on the canvas. How can I extract info from my CObArray (on the fly) when the mouse is close to a pixel representing an entity? I am not looking for code or anything specific, just ideas on how I can approach this problem. Hope all this made sense.