Detecting 'Mouse_Over' for irregular shapes

Hi

I need a very accurate method of detecting when the mouse is over particular regions in a given bitmap. I can't use labels etc as these won't allow me to match my shapes accurately enough!

I had used RGB values from a 2nd bitmap taking X and Y values from the target bitmap......this is OK as long as the Colour is True-Colour ( for me anyway) else it fails!!

Is there a technique an OCX for this task?

Regard Peter