objective c - Highlighting or filling in empty white spaces of a UIViewController -

objective c - Highlighting or filling in empty white spaces of a UIViewController -

i have uiviewcontroller of white background , allows user color in uiimageview of color touch events. when done, way highlight or show uncolored areas (the remaining white areas) of uiimageview. there nice way implement this. have tried messing cgbitmap methods have not been successful without errors in code.

thanks!

could alter background color of uiviewcontroller?

objective-c image uiviewcontroller colors uiimageview