Detect collision between transparent UIImageviews

Question

I am searching for a pixel collision with two UIImageview with transparency.

The check should be done after an UIView was dragged and it should detect if the UIView overlaps another UIImageview. With CGRectIntersectsRect only the frames are compared. Maybe there is a solution of create a new UIImageview from the overlapped area and check if there is only transparency in it?

Maybe someone has another hint or solution?

Answer 1

您可以从CGRectIntersectsRect获取相交的帧rect，并为两个图像提取相交区域的Alpha通道值，如检索UIImage的像素alpha值所述 ，如果两者在同一位置上具有非零alpha，则碰撞为检测。