Setting A CGContext Transparent Background

Question

I am still struggling with drawing a line with CGContext. I have actually go to line to draw, but now I need the background of the Rect to be transparent so the existing ba

Answer 1

CGContextClearRect(context,rect) 

If the provided context is a window or bitmap context, Quartz effectively clears the rectangle. For other context types, Quartz fills the rectangle in a device-dependent manner. However, you should not use this function in contexts other than window or bitmap contexts.