iPhone应用程序中UIView中具有透明部分的背景图片

Question

Actually i am displaying events in calendar and for that i am adding subviews for events in UIScrollview. now i want to make some portion transparent in my particular event. Please check below image.

so i want to make that background image of event transparent with particular frame. Let me know if you have any idea about this or any alternative for that.

Answer 1

Here is a basic solution to clear a frame in a view using a custom drawLayer:inContext: method for your eventView custom class (the class that draws your event). Of course you have to inherit a class from UIView before (eg. MyEventViewClass). You also have to set the opaque property to NO

-(void)drawLayer:(CALayer*)layer inContext:(CGContextRef)context
{
       // Fill the bg with the color you want (here it is gray)
       // You can also draw an image (CGContextDrawImage:)
    CGContextSetFillColorWithColor(context, [UIColor grayColor].CGColor);
    CGContextFillRect(context, self.bounds);

      // Then clear the frame
    CGContextSetBlendMode(context, kCGBlendModeClear);
    CGContextFillRect(context, frameToClear);
}

Is it clear ? ;)