Question

I have a UIView has some labels and buttons on it.

Next I also have a image which has a square area that is transparent, now
if I create a UIImageView and add this image which has transparent regions I am not able to see the background view (which has buttons and labels) through this transparent image.

If I play with the alpha value that doesn’t work as intended which is to see the transparent regions exactly as it would have appeared on the UIView which has the labels and buttons.

UIImage* image = [UIImage imageNamed:@"TI1.jpg"];
UIImageView* imageView = [[UIImageView alloc] initWithImage:image];
[self.view addSubview:imageView];

Also I would be interested to know if there is other way to achieve what I am trying to achieve.

Basically I want to highlight a certain area of the view which has buttons/labels and make the rest of the area greyed out. My idea was to have this UIImageView with transparent regions in image to achieve that.

Thanks
Ankur

Answer 1

Try setting imageView.opaque = NO;

UIImageView inherits from UIView. According to that class’s docs:

This property provides a hint to the drawing system as to how it
should treat the view. If set to YES, the drawing system treats the
view as fully opaque, which allows the drawing system to optimize some
drawing operations and improve performance. If set to NO, the drawing
system composites the view normally with other content. The default
value of this property is YES.

Also, not sure that JPG even supports transparency, so try exporting the image as a PNG to ensure you get the results you’re looking for.