如何在Objective-C的蒙版图像上添加没有蒙版的边框

Question

I have UIImageView with added mask to it's layer. And after that I want to add border to the image. But, looks like mask applying to the border also, because it's changing color (should be strong white, w\\o mask).

My code for doing this looking as

// Mask
CALayer *layer = [CALayer layer];
layer.frame = _photo.bounds;
layer.backgroundColor = [UIColor colorWithWhite:0.f alpha:.5f].CGColor;
[_photo.layer setMask:layer];

_photo.layer.cornerRadius = _photo.frame.size.width / 2;
_photo.layer.masksToBounds = YES;
_photo.clipsToBounds = YES;

// Border
_photo.layer.borderColor = [[UIColor whiteColor] CGColor];
_photo.layer.borderWidth = 2.0;

Image w\\o mask applied: Result is next:

How I can add border without changing it's color during mask apply?

Answer 1

I suspect you can't (easily) stop the layer's mask from also masking the layer's border. That being the case, I'd suggest creating a second view or layer just for the border, in front of _photo but outside its view hierarchy. You can then give that second layer the same bounds, corner radius and border as _photo 's layer without the mask applying to it.