ios - 裁剪一个70*70px的正方形为正方形

Question

在我使用下面的代码制作我的 UIImage 之前:

image.layer.cornerRadius = button.frame.size.width / 2;
image.clipsToBounds = YES;

图像大小为 70*70px，我想在 CGImageContext 中执行相同操作并保存结果，而不是像上面那样设置圆角半径，因为这会显着降低 UI 速度。在 CGImageContext 中有没有办法做到这一点？谢谢

Answer 1

您可以设置一个圆角蒙版而不是圆角，这会降低性能。

swift :

let roundMaskLayer = CAShapeLayer()
roundMaskLayer.path = UIBezierPath(roundedRect: self.YOURIMAGEVIEW.bounds, byRoundingCorners: UIRectCorner.AllCorners, cornerRadii: CGSize(width: self.YOURIMAGEVIEW.frame.size.width/2,height: self.YOURIMAGEVIEW.frame.size.height/2)).CGPath
self.YOURIMAGEVIEW.layer.mask = roundMaskLayer
self.YOURIMAGEVIEW.layer.masksToBounds = true

objective-C :

CAShapeLayer *roundMaskLayer = [[CAShapeLayer alloc] init];
roundMaskLayer.path = (__bridge CGPathRef)([UIBezierPath bezierPathWithRoundedRect:self.YOURIMAGEVIEW.bounds byRoundingCorners:UIRectCornerAllCorners cornerRadii:CGSizeMake(self.YOURIMAGEVIEW.bounds.size.width/2, self.YOURIMAGEVIEW.bounds.size.height/2)]);
self.YOURIMAGEVIEW.layer.mask = roundMaskLayer;
self.YOURIMAGEVIEW.layer.masksToBounds = true;