UIbutton 和UIview 切单角

    UIButton * btn = [UIButton buttonWithType:UIButtonTypeCustom];
    btn.backgroundColor = [UIColor cyanColor];
    btn.frame = CGRectMake(100, 100, 100, 100);
    [self.view addSubview:btn];
    
    UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:btn.bounds      byRoundingCorners:UIRectCornerBottomLeft | UIRectCornerBottomRight    cornerRadii:CGSizeMake(10, 10)];
    CAShapeLayer *maskLayer = [[CAShapeLayer alloc] init];
    maskLayer.frame = btn.bounds;
    maskLayer.path = maskPath.CGPath;
    btn.layer.mask = maskLayer;

UIButton  UIView 同理。