設(shè)置控件圓角，只設(shè)置上面兩個角的圓角，下面兩個角依然是直角，如圖效果：

代碼（通過貝塞爾曲線重繪layer層）：

UIImageView *picImageView = [[UIImageView alloc] initWithFrame:CGRectMake(100, 100, 100, 100)];  
picImageView.backgroundColor = [UIColor greenColor];  
[self.view addSubview:picImageView];  
          
// UIRectCornerBottomRight通過這個設(shè)置 
UIBezierPath *maskPath = [UIBezierPath bezierPathWithRoundedRect:picImageView.bounds 
                                               byRoundingCorners:UIRectCornerTopLeft|UIRectCornerTopRight 
                                                     cornerRadii:CGSizeMake(10, 10)];  
      
CAShapeLayer *maskLayer = [CAShapeLayer layer];  
maskLayer.frame = picImageView.bounds;  
maskLayer.path = maskPath.CGPath;  
      
picImageView.layer.mask = maskLayer;