在CALayer的蒙版区域周围添加阴影

我正在屏蔽CAGradientLayer和CAShapeLayer，以便生成位于表格中某些行内的书签。在CALayer的蒙版区域周围添加阴影

enter image description here

 CGMutablePathRef path = CGPathCreateMutable(); 
     CGPathAddLines(path, 
         NULL, 
         (CGPoint[]){ 
          CGPointMake(8, 0), 
          CGPointMake(22, 0), 
          CGPointMake(22, 22), 
          CGPointMake(15, 16), 
          CGPointMake(8, 22) 
         }, 
         5); 
     CGPathCloseSubpath(path); 

     CAShapeLayer *mask = [CAShapeLayer layer]; 
     mask.fillColor = [UIColor redColor].CGColor; 
     mask.bounds = CGRectMake(0, 0, 30, 30); 
     mask.path = path; 
     mask.anchorPoint = CGPointMake(0, 0); 

     CGPathRelease(path); 

     CAGradientLayer *favoriteBadge = [CAGradientLayer layer]; 
     favoriteBadge.colors = 
      @[(id)[UIColor colorWithRed:.97f green:0.5f blue:0.1f alpha:1.f].CGColor, // orange 
       (id)[UIColor colorWithRed:1.f green:.8f blue:0.f alpha:1.f].CGColor]; // yellow 
     favoriteBadge.locations = @[@0.0, @1.0]; 
     favoriteBadge.bounds = CGRectMake(0, 0, 30, 30); 
     favoriteBadge.anchorPoint = CGPointMake(1, 0); 
     favoriteBadge.position = CGPointMake(self.bounds.size.width, 0); 
     favoriteBadge.mask = mask; 
     // FIXME: This shadow is not being applied 
     favoriteBadge.shadowColor = [UIColor colorWithRed:.97f green:0.5f blue:0.1f alpha:1.f].CGColor; 
     favoriteBadge.shadowOpacity = 1.f;

这看起来太平坦，所以我想与周围的形状本身阴影完成这一关。我已经尝试在图层上启用阴影，但似乎没有得到应用。我认为它被应用在不在形状内的区域。我怎样才能为形状本身添加阴影？

我可以复制图层，使图层变暗并将其位置偏移几个像素，但是当CoreAnimation可能对我更有效时，它会感到浪费。

来源

2013-02-03 d11wtq

+1很好地问道+ ID喜欢太了解：DI始终将图像和借鉴的东西自己.. –