在CALayer的蒙版區域周圍添加陰影

我正在屏蔽CAGradientLayer和CAShapeLayer，以便生成位於表格中某些行內的書籤。在CALayer的蒙版區域周圍添加陰影

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;

這看起來太平坦，所以我想與周圍的形狀本身陰影完成這一關。我已經嘗試在圖層上啓用陰影，但似乎沒有得到應用。我認爲它被應用在不在形狀內的區域。我怎樣才能爲形狀本身添加陰影？

我可以複製圖層，使圖層變暗並將其位置偏移幾個像素，但是當CoreAnimation可能對我更有效時，它會感到浪費。

來源

2013-02-03 d11wtq

+1很好地問道+ ID喜歡太瞭解：DI始終將圖像和借鑑的東西自己.. –