IOS如何使用CAShapeLayer实现复杂的View的遮罩效果

@implementation CAShapeLayer (ViewMask)

+ (instancetype)createMaskLayerWithView : (UIView *)view{

  CGFloat viewWidth = CGRectGetWidth(view.frame);
  CGFloat viewHeight = CGRectGetHeight(view.frame);

  CGFloat rightSpace = 10.;
  CGFloat topSpace = 15.;

  CGPoint point1 = CGPointMake(0, 0);
  CGPoint point2 = CGPointMake(viewWidth-rightSpace, 0);
  CGPoint point3 = CGPointMake(viewWidth-rightSpace, topSpace);
  CGPoint point4 = CGPointMake(viewWidth, topSpace);
  CGPoint point5 = CGPointMake(viewWidth-rightSpace, topSpace+10.);
  CGPoint point6 = CGPointMake(viewWidth-rightSpace, viewHeight);
  CGPoint point7 = CGPointMake(0, viewHeight);


  UIBezierPath *path = [UIBezierPath bezierPath];
  [path moveToPoint:point1];
  [path addLineToPoint:point2];
  [path addLineToPoint:point3];
  [path addLineToPoint:point4];
  [path addLineToPoint:point5];
  [path addLineToPoint:point6];
  [path addLineToPoint:point7];
  [path closePath];

  CAShapeLayer *layer = [CAShapeLayer layer];
  layer.path = path.CGPath;

  return layer;
}

@end

UIView *view = [[UIView alloc] initWithFrame:CGRectMake(40, 50, 80, 100)];
view.backgroundColor = [UIColor orangeColor];
[self.view addSubview:view];

CAShapeLayer *layer = [CAShapeLayer createMaskLayerWithView:view];
view.layer.mask = layer;