iPhone之为UIView设置阴影(CALayer的shadowColor，shadowOffset，shadowOpacity，shadowRadius,shadowPath属性)

效果图：

以下代码实现：

第一个图片的代码

 //加阴影--任海丽编辑
     _imageView.layer.shadowColor = [UIColor blackColor].CGColor;//shadowColor阴影颜色
     _imageView.layer.shadowOffset = CGSizeMake(4,4);//shadowOffset阴影偏移,x向右偏移4，y向下偏移4，默认(0, -3),这个跟shadowRadius配合使用
     _imageView.layer.shadowOpacity = 0.8;//阴影透明度，默认0
     _imageView.layer.shadowRadius = 4;//阴影半径，默认3

第二个图片的代码

 _imageView1.layer.shadowColor = [UIColor yellowColor].CGColor;//shadowColor阴影颜色
 _imageView1.layer.shadowOffset = CGSizeMake(0,0);//shadowOffset阴影偏移，默认(0, -3),这个跟shadowRadius配合使用
 _imageView1.layer.shadowOpacity = 1;//阴影透明度，默认0
 _imageView1.layer.shadowRadius = 3;//阴影半径，默认3

 //路径阴影
 UIBezierPath *path = [UIBezierPath bezierPath];

 float width = _imageView1.bounds.size.width;
 float height = _imageView1.bounds.size.height;
 float x = _imageView1.bounds.origin.x;
 float y = _imageView1.bounds.origin.y;
 float addWH = 10;

 CGPoint topLeft      = _imageView1.bounds.origin;
 CGPoint topMiddle = CGPointMake(x+(width/2),y-addWH);
 CGPoint topRight     = CGPointMake(x+width,y);

 CGPoint rightMiddle = CGPointMake(x+width+addWH,y+(height/2));

 CGPoint bottomRight  = CGPointMake(x+width,y+height);
 CGPoint bottomMiddle = CGPointMake(x+(width/2),y+height+addWH);
 CGPoint bottomLeft   = CGPointMake(x,y+height);


 CGPoint leftMiddle = CGPointMake(x-addWH,y+(height/2));

 [path moveToPoint:topLeft];
 //添加四个二元曲线
 [path addQuadCurveToPoint:topRight
              controlPoint:topMiddle];
 [path addQuadCurveToPoint:bottomRight
              controlPoint:rightMiddle];
 [path addQuadCurveToPoint:bottomLeft
              controlPoint:bottomMiddle];
 [path addQuadCurveToPoint:topLeft
              controlPoint:leftMiddle];
 //设置阴影路径
  _imageView1.layer.shadowPath = path.CGPath;

ok！