view添加阴影
//@mg:masksToBounds必须为NO否者阴影没有效果
// cell.layer.masksToBounds = NO;
cell.layer.contentsScale = [UIScreen mainScreen].scale;
cell.layer.shadowOpacity = 0.15f;
cell.layer.shadowRadius = 2.0f;
cell.layer.shadowOffset = CGSizeMake(0,0);
cell.layer.shadowPath = [UIBezierPath bezierPathWithRect:cell.bounds].CGPath;
//设置缓存
cell.layer.shouldRasterize = YES;
//设置抗锯齿边缘
cell.layer.rasterizationScale = [UIScreen mainScreen].scale;