UIImage加阴影

#import <QuartzCore/QuartzCore.h>
一、给图片加上阴影 

 UIImageView*pageContenterImageView = [[UIImageView alloc]initWithImage:[UIImage imageNamed:@"onePageApple.png"]];
        
        //添加边框
        
        CALayer*layer = [pageContenterImageView layer];
        
        layer.borderColor= [[UIColor whiteColor]CGColor];
        
        layer.borderWidth=0.0f;
        
        //添加四个边阴影
        
        pageContenterImageView.layer.shadowColor= [UIColor blackColor].CGColor;
        
        pageContenterImageView.layer.shadowOffset=CGSizeMake(0,0);
        
        pageContenterImageView.layer.shadowOpacity=0.5; 
        
        pageContenterImageView.layer.shadowRadius=5.0;
        
        //添加两个边阴影
        
        //pageContenterImageView.layer.shadowColor = [UIColor blackColor].CGColor;
        
        //    pageContenterImageView.layer.shadowOffset = CGSizeMake(2, 2);
        
        //    pageContenterImageView.layer.shadowOpacity = 0.5; 
        
        //    pageContenterImageView.layer.shadowRadius = 2.0;
        
        //-------------
        
        阴影渲染会严重消耗内存 ,导致程序咔叽.
        
        /*阴影效果*/
        
        //添加边框
        
        CALayer*layer = [self.pageContenter layer];
        
        layer.borderColor= [[UIColorwhiteColor]CGColor];
        
        layer.borderWidth=0.0f;
        
        //添加四个边阴影
        
        self.pageContenter.layer.shadowColor= [UIColorblackColor].CGColor;//阴影颜色
        
        self.pageContenter.layer.shadowOffset=CGSizeMake(0,0);//阴影偏移
        
        self.pageContenter.layer.shadowOpacity=0.5;//阴影不透明度
        
        self.pageContenter.layer.shadowRadius=5.0;//阴影半径
        
        //添加两个边阴影
        
        //self.pageContenter.layer.shadowColor = [UIColor blackColor].CGColor;
        
        //self.pageContenter.layer.shadowOffset = CGSizeMake(2, 2);
        
        //self.pageContenter.layer.shadowOpacity = 0.5; 
        
        //self.pageContenter.layer.shadowRadius = 2.0; 

二、给视图加上阴影

 UIView * content=[[UIView alloc] initWithFrame:CGRectMake(100, 250, 503, 500)]; 
    content.backgroundColor=[UIColor orangeColor];
    //content.layer.shadowOffset=10;
    
    
    content.layer.shadowOffset = CGSizeMake(5, 3);
    content.layer.shadowOpacity = 0.6;
    content.layer.shadowColor = [UIColor blackColor].CGColor;
    
    
    [self.window addSubview:content];