IOS图片的两种处理：加阴影和变灰色

    

#import <QuartzCore/QuartzCore.h>

    //图片阴影

    UIImageView *img;

    [[img layer] setShadowOffset:CGSizeMake(5, 5)];

    [[img layer] setShadowRadius:6];

    [[img layer] setShadowOpacity:1];

    [[img layer] setShadowColor:[UIColor lightGrayColor].CGColor];

//变灰色

-(UIImage*)getGrayImage:(UIImage*)sourceImage

{

    int width = sourceImage.size.width;

    int height = sourceImage.size.height;

    CGColorSpaceRef colorSpace = CGColorSpaceCreateDeviceGray();

    CGContextRef context = CGBitmapContextCreate (nil,width,height,8,0,colorSpace,kCGImageAlphaNone);

    CGColorSpaceRelease(colorSpace);

    

    if (context == NULL) {

        return nil;

    }

    

    CGContextDrawImage(context,CGRectMake(0, 0, width, height), sourceImage.CGImage);

    UIImage *grayImage = [UIImage imageWithCGImage:CGBitmapContextCreateImage(context)];

    CGContextRelease(context);

    

    return grayImage;

}