iOS 截屏

//方法一:截取（0，0）到(55,100)区域的图片

    UIGraphicsBeginImageContext(CGSizeMake(320,460));

    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage*image=UIGraphicsGetImageFromCurrentImageContext();

    UIGraphicsEndImageContext();

    //然后将该图片保存到图片图

    UIImageWriteToSavedPhotosAlbum(image,nil,nil,nil);

//方法二:截取（100，270）到(120,100)区域的图片

    UIGraphicsBeginImageContext(CGSizeMake(320, 460));

    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];

    UIImage*parentImage=UIGraphicsGetImageFromCurrentImageContext();

    CGImageRef imageRef = parentImage.CGImage;

    CGRect myImageRect=CGRectMake(100, 270, 120, 100);

    CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, myImageRect);

    CGSize size=CGSizeMake(320, 100);

    UIGraphicsBeginImageContext(size);

    CGContextRef context = UIGraphicsGetCurrentContext();

    CGContextDrawImage(context, myImageRect, subImageRef);

    UIImage* image = [UIImage imageWithCGImage:subImageRef];

    UIGraphicsEndImageContext();

    CGImageRelease(imageRef);

    UIGraphicsEndImageContext();

    //然后将该图片保存到图片图

    UIImageWriteToSavedPhotosAlbum(image,nil,nil,nil);

//方法三：截屏，全屏，包括电池栏

UIImage *image = [UIImage imageWithCGImage:UIGetScreenImage()];

    //然后将该图片保存到图片图

    UIImageWriteToSavedPhotosAlbum(image,nil,nil,nil);