IOS对view进行截屏

+(UIImage*)getImageFromView:(UIView *)view{            CGSize s = view.bounds.size;    // 下面方法，第一个参数表示区域大小。第二个参数表示是否是非透明的。如果需要显示半透明效果，需要传NO，否则传YES。第三个参数就是屏幕密度了，关键就是第三个参数。    UIGraphicsBeginImageContextWithOptions(s, NO, [UIScreen mainScreen].scale);    [view.layer renderInContext:UIGraphicsGetCurrentContext()];    UIImage*image = UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();        CGImageRef cgRef = image.CGImage;    CGImageRef imageRef = CGImageCreateWithImageInRect(cgRef,CGRectMake(0,0,view.frame.size.width * [UIScreen mainScreen].scale, view.frame.size.height * [UIScreen mainScreen].scale));    UIImage *thumbScale = [UIImage imageWithCGImage:imageRef];    CGImageRelease(imageRef);    image = thumbScale;    return image;    }