View 装换成图片

- (UIImage*) imageWithUIView:(UIView*) view
{
    UIGraphicsBeginImageContext(view.bounds.size);
    CGContextRef ctx = UIGraphicsGetCurrentContext();
    [view.layer renderInContext:ctx];
    UIImage* tImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return tImage;
}