截取部分视图作为图片，保存图片到相册

-(UIImage *)getResultImageFrom:(UIImageView *)imageView {    UIGraphicsBeginImageContext(CGSizeMake(imageView.bounds.size.width , imageView.bounds.size.height ));    [imageView.layer renderInContext:UIGraphicsGetCurrentContext()];    UIImage *result =UIGraphicsGetImageFromCurrentImageContext();    UIGraphicsEndImageContext();       return result;}

 UIImageWriteToSavedPhotosAlbum(resultImg, self, @selector(image:didFinishSavingWithError:contextInfo:), NULL);