直接呼叫就可以了

- (UIImage *)scaleImage:(UIImage *)image toScale:(float)scaleSize
{
        UIGraphicsBeginImageContext(CGSizeMake(image.size.width * scaleSize, image.size.height * scaleSize));

       
 [image drawInRect:CGRectMake(0, 0, image.size.width * scaleSize, image.size.height * scaleSize)];


        UIImage *scaledImage = UIGraphicsGetImageFromCurrentImageContext();


        UIGraphicsEndImageContext();
        return scaledImage;
}