重写ImageView从相册绘制图片

- (UIImage *)scaleToSize:(CGSize)size {

    //开启图片上下文

    UIGraphicsBeginImageContext(size);

    

    [self drawInRect:CGRectMake(0, 0, size.width, size.height)];

    

    UIImage *endImage = UIGraphicsGetImageFromCurrentImageContext();

    

    UIGraphicsEndImageContext();

    

    return endImage;

}