C# 递归缩小图片

需求:图片太大,上传到服务器会非常占用服务器空间,而系统又不要求高清图片,于是就通过递归的方式让图片每次减少10%的大小,当图片大小小于100k的时候就保存在本地,核心代码如下:

class Program
{
    static void Main(string[] args)
    {
        byte[] bs = File.ReadAllBytes(@"F:DSCN0361.JPG");
        Image img = zipImage(bs);
        //写入本地
        img.Save("DSCN0361.JPG");
        Console.WriteLine("转换成功");
        Console.Read();
    }

    /// <summary>
    /// 递归缩小图片,每次缩小到90%大小,当图片大小小于100k时就跳出循环,返回Image对象
    /// </summary>
    /// <param name="bs"></param>
    /// <returns></returns>
    static Image zipImage(byte[] bs)
    {
        //最大100k
        if (bs.Length > 1024 * 100)
        {
            Image img = Image.FromStream(new MemoryStream(bs));
            Bitmap b = new Bitmap((int)(img.Width * 0.9), (int)(img.Height * 0.9));
            b.SetResolution(300, 300);
            Graphics g = Graphics.FromImage(b);
            g.InterpolationMode = InterpolationMode.HighQualityBicubic;
            Rectangle recTo = new Rectangle(0, 0, b.Width, b.Height);//表示目标大小
            Rectangle recFrom = new Rectangle(0, 0, img.Width, img.Height);//表示源文件大小
            g.DrawImage(img, recTo, recFrom, GraphicsUnit.Pixel);
            g.Dispose();

            MemoryStream ms = new MemoryStream();
            b.Save(ms, ImageFormat.Jpeg);
            return zipImage(ms.GetBuffer());
        }
        else
        {
            return Image.FromStream(new MemoryStream(bs));
        }

    }
}

 重点是方法 zipImage

原文地址:https://www.cnblogs.com/duanjt/p/7285371.html