c#调整图片分辨率的实现示例

 //这里是拿取redis的数据，并将他它转成图片
public void UpdateBaiduMap()
        {
            if (client.ContainsKey("map_theroad"))
            {
                try
                {
                    string img = client.Get<string>("map_theroad");

                    img = img.Replace("data:image/png;base64,", "").Replace("data:image/jgp;base64,", "").Replace("data:image/jpg;base64,", "").Replace("data:image/jpeg;base64,", "").Replace("{", "").Replace("}", ""); ;//将base64头部信息替换
                    byte[] bytes = Convert.FromBase64String(img);
                    //本来准备
                    //直接将bytes[]发送给led的，后面发现不行
                    MemoryStream memStream = new MemoryStream(bytes);
                    System.Drawing.Image mImage = System.Drawing.Image.FromStream(memStream);
                    Bitmap bp = new Bitmap(mImage);
                    string ImageFilePath = "../../LED/images";
                    if (System.IO.Directory.Exists("../../LED/images") == false)//如果不存在就创建文件夹
                    {
                        System.IO.Directory.CreateDirectory(ImageFilePath);
                    }
                    string ImagePath = ImageFilePath + "/baidu_maps.png";//定义图片名称
                                                                         //需要调整图片分辨率
                    bp = KiResizeImage(bp, 170, 156);
                    bp.Save(ImagePath, System.Drawing.Imaging.ImageFormat.Png);//注意保存路径
                }
                catch (Exception e)
                {

                }
            }
        }

 public Bitmap KiResizeImage(Bitmap bmp, int newW, int newH)
        {
            try
            {
                Bitmap b = new Bitmap(newW, newH);
                Graphics g = Graphics.FromImage(b);
                // 插值算法的质量
                g.InterpolationMode = InterpolationMode.HighQualityBicubic;
                g.DrawImage(bmp, new Rectangle(0, 0, newW, newH), new Rectangle(0, 0, bmp.Width, bmp.Height), GraphicsUnit.Pixel);
                g.Dispose();
                return b;
            }
            catch
            {
                return null;
            }
        }