Canvas保存为图片

    public static void GenerateCanvas(string imgSaveName, int canvasWidth, int canvasHeight, string imgData)
        {
            try
            {
                if (string.IsNullOrEmpty(imgData)) return;
                if (imgData.StartsWith("data:image/png;base64") == false) return;
                var base64 = imgData.Substring(22);
                byte[] bytes = Convert.FromBase64String(base64);
                MemoryStream memStream = new MemoryStream(bytes);
                BinaryFormatter binFormatter = new BinaryFormatter();
                var img = System.Drawing.Image.FromStream(memStream);
                img.Save(imgSaveName);
            }
            catch (Exception ex)
            {

            }

        }