Asp.net 函數_上傳圖片,加水印,圖片剪切

 
    ///  <summary>
    /// 生成縮略圖
    ///  </summary>
    ///  <param name="originalImagePath">源圖路徑（物理路徑） </param>
    ///  <param name="thumbnailPath">縮略圖路徑（物理路徑） </param>
    ///  <param name="width">縮略圖寬度 </param>
    ///  <param name="height">縮略圖高度 </param>
    ///  <param name="mode">生成縮略圖的方式 </param>    
    public void MakeThumbnail(string originalImagePath,string logo, string thumbnailPath, int width, int height, string mode,int water)
    {
        System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);
        System.Drawing.Image logoimg = System.Drawing.Image.FromFile(logo);
        int towidth = width;
        int toheight = height;

        int x = 0;
        int y = 0;
        int ow = originalImage.Width;
        int oh = originalImage.Height;

        switch (mode)
        {
            case "HW"://指定高寬縮放（可能變形）                
                break;
            case "W"://指定寬，高按比例                    
                toheight = originalImage.Height * width / originalImage.Width;
                break;
            case "H"://指定高，寬按比例
                towidth = originalImage.Width * height / originalImage.Height;
                break;
            case "Cut"://指定高寬裁減（不變形）                
                if ((double)originalImage.Width / (double)originalImage.Height > (double)towidth / (double)toheight)
                {
                    oh = originalImage.Height;
                    ow = originalImage.Height * towidth / toheight;
                    y = 0;
                    x = (originalImage.Width - ow) / 2;
                }
                else
                {
                    ow = originalImage.Width;
                    oh = originalImage.Width * height / towidth;
                    x = 0;
                    y = (originalImage.Height - oh) / 2;
                }
                break;
            default:
                break;
        }

        //新建一個bmp圖片
        System.Drawing.Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

        //新建一個畫板
        Graphics g = System.Drawing.Graphics.FromImage(bitmap);

        //設置高質量插值法
        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

        //設置高質量,低速度呈現平滑程度
        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

        //清空畫布並以透明背景色填充
        g.Clear(Color.Transparent);

        //在指定位置並且按指定大小繪製原圖片的指定部分
        g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
            new Rectangle(x, y, ow, oh),
            GraphicsUnit.Pixel);
        if (water == 1)
        {
            g.DrawImage(logoimg, new Rectangle(0, 0, logoimg.Width, logoimg.Height),
                new Rectangle(0, 0, 150, 60),
                GraphicsUnit.Pixel);
        }
        //g.DrawString("文字水印", new Font("黑體", 18), new SolidBrush(Color.FromArgb(128, 0, 0, 255)), 10, 10);
        //g.DrawString("文字水印", new Font("黑體", 18), new SolidBrush(Color.White), 9, 9);
        //g.DrawString(" www.soletgo.cn", new Font("Arial", 9), new SolidBrush(Color.Black), 10, 30);
        //g.DrawString(" www.soletgo.cn", new Font("Arial", 9), new SolidBrush(Color.White), 9, 29);

        try
        {
            //以jpg格式保存縮略圖
            bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            bitmap.Dispose();
            g.Dispose();
            logoimg.Dispose();
        }
        catch (System.Exception e)
        {
            throw e;
        }
        finally
        {
            originalImage.Dispose();
            bitmap.Dispose();
            g.Dispose();
        }
    }