C#生成缩略图,C#给图片添加水印

生成缩略图

        #region 生成缩略图
        /// <summary>
        /// 生成缩略图
        /// </summary>
        /// <param name="originalImagePath">源图路径（物理路径）</param>
        /// <param name="thumbnailPath">缩略图路径（物理路径）</param>
        /// <param name="width">缩略图宽度</param>
        /// <param name="height">缩略图高度</param>
        /// <param name="mode">生成缩略图的方式</param>    
        public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height, string mode)
        {
            Image originalImage = Image.FromFile(originalImagePath);

            int towidth = width;
            int toheight = height;

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

            switch (mode)
            {
                case "HW"://指定高宽缩放（可能变形）                
                    break;
                case "WC":
                    if (originalImage.Width > width)
                    {
                        toheight = originalImage.Height * width / originalImage.Width;
                    }
                    else
                    {
                        towidth = originalImage.Width;
                        toheight = originalImage.Height;
                    }
                    break;
                case "W"://指定宽，高按比例                    
                    toheight = originalImage.Height * width / originalImage.Width;
                    break;
                case "H"://指定高，宽按比例
                    towidth = originalImage.Width * height / originalImage.Height;
                    break;
                case "Cut"://指定高宽裁减（不变形）                
                    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;
            }

            //新建一个bmp图片
            Image bitmap = new System.Drawing.Bitmap(towidth, toheight);

            //新建一个画板
            Graphics g = System.Drawing.Graphics.FromImage(bitmap);

            //设置高质量插值法
            g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.High;

            //设置高质量,低速度呈现平滑程度
            g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

            //清空画布并以透明背景色填充
            g.Clear(Color.Transparent);

            //在指定位置并且按指定大小绘制原图片的指定部分
            g.DrawImage(originalImage, new Rectangle(0, 0, towidth, toheight),
                new Rectangle(x, y, ow, oh),
                GraphicsUnit.Pixel);

            try
            {
                //以jpg格式保存缩略图
                bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
            catch (System.Exception e)
            {
                throw e;
            }
            finally
            {
                originalImage.Dispose();
                bitmap.Dispose();
                g.Dispose();
            }
        }
        #endregion

在图片上生成图片水印

#region 在图片上生成图片水印
        /// <summary>  
        /// 在图片上生成图片水印
        /// </summary>  
        /// <param name="Path">原服务器图片路径 </param>  
        /// <param name="Path_syp">生成的带图片水印的图片路径 </param>  
        /// <param name="Path_sypf">水印图片路径 </param>  
        public static void AddWaterPic(string Path, string Path_syp, string Path_sypf,string style)
        {
            Path = HttpContext.Current.Server.MapPath(Path);
            Path_syp = HttpContext.Current.Server.MapPath(Path_syp);

            System.Drawing.Image image = System.Drawing.Image.FromFile(Path);
            System.Drawing.Image copyImage = System.Drawing.Image.FromFile(Path_sypf);
            Graphics g = Graphics.FromImage(image);
            int x=0;
            int y=0;

            switch (style)
            {
                case "C":
                    x = image.Width/2 - copyImage.Width/2;
                    y = Convert.ToInt32(image.Height * 0.8) - copyImage.Height/2;
                    break;
                case "RD":
                    x = (image.Width - copyImage.Width) - 20;
                    y = (image.Height - copyImage.Height) - 20;
                    break;
            }

            Rectangle rect = new Rectangle(x, y, copyImage.Width, copyImage.Height);
            g.DrawImage(copyImage, rect, 0, 0, copyImage.Width, copyImage.Height, GraphicsUnit.Pixel);
            g.Dispose();

            image.Save(Path_syp);
            image.Dispose();
        }
        #endregion