关于上传图片生成缩略图的程序

Question

我在网上找到这么一个生成缩略图的程序，生成的缩略图很清晰，容量也很小，但就是宽、高比例失调,代码如下:
/// <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 "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();
            }
        }当生成缩略图的方式mode选择"cut"时,所生成的图片不完整,下面有的都截掉了
选H或者W时所生成缩略图的大小不改变似的，不知大家有没有碰到这样的问题如果有更好的程序拿出来的的话，非常感谢！

Answer 1

给你一个我自用的简洁点的        /// <summary>
        /// by vengair
        /// </summary>
        /// <param name="image"></param>
        /// <param name="percentage"></param>
        /// <returns></returns>
        private static Image GenerateThumbnailImage(Image image, int percentage)
        {
            Bitmap myBitmap = new Bitmap((int)(image.Width * percentage / 100), (int)(image.Height * percentage / 100));
            Graphics myGraphics = Graphics.FromImage(myBitmap);            // 绘制边框和背景
            myGraphics.FillRectangle(Brushes.Gray, new Rectangle(0, 0, myBitmap.Width, myBitmap.Height));
            myGraphics.FillRectangle(Brushes.White, new Rectangle(1, 1, myBitmap.Width - 2, myBitmap.Height - 2));            myGraphics.InterpolationMode = InterpolationMode.HighQualityBicubic;
            myGraphics.SmoothingMode = SmoothingMode.HighQuality;
            myGraphics.DrawImage(image, new Rectangle(2, 2, myBitmap.Width - 4, myBitmap.Height - 4));
            myGraphics.Dispose();            return (Image)myBitmap;
        }

Answer 2

本人从事C#开发已有三年时间，希望结交行内好友，大家共同进取，
请加我的QQ群号码：35651007 注明CSDN即可