生成缩略图gif问题在线等

wpfonline 2009-12-14 03:02:42

有一张会动的gif图片　生成缩略图后为什么　图片不会动了呢
下面是生成缩略图代码



 public static void MakeThumbnail(string originalImagePath, string thumbnailPath, int width, int height)

    {

        //获取原始图片  

        System.Drawing.Image originalImage = System.Drawing.Image.FromFile(originalImagePath);

        //缩略图画布宽高  

        int towidth = width;

        int toheight = height;

        //原始图片写入画布坐标和宽高(用来设置裁减溢出部分)  

        int x = 0;

        int y = 0;

        int ow = originalImage.Width;

        int oh = originalImage.Height;

        //原始图片画布,设置写入缩略图画布坐标和宽高(用来原始图片整体宽高缩放)  

        int bg_x = 0;

        int bg_y = 0;

        int bg_w = towidth;

        int bg_h = toheight;

        //倍数变量  

        double multiple = 0;

        //获取宽长的或是高长与缩略图的倍数  

        if (originalImage.Width >= originalImage.Height)

            multiple = (double)originalImage.Width / (double)width;

        else

            multiple = (double)originalImage.Height / (double)height;

        //上传的图片的宽和高小等于缩略图  

        if (ow <= width && oh <= height)

        {

            //缩略图按原始宽高  

            bg_w = originalImage.Width;

            bg_h = originalImage.Height;

            //空白部分用背景色填充  

            //bg_x = Convert.ToInt32(((double)towidth - (double)ow) / 2);

            //bg_y = Convert.ToInt32(((double)toheight - (double)oh) / 2);

        }

        //上传的图片的宽和高大于缩略图  

        else

        {

            //宽高按比例缩放  

            bg_w = Convert.ToInt32((double)originalImage.Width / multiple);

            bg_h = Convert.ToInt32((double)originalImage.Height / multiple);

            //空白部分用背景色填充  

            bg_y = Convert.ToInt32(((double)height - (double)bg_h) / 2);

            bg_x = Convert.ToInt32(((double)width - (double)bg_w) / 2);

        }

        //新建一个bmp图片,并设置缩略图大小.  

        System.Drawing.Image bitmap = new System.Drawing.Bitmap(bg_w, bg_h,PixelFormat.Format24bppRgb);

        //新建一个画板  

        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(bitmap);

        //设置高质量插值法  

        g.InterpolationMode = System.Drawing.Drawing2D.InterpolationMode.HighQualityBilinear;

        //设置高质量,低速度呈现平滑程度  

        g.SmoothingMode = System.Drawing.Drawing2D.SmoothingMode.HighQuality;

        //清空画布并设置背景色  

        g.Clear(System.Drawing.ColorTranslator.FromHtml("#F2F2F2"));

        //在指定位置并且按指定大小绘制原图片的指定部分  

        //第一个System.Drawing.Rectangle是原图片的画布坐标和宽高,第二个是原图片写在画布上的坐标和宽高,最后一个参数是指定数值单位为像素  

        g.DrawImage(originalImage, new System.Drawing.Rectangle(bg_x, bg_y, bg_w, bg_h), new System.Drawing.Rectangle(x, y, ow, oh), System.Drawing.GraphicsUnit.Pixel);

        try

        {

            //获取图片类型  

            string fileExtension = System.IO.Path.GetExtension(originalImagePath).ToLower();

            //按原图片类型保存缩略图片,不按原格式图片会出现模糊,锯齿等问题.  

            switch (fileExtension)

            {

                case ".gif": bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Gif); break;

                case ".jpg": bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Jpeg); break;

                case ".bmp": bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Bmp); break;

                case ".png": bitmap.Save(thumbnailPath, System.Drawing.Imaging.ImageFormat.Png); break;

            }

        }

        catch (System.Exception e)

        {

            throw e;

        }

        finally

        {

            originalImage.Dispose();

            bitmap.Dispose();

            g.Dispose();

        }

    }