asp.net实现透明图片的输出,图片背景变黑色问题!(C#) 特急!

Question

专家啊,救命啊!
private void DesignImage(string DesFilePath,int DesR,int DesWidth,int DesHeight)
    {
        System.Drawing.Image DesImage = System.Drawing.Image.FromFile(DesFilePath);
        if(DesR==1)
        {
            DesImage.RotateFlip(RotateFlipType.Rotate90FlipY);  //90度旋转
        }
        else if (DesR == 2)
        {
            DesImage.RotateFlip(RotateFlipType.RotateNoneFlipY); //180度旋转
        }
        else if (DesR == 3)
        {
            DesImage.RotateFlip(RotateFlipType.Rotate270FlipY);//360度旋转
        }
        int x = 0;
        int y = 0;
        int w = DesImage.Width;
        int h = DesImage.Height;        //目标位图
        Bitmap dsImage = new Bitmap(DesWidth, DesHeight);
        System.Drawing.Graphics g = System.Drawing.Graphics.FromImage(dsImage);        //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;
        //g.Clear(System.Drawing.Color.Transparent);
        Color color = Color.FromArgb(0, Color.Transparent);   //背景透明
        g.FillRectangle(new SolidBrush(color), new Rectangle(0, 0, DesWidth, DesHeight));
        g.DrawImage(DesImage, new System.Drawing.Rectangle(0, 0, DesWidth, DesHeight), new System.Drawing.Rectangle(x, y, w, h), System.Drawing.GraphicsUnit.Pixel);
        dsImage.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Gif);
        g.Dispose();
    }
以上的代码是我实现透明图片输出的函数内容,可输出的图片的背景不是透明色,而是黑色,调试了很多次,都无法解决,特开此贴,请专家救急啊!

Answer 1

若是有时间请加我的msn:[email protected] ,谢谢.

Answer 2

Color color = Color.FromArgb(0, Color.Transparent);   //背景透明 这里出现问题 我也刚发了个帖子：http://topic.csdn.net/u/20080507/15/9b05cf15-ad71-4722-a53d-8e3946fddd1d.html应该改成
 System.Drawing.Color.FromArgb(255, 250, 255, 249));

Answer 3

Color color = Color.FromArgb(0, Color.White);   //试试啊

Answer 4

g.Clear(System.Drawing.Color.Transparent); 
这句好像是定义背景的吧 怎么注释了

Answer 5

这有代码
http://www.c-sharpcorner.com/UploadFile/jacquesphilip/MakingThumbnailsOfTransparentImages11162005004933AM/MakingThumbnailsOfTransparentImages.aspx
http://www.codedblog.com/2007/08/28/generating-a-transparent-gif-image-using-c/http://support.microsoft.com/kb/319061