how to resize an image with unknown size to a specific size without too much of deformation?

I want to get an image from a user and re-size it to a specific size but the problem is : I don't know about the user's image size and I have to re-size 开发者_StackOverflow社区it to a certain size but deformation is burden over here.

how can I solve this problem? is there any algorithm according to that? or is there any source code preferably in .net? best regards.

As far as deformation, you could use a combination of cropping and resizing. Your user would help you with the cropping.

I found this code on Code Project with a simple Google search of .net resize an image

imgPhoto = FixedSize(imgPhotoVert, 300, 300);
imgPhoto.Save(WorkingDirectory + 
    @"\images\imageresize_3.jpg", ImageFormat.Jpeg);
imgPhoto.Dispose();
....
static Image FixedSize(Image imgPhoto, int Width, int Height)
{
    int sourceWidth = imgPhoto.Width;
    int sourceHeight = imgPhoto.Height;
    int sourceX = 0;
    int sourceY = 0;
    int destX = 0;
    int destY = 0; 

    float nPercent = 0;
    float nPercentW = 0;
    float nPercentH = 0;

    nPercentW = ((float)Width/(float)sourceWidth);
    nPercentH = ((float)Height/(float)sourceHeight);
    if(nPercentH < nPercentW)
    {
        nPercent = nPercentH;
        destX = System.Convert.ToInt16((Width - 
                      (sourceWidth * nPercent))/2);
    }
    else
    {
        nPercent = nPercentW;
        destY = System.Convert.ToInt16((Height - 
                      (sourceHeight * nPercent))/2);
    }

    int destWidth  = (int)(sourceWidth * nPercent);
    int destHeight = (int)(sourceHeight * nPercent);

    Bitmap bmPhoto = new Bitmap(Width, Height, 
                      PixelFormat.Format24bppRgb);
    bmPhoto.SetResolution(imgPhoto.HorizontalResolution, 
                     imgPhoto.VerticalResolution);

    Graphics grPhoto = Graphics.FromImage(bmPhoto);
    grPhoto.Clear(Color.Red);
    grPhoto.InterpolationMode = 
            InterpolationMode.HighQualityBicubic;

    grPhoto.DrawImage(imgPhoto, 
        new Rectangle(destX,destY,destWidth,destHeight),
        new Rectangle(sourceX,sourceY,sourceWidth,sourceHeight),
        GraphicsUnit.Pixel);

    grPhoto.Dispose();
    return bmPhoto;
}