Image Resize in C# - Algorith to determine resize dimensions (height and width)

Question

I need to scale down an image that has a height or width greater than a predefined pixel value.

I wrote some code that takes a look at the original image, checks to

Answer 1

The solution posted by Nathaniel actually fails if the image height is larger than the image width. The following example yields the correct result :

private Size ResizeFit(Size originalSize, Size maxSize)
{
    var widthRatio = (double)maxSize.Width / (double)originalSize.Width;
    var heightRatio = (double) maxSize.Height/(double) originalSize.Height;
    var minAspectRatio = Math.Min(widthRatio, heightRatio);
    if (minAspectRatio > 1)
        return originalSize;
    return new Size((int)(originalSize.Width*minAspectRatio), (int)(originalSize.Height*minAspectRatio));
}