How to resize an image maintaining the aspect ratio in C#

Question

I need to know of a way to resize an image to fit in a box without the image stretching too much. The box has set width and height and I want the image to fill as much of the box as possible but maintain the aspect ratio it originally had.

Answer 1

//calculate the ratio
double dbl = (double)image.Width / (double)image.Height;

//set height of image to boxHeight and check if resulting width is less than boxWidth, 
//else set width of image to boxWidth and calculate new height
if( (int)((double)boxHeight * dbl) <= boxWidth )
{
    resizedImage = new Bitmap(original, (int)((double)boxHeight * dbl), boxHeight);
}
else
{
    resizedImage = new Bitmap(original, boxWidth, (int)((double)boxWidth / dbl) );
}

The formula for scaling with the same ratio is:

newWidth =  (int)((double)boxHeight * dbl)

or

newHeight =  (int)((double)boxWidth / dbl)