MathHelper.cs :  » Bloggers » SubText » Subtext » Framework » Util » C# / CSharp Open Source

#region Disclaimer/Info

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#endregion

using System;
using System.Drawing;

namespace Subtext.Framework.Util{
    public static class MathHelper
    {
        public static decimal GetAspectRatio(this Size size)
        {
            return GetAspectRatio(size.Width, size.Height);
        }

        public static decimal GetAspectRatio(int width, int height)
        {
            return width / height;
        }

        /// <summary>
        /// Returns a new size which would scale the original size to fit 
        /// within the specified maximum size while retaining its aspect 
        /// ratio.
        /// </summary>
        public static Size ScaleToFit(this Size original, int maxWidth, int maxHeight)
        {
            decimal aspectRatio = GetAspectRatio(maxWidth, maxHeight);

            decimal originalWidth = original.Width;
            decimal originalHeight = original.Height;


            if(originalWidth <= maxWidth && originalHeight <= maxHeight)
            {
                return original;
            }

            // determine the largest factor 
            decimal factor;
            if(original.GetAspectRatio() > aspectRatio)
            {
                factor = originalWidth / maxWidth;
            }
            else
            {
                factor = originalHeight / maxHeight;
            }

            int newWidth = Convert.ToInt32(originalWidth / factor);
            int newHeight = Convert.ToInt32(originalHeight / factor);

            return new Size(newWidth, newHeight);
        }

        /// <summary>
        /// Returns a new size which would scale the original size to fit 
        /// within the specified maximum size while retaining its aspect 
        /// ratio.
        /// </summary>
        public static Size ScaleToFit(this Size original, Size maxSize)
        {
            return original.ScaleToFit(maxSize.Width, maxSize.Height);
        }
    }
}