using System.IO;
using System.Drawing;
using System;
namespace ImageHelper
{
    public class Resizer
    {
        public static Bitmap GetResizedImage(Stream inputStream, int maxWidth, int maxHeight)
        {
            float tempDimension;
            float newWidth;
            float newHeight;
            try
            {
                Image originalImg = Image.FromStream(inputStream);
                //  work out the width/height for the thumbnail. Preserve aspect ratio and honor max width/height
                //  Note: if the original is smaller than the thumbnail size it will be scaled up
                if (((originalImg.Width / maxWidth)
                            > (originalImg.Width / maxHeight)))
                {
                    tempDimension = originalImg.Width;
                    newWidth = maxWidth;
                    newHeight = (originalImg.Height
                                * (maxWidth / tempDimension));
                    if ((newHeight > maxHeight))
                    {
                        newWidth = (newWidth
                                    * (maxHeight / newHeight));
                        newHeight = maxHeight;
                    }
                }
                else
                {
                    tempDimension = originalImg.Height;
                    newHeight = maxHeight;
                    newWidth = (originalImg.Width
                                * (maxWidth / tempDimension));
                    if ((newWidth > maxWidth))
                    {
                        newHeight = (newHeight
                                    * (maxWidth / newWidth));
                        newWidth = maxWidth;
                    }
                }
                Bitmap resizedImage = new Bitmap(Convert.ToInt32(newWidth), Convert.ToInt32(newHeight));
                // Create a graphics object
                Graphics graphics = Graphics.FromImage(resizedImage);
                //  just in case it's a transparent GIF force the bg to white
                Brush brush = new SolidBrush(System.Drawing.Color.White);
                graphics.FillRectangle(brush, 0, 0, resizedImage.Width, resizedImage.Height);
                // Re-draw the image to the specified height and width
                graphics.DrawImage(originalImg, 0, 0, resizedImage.Width, resizedImage.Height);
                return resizedImage;
            }
            catch
            {
                throw new Exception("Could not process image");
            }


        }
    }
}