PictureBox.cs

// AForge Controls Library
// AForge.NET framework
// http://www.aforgenet.com/framework/
//
// Copyright © AForge.NET, 2005-2011
// contacts@aforgenet.com
//

using System;
using System.Drawing;
using System.Drawing.Imaging;

namespace AForge.Controls
{
    /// <summary>
    /// Picture box control for displaying an image.
    /// </summary>
    /// 
    /// <remarks><para>This control is inherited from System.Windows.Forms.PictureBox and is
    /// aimed to resolve one of its issues - inability to display images with high color depth,
    /// like 16 bpp grayscale, 48 bpp and 64 bpp color images. .NET framework does not handle
    /// 16 bpp grayscale images at all, throwing exception when user tries to display them. Color
    /// images with 48 bpp and 64 bpp are "kind of" supported, but only maximum of 13 bits for each
    /// color plane are allowed. Therefore this control is created, which allows to display as
    /// 16 bpp grayscale images, as 48 bpp and 64 bpp color images.</para>
    /// 
    /// <para><note>To display high color depth images, the control does internal conversion of them
    /// to lower color depth images - 8 bpp grayscale, 24 bpp and 32 bpp color images respectively. In
    /// the case source image already has low color depth, it is displayed without any conversions.
    /// </note></para>
    /// </remarks>
    /// 
    public class PictureBox : System.Windows.Forms.PictureBox
    {
        private Image sourceImage = null;
        private Image convertedImage = null;

        /// <summary>
        /// Gets or sets the image that the PictureBox displays.
        /// </summary>
        /// 
        /// <remarks><para>The property is used to set image to be displayed or to get currently
        /// displayed image.</para>
        /// 
        /// <para><note>In the case if source image has high color depth, like 16 bpp grayscale image,
        /// 48 bpp or 64 bpp color image, it is converted to lower color depth before displaying -
        /// to 8 bpp grayscale, 24 bpp or 32 bpp color image respectively.</note></para>
        /// 
        /// <para><note>During color conversion the original source image is kept unmodified, but internal
        /// converted copy is created. The property always returns original source image.</note></para>
        /// </remarks>
        /// 
        public new Image Image
        {
            get { return sourceImage; }
            set
            {
                // check source image format
                if (
                    ( value != null ) && ( value is Bitmap ) &&
                    ( ( value.PixelFormat == PixelFormat.Format16bppGrayScale ) ||
                      ( value.PixelFormat == PixelFormat.Format48bppRgb) || 
                      ( value.PixelFormat == PixelFormat.Format64bppArgb ) ) )
                {   
                    // convert and display image
                    Image tempImage = AForge.Imaging.Image.Convert16bppTo8bpp( (Bitmap) value );
                    base.Image = tempImage;

                    // dispose previous image if required
                    if ( convertedImage != null )
                    {
                        convertedImage.Dispose( );
                    }

                    convertedImage = tempImage;
                }
                else
                {
                    // display source image as it is
                    base.Image = value;
                }
                sourceImage = value;
            }
        }


    }
}