How to: Convert a BitmapSource to an Indexed Pixel Format

This example shows how to convert a BitmapSource to an indexed pixel format.

Example

using System;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Media;
using System.Windows.Media.Imaging;
using System.Collections.Generic;
namespace SDKSample
{
    public partial class FormatConvertedBitmapExample2 : Page
    {
        public FormatConvertedBitmapExample2()
        {

            ///// Create a BitmapImage and set it's DecodePixelWidth to 200. Use  /////
            ///// this BitmapImage as a source for other BitmapSource objects.    /////

            BitmapImage myBitmapImage = new BitmapImage();

            // BitmapSource objects like BitmapImage can only have their properties
            // changed within a BeginInit/EndInit block.
            myBitmapImage.BeginInit();
            myBitmapImage.UriSource = new Uri(@"sampleImages/WaterLilies.jpg",UriKind.Relative);

            // To save significant application memory, set the DecodePixelWidth or  
            // DecodePixelHeight of the BitmapImage value of the image source to the desired 
            // height or width of the rendered image. If you don't do this, the application will 
            // cache the image as though it were rendered as its normal size rather then just 
            // the size that is displayed.
            // Note: In order to preserve aspect ratio, set DecodePixelWidth
            // or DecodePixelHeight but not both.
            myBitmapImage.DecodePixelWidth = 200;
            myBitmapImage.EndInit();

            ////////// Convert the BitmapSource to a new format ////////////
            // Use the BitmapImage created above as the source for a new BitmapSource object
            // which is set to a two color pixel format using the FormatConvertedBitmap BitmapSource.                                               
            // Note: New BitmapSource does not cache. It is always pulled when required.

            FormatConvertedBitmap newFormatedBitmapSource = new FormatConvertedBitmap();

            // BitmapSource objects like FormatConvertedBitmap can only have their properties
            // changed within a BeginInit/EndInit block.
            newFormatedBitmapSource.BeginInit();

            // Use the BitmapSource object defined above as the source for this new 
            // BitmapSource (chain the BitmapSource objects together).
            newFormatedBitmapSource.Source = myBitmapImage;

            // Because the DestinationFormat for the FormatConvertedBitmap will be an
            // indexed pixel format (Indexed1),a DestinationPalette also needs to be specified.
            // Below, create a custom two color palette to be used for the DestinationPalette.
            List<System.Windows.Media.Color> colors = new List<System.Windows.Media.Color>();
            colors.Add(System.Windows.Media.Colors.Red);
            colors.Add(System.Windows.Media.Colors.Blue);
            BitmapPalette myPalette = new BitmapPalette(colors);

            // Set the DestinationPalette property to the custom palette created above.
            newFormatedBitmapSource.DestinationPalette = myPalette;

            // Set the DestinationFormat to the palletized pixel format of Indexed1.
            newFormatedBitmapSource.DestinationFormat = PixelFormats.Indexed1;
            newFormatedBitmapSource.EndInit();

            // Create Image Element
            Image myImage = new Image();
            myImage.Width = 200;
            //set image source
            myImage.Source = newFormatedBitmapSource;

            // Add Image to the UI
            StackPanel myStackPanel = new StackPanel();
            myStackPanel.Children.Add(myImage);
            this.Content = myStackPanel;
        }
    }
}