Silverlight Database Deep Zoom

using System;
using System.Collections.Generic;
using System.Net;
using System.Windows;
using System.Windows.Controls;
using System.Windows.Documents;
using System.Windows.Input;
using System.Windows.Media;
using System.Windows.Media.Animation;
using System.Windows.Shapes;
using DeepZoomSilverlightProject.ImageListClient;

namespace DeepZoomSilverlightProject
{
    public partial class Page : UserControl
    {
        //
        // Based on prior work done by Lutz Gerhard, Peter Blois, and Scott Hanselman
        //

        double zoom = 1;
        bool duringDrag = false;
        bool mouseDown = false;
        Point lastMouseDownPos = new Point();
        Point lastMousePos = new Point();
        Point lastMouseViewPort = new Point();


        public double ZoomFactor
        {
            get { return zoom; }
            set { zoom = value; }
        }

        public Page()
        {
            InitializeComponent();

            // Setting the datasource for the list using the ImageListService
            var imageListClient = ServiceClientFactory.GetImageListServiceClient();
            imageListClient.GetImageListCompleted += new EventHandler<DeepZoomSilverlightProject.ImageListClient.GetImageListCompletedEventArgs>(imageListCliet_GetImageListCompleted);
            imageListClient.GetImageListAsync();

            //
            // Firing an event when the MultiScaleImage is Loaded
            //
            this.msi.Loaded += new RoutedEventHandler(msi_Loaded);

            //
            // Firing an event when all of the images have been Loaded
            //
            this.msi.ImageOpenSucceeded += new RoutedEventHandler(msi_ImageOpenSucceeded);

            //
            // Handling all of the mouse and keyboard functionality
            //
            msi.MouseLeftButtonDown += delegate(object sender, MouseButtonEventArgs e)
            {
                lastMouseDownPos = e.GetPosition(msi);
                lastMouseViewPort = msi.ViewportOrigin;

                mouseDown = true;

                msi.CaptureMouse();
            };

            msi.MouseLeftButtonUp += delegate(object sender, MouseButtonEventArgs e)
            {
                if (!duringDrag)
                {
                    bool shiftDown = (Keyboard.Modifiers & ModifierKeys.Shift) == ModifierKeys.Shift;
                    double newzoom = zoom;

                    if (shiftDown)
                    {
                        newzoom /= 2;
                    }
                    else
                    {
                        newzoom *= 2;
                    }

                    Zoom(newzoom, msi.ElementToLogicalPoint(this.lastMousePos));
                }
                duringDrag = false;
                mouseDown = false;

                msi.ReleaseMouseCapture();
            };

            msi.MouseMove += delegate(object sender, MouseEventArgs e)
            {
                lastMousePos = e.GetPosition(msi);
                if (mouseDown && !duringDrag)
                {
                    duringDrag = true;
                    double w = msi.ViewportWidth;
                    Point o = new Point(msi.ViewportOrigin.X, msi.ViewportOrigin.Y);
                    msi.UseSprings = false;
                    msi.ViewportOrigin = new Point(o.X, o.Y);
                    msi.ViewportWidth = w;
                    zoom = 1/w;
                    msi.UseSprings = true;
                }

                if (duringDrag)
                {
                    Point newPoint = lastMouseViewPort;
                    newPoint.X += (lastMouseDownPos.X - lastMousePos.X) / msi.ActualWidth * msi.ViewportWidth;
                    newPoint.Y += (lastMouseDownPos.Y - lastMousePos.Y) / msi.ActualWidth * msi.ViewportWidth;
                    msi.ViewportOrigin = newPoint;
                }

            };

            new MouseWheelHelper(msi).Moved += delegate(object sender, MouseWheelEventArgs e)
            {
                e.Handled = true;

                double newzoom = zoom;

                if (e.Delta < 0)
                    newzoom /= 1.3;
                else
                    newzoom *= 1.3;

                Zoom(newzoom, msi.ElementToLogicalPoint(this.lastMousePos));
                msi.CaptureMouse();
            };
        }

        /// <summary>
        /// Handles the GetImageListCompleted event of the imageListCliet control.
        /// </summary>
        /// <param name="sender">The source of the event.</param>
        /// <param name="e">The <see cref="DeepZoomSilverlightProject.ImageListClient.GetImageListCompletedEventArgs"/> instance containing the event data.</param>
        void imageListCliet_GetImageListCompleted(object sender, DeepZoomSilverlightProject.ImageListClient.GetImageListCompletedEventArgs e)
        {
            // Set the datasource for the image list control
            imageList.ItemsSource = e.Result;

            if (imageList.Items.Count > 0)
                imageList.SelectedIndex = 0;
        }

        /// <summary>
        /// After the Image is opened, calculate the correct size to display the full image.
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        void msi_ImageOpenSucceeded(object sender, RoutedEventArgs e)
        {
            ImageInfo imageInfo = imageList.SelectedItem as ImageInfo;
            if (imageInfo != null)
            {
                // Calculate the aspect ratios of the multi scale image control and the image to be displayed
                double ar_msi = msi.ActualWidth / msi.ActualHeight;
                double ar_image = (double)imageInfo.Width / imageInfo.Height;
                
                // Reset the zoom factor
                ZoomFactor = 1;

                // if the aspect ratio of the control is larger that that of the image
                // we must zoom out the image, so that the full height is shown
                // else we can zoom to full width of image (ViewportWidth = 1)
                if (ar_msi > ar_image)
                    msi.ViewportWidth = ar_msi / ar_image;
                else
                    msi.ViewportWidth = 1;
                msi.ViewportOrigin = new Point(0, 0);
            }
        }

        void msi_Loaded(object sender, RoutedEventArgs e)
        {
            // Hook up any events you want when the image has successfully been opened
        }

        private void Zoom(double newzoom, Point p)
        {
            if (newzoom < 0.1)
            {
                newzoom = 0.1;
            }

            msi.ZoomAboutLogicalPoint(newzoom / zoom, p.X, p.Y);
            zoom = newzoom;
        }

        private void ZoomInClick(object sender, System.Windows.RoutedEventArgs e)
        {
            Zoom(zoom * 1.3, msi.ElementToLogicalPoint(new Point(.5 * msi.ActualWidth, .5 * msi.ActualHeight)));
        }

        private void ZoomOutClick(object sender, System.Windows.RoutedEventArgs e)
        {
            Zoom(zoom / 1.3, msi.ElementToLogicalPoint(new Point(.5 * msi.ActualWidth, .5 * msi.ActualHeight)));
        }

        private void GoHomeClick(object sender, System.Windows.RoutedEventArgs e)
        {
        	this.msi.ViewportWidth = 1;
			this.msi.ViewportOrigin = new Point(0,0);
            ZoomFactor = 1;
        }

        private void GoFullScreenClick(object sender, System.Windows.RoutedEventArgs e)
        {
        	if (!Application.Current.Host.Content.IsFullScreen) 
			{ 
				Application.Current.Host.Content.IsFullScreen = true; 
			} 
			else 
			{ 
				Application.Current.Host.Content.IsFullScreen = false; 
			} 
        }

        // Handling the VSM states
        private void LeaveMovie(object sender, System.Windows.Input.MouseEventArgs e)
        {
            VisualStateManager.GoToState(this, "FadeOut", true);
        }

        private void EnterMovie(object sender, System.Windows.Input.MouseEventArgs e)
        {
            VisualStateManager.GoToState(this, "FadeIn", true);
        }


        // unused functions that show the inner math of Deep Zoom
        public Rect getImageRect()
        {
            return new Rect(-msi.ViewportOrigin.X / msi.ViewportWidth, -msi.ViewportOrigin.Y / msi.ViewportWidth, 1 / msi.ViewportWidth, 1 / msi.ViewportWidth * msi.AspectRatio);
        }

        public Rect ZoomAboutPoint(Rect img, double zAmount, Point pt)
        {
            return new Rect(pt.X + (img.X - pt.X) / zAmount, pt.Y + (img.Y - pt.Y) / zAmount, img.Width / zAmount, img.Height / zAmount);
        }

        public void LayoutDZI(Rect rect)
        {
            double ar = msi.AspectRatio;
            msi.ViewportWidth = 1 / rect.Width;
            msi.ViewportOrigin = new Point(-rect.Left / rect.Width, -rect.Top / rect.Width);
        }

        /// <summary>
        /// When the user selects another image, init a new DeepZoomTileSource object
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        private void imageList_SelectionChanged(object sender, SelectionChangedEventArgs e)
        {
            ImageInfo imageInfo = imageList.SelectedItem as ImageInfo;

            if (imageInfo != null)
            {
                // Setting the source of the multi scale image
                msi.Source = new DeepZoomTileSource(imageInfo.ImageId, imageInfo.Width, imageInfo.Height, imageInfo.TileSize, imageInfo.Overlap, imageInfo.MimeType);
            }
        }
    }
}