Viewport Origin animation

Question

I am developing a Windows phone app, where I have a viewportcontroller, that enables me to zoom in and out on content. I want to center the zoom at the point where I zoom. Whic

Answer 1

I tried a few different approaches and this one came out to be the smoothest. It's not pretty, but it works.

public partial class MainPage : PhoneApplicationPage
{
    private const int MoveCount = 25;

    private double _tickX;
    private double _tickY;

    private int _adjustCount = MoveCount+1;

    public MainPage()
    {
        InitializeComponent();
        Viewport.ViewportChanged += ViewportOnViewportChanged;
    }

    private void ViewportOnViewportChanged(object sender, ViewportChangedEventArgs viewportChangedEventArgs)
    {
        AdjstViewport();
    }

    private void AdjstViewport()
    {
        if (_adjustCount >= MoveCount) return;
        _adjustCount++;
        Viewport.SetViewportOrigin(new Point(Viewport.Viewport.X + _tickX, Viewport.Viewport.Y + _tickY));                        
    }

    private async void OnButtonClick(object sender, System.Windows.RoutedEventArgs e)
    {
        _adjustCount = 0;

        var content = (FrameworkElement)Viewport.Content;
        double zoomOriginX = (content.ActualWidth / 2) - (Viewport.Viewport.Width / 2);
        double zoomOriginY = (content.ActualHeight / 2) - (Viewport.Viewport.Height / 2);

        double distanceX = zoomOriginX - Viewport.Viewport.X;
        double distanceY = zoomOriginY - Viewport.Viewport.Y;

        _tickX = distanceX / MoveCount;
        _tickY = distanceY / MoveCount;

        AdjstViewport();
    }
}