XAML-Map-Control/MapControl/WPF/Map.WPF.cs

using System.Windows;
using System.Windows.Input;

namespace MapControl;

public partial class Map
{
    static Map()
    {
        IsManipulationEnabledProperty.OverrideMetadata(typeof(Map), new FrameworkPropertyMetadata(true));
    }

    public static readonly DependencyProperty ManipulationModeProperty =
        DependencyPropertyHelper.Register<Map, ManipulationModes>(nameof(ManipulationMode), ManipulationModes.Translate | ManipulationModes.Scale);

    /// <summary>
    /// Gets or sets a value that specifies how the map control handles manipulations.
    /// </summary>
    public ManipulationModes ManipulationMode
    {
        get => (ManipulationModes)GetValue(ManipulationModeProperty);
        set => SetValue(ManipulationModeProperty, value);
    }

    protected override void OnMouseWheel(MouseWheelEventArgs e)
    {
        base.OnMouseWheel(e);

        // Standard mouse wheel delta value is 120.
        //
        OnMouseWheel(e.GetPosition(this), e.Delta / 120d);
    }

    private Point? mousePosition;

    protected override void OnPreviewMouseLeftButtonDown(MouseButtonEventArgs e)
    {
        base.OnPreviewMouseLeftButtonDown(e);

        if (Keyboard.Modifiers == ModifierKeys.None)
        {
            // Do not call CaptureMouse here because it avoids MapItem selection.
            //
            mousePosition = e.GetPosition(this);
        }
    }

    protected override void OnPreviewMouseLeftButtonUp(MouseButtonEventArgs e)
    {
        base.OnPreviewMouseLeftButtonUp(e);

        if (mousePosition.HasValue)
        {
            mousePosition = null;
            ReleaseMouseCapture();
        }
    }

    protected override void OnMouseMove(MouseEventArgs e)
    {
        base.OnMouseMove(e);

        if (mousePosition.HasValue)
        {
            if (!IsMouseCaptured)
            {
                CaptureMouse();
            }

            var p = e.GetPosition(this);
            TranslateMap(new Point(p.X - mousePosition.Value.X, p.Y - mousePosition.Value.Y));
            mousePosition = p;
        }
    }

    protected override void OnManipulationStarted(ManipulationStartedEventArgs e)
    {
        Manipulation.SetManipulationMode(this, ManipulationMode);

        base.OnManipulationStarted(e);
    }

    protected override void OnManipulationDelta(ManipulationDeltaEventArgs e)
    {
        base.OnManipulationDelta(e);

        TransformMap(e.ManipulationOrigin,
            (Point)e.DeltaManipulation.Translation,
            e.DeltaManipulation.Rotation,
            e.DeltaManipulation.Scale.LengthSquared / 2d);
    }
}