XAML-Map-Control/MapControl/Shared/MapBase.cs

// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
// Copyright © 2024 Clemens Fischer
// Licensed under the Microsoft Public License (Ms-PL)

using System;
#if WINUI
using Microsoft.UI.Xaml;
using Microsoft.UI.Xaml.Media.Animation;
#elif UWP
using Windows.UI.Xaml;
using Windows.UI.Xaml.Media.Animation;
#else
using System.Windows;
using System.Windows.Media;
using System.Windows.Media.Animation;
#endif

namespace MapControl
{
    public partial class MapBase
    {
        public static readonly DependencyProperty MinZoomLevelProperty = DependencyProperty.Register(
            nameof(MinZoomLevel), typeof(double), typeof(MapBase),
            new PropertyMetadata(1d, (o, e) => ((MapBase)o).MinZoomLevelPropertyChanged((double)e.NewValue)));

        public static readonly DependencyProperty MaxZoomLevelProperty = DependencyProperty.Register(
            nameof(MaxZoomLevel), typeof(double), typeof(MapBase),
            new PropertyMetadata(20d, (o, e) => ((MapBase)o).MaxZoomLevelPropertyChanged((double)e.NewValue)));

        public static readonly DependencyProperty AnimationEasingFunctionProperty = DependencyProperty.Register(
            nameof(AnimationEasingFunction), typeof(EasingFunctionBase), typeof(MapBase),
            new PropertyMetadata(new QuadraticEase { EasingMode = EasingMode.EaseOut }));

        private PointAnimation centerAnimation;
        private DoubleAnimation zoomLevelAnimation;
        private DoubleAnimation headingAnimation;

        /// <summary>
        /// Gets or sets the EasingFunction of the Center, ZoomLevel and Heading animations.
        /// The default value is a QuadraticEase with EasingMode.EaseOut.
        /// </summary>
        public EasingFunctionBase AnimationEasingFunction
        {
            get => (EasingFunctionBase)GetValue(AnimationEasingFunctionProperty);
            set => SetValue(AnimationEasingFunctionProperty, value);
        }

        /// <summary>
        /// Gets the scaling factor from projected map coordinates to view coordinates,
        /// as pixels per meter.
        /// </summary>
        public double ViewScale => (double)GetValue(ViewScaleProperty);

        /// <summary>
        /// Gets a transform Matrix for scaling and rotating objects that are anchored
        /// at a Location from map coordinates (i.e. meters) to view coordinates.
        /// </summary>
        public Matrix GetMapTransform(Location location)
        {
            var scale = GetScale(location);

            var transform = new Matrix(scale.X, 0d, 0d, scale.Y, 0d, 0d);
            transform.Rotate(ViewTransform.Rotation);

            return transform;
        }

        private void MapProjectionPropertyChanged(MapProjection projection)
        {
            maxLatitude = 90d;

            if (projection.Type <= MapProjectionType.NormalCylindrical)
            {
                var maxLocation = projection.MapToLocation(new Point(0d, 180d * MapProjection.Wgs84MeterPerDegree));

                if (maxLocation != null && maxLocation.Latitude < 90d)
                {
                    maxLatitude = maxLocation.Latitude;

                    CoerceCenterProperty(CenterProperty, Center);
                }
            }

            ResetTransformCenter();
            UpdateTransform(false, true);
        }

        private Location CoerceCenterProperty(DependencyProperty property, Location center)
        {
            var c = center;

            if (center == null)
            {
                center = new Location();
            }
            else if (
                center.Latitude < -maxLatitude || center.Latitude > maxLatitude ||
                center.Longitude < -180d || center.Longitude > 180d)
            {
                center = new Location(
                    Math.Min(Math.Max(center.Latitude, -maxLatitude), maxLatitude),
                    Location.NormalizeLongitude(center.Longitude));
            }

            if (center != c)
            {
                SetValueInternal(property, center);
            }

            return center;
        }

        private void CenterPropertyChanged(Location center)
        {
            if (!internalPropertyChange)
            {
                center = CoerceCenterProperty(CenterProperty, center);

                UpdateTransform();

                if (centerAnimation == null)
                {
                    SetValueInternal(TargetCenterProperty, center);
                }
            }
        }

        private void TargetCenterPropertyChanged(Location targetCenter)
        {
            if (!internalPropertyChange)
            {
                targetCenter = CoerceCenterProperty(TargetCenterProperty, targetCenter);

                if (!targetCenter.Equals(Center))
                {
                    if (centerAnimation != null)
                    {
                        centerAnimation.Completed -= CenterAnimationCompleted;
                    }

                    centerAnimation = new PointAnimation
                    {
                        From = new Point(Center.Longitude, Center.Latitude),
                        To = new Point(ConstrainedLongitude(targetCenter.Longitude), targetCenter.Latitude),
                        Duration = AnimationDuration,
                        EasingFunction = AnimationEasingFunction
                    };

                    centerAnimation.Completed += CenterAnimationCompleted;

                    this.BeginAnimation(CenterPointProperty, centerAnimation);
                }
            }
        }

        private void CenterAnimationCompleted(object sender, object e)
        {
            if (centerAnimation != null)
            {
                centerAnimation.Completed -= CenterAnimationCompleted;
                centerAnimation = null;

                this.BeginAnimation(CenterPointProperty, null);
            }
        }

        private void CenterPointPropertyChanged(Location center)
        {
            if (centerAnimation != null)
            {
                SetValueInternal(CenterProperty, center);
                UpdateTransform();
            }
        }

        private void MinZoomLevelPropertyChanged(double minZoomLevel)
        {
            if (minZoomLevel < 0d || minZoomLevel > MaxZoomLevel)
            {
                minZoomLevel = Math.Min(Math.Max(minZoomLevel, 0d), MaxZoomLevel);

                SetValueInternal(MinZoomLevelProperty, minZoomLevel);
            }

            if (ZoomLevel < minZoomLevel)
            {
                ZoomLevel = minZoomLevel;
            }
        }

        private void MaxZoomLevelPropertyChanged(double maxZoomLevel)
        {
            if (maxZoomLevel < MinZoomLevel)
            {
                maxZoomLevel = MinZoomLevel;

                SetValueInternal(MaxZoomLevelProperty, maxZoomLevel);
            }

            if (ZoomLevel > maxZoomLevel)
            {
                ZoomLevel = maxZoomLevel;
            }
        }

        private double CoerceZoomLevelProperty(DependencyProperty property, double zoomLevel)
        {
            if (zoomLevel < MinZoomLevel || zoomLevel > MaxZoomLevel)
            {
                zoomLevel = Math.Min(Math.Max(zoomLevel, MinZoomLevel), MaxZoomLevel);

                SetValueInternal(property, zoomLevel);
            }

            return zoomLevel;
        }

        private void ZoomLevelPropertyChanged(double zoomLevel)
        {
            if (!internalPropertyChange)
            {
                zoomLevel = CoerceZoomLevelProperty(ZoomLevelProperty, zoomLevel);

                UpdateTransform();

                if (zoomLevelAnimation == null)
                {
                    SetValueInternal(TargetZoomLevelProperty, zoomLevel);
                }
            }
        }

        private void TargetZoomLevelPropertyChanged(double targetZoomLevel)
        {
            if (!internalPropertyChange)
            {
                targetZoomLevel = CoerceZoomLevelProperty(TargetZoomLevelProperty, targetZoomLevel);

                if (targetZoomLevel != ZoomLevel)
                {
                    if (zoomLevelAnimation != null)
                    {
                        zoomLevelAnimation.Completed -= ZoomLevelAnimationCompleted;
                    }

                    zoomLevelAnimation = new DoubleAnimation
                    {
                        To = targetZoomLevel,
                        Duration = AnimationDuration,
                        EasingFunction = AnimationEasingFunction
                    };

                    zoomLevelAnimation.Completed += ZoomLevelAnimationCompleted;

                    this.BeginAnimation(ZoomLevelProperty, zoomLevelAnimation);
                }
            }
        }

        private void ZoomLevelAnimationCompleted(object sender, object e)
        {
            if (zoomLevelAnimation != null)
            {
                SetValueInternal(ZoomLevelProperty, TargetZoomLevel);
                UpdateTransform(true);

                zoomLevelAnimation.Completed -= ZoomLevelAnimationCompleted;
                zoomLevelAnimation = null;

                this.BeginAnimation(ZoomLevelProperty, null);
            }
        }

        private double CoerceHeadingProperty(DependencyProperty property, double heading)
        {
            if (heading < 0d || heading > 360d)
            {
                heading = ((heading % 360d) + 360d) % 360d;

                SetValueInternal(property, heading);
            }

            return heading;
        }

        private void HeadingPropertyChanged(double heading)
        {
            if (!internalPropertyChange)
            {
                heading = CoerceHeadingProperty(HeadingProperty, heading);

                UpdateTransform();

                if (headingAnimation == null)
                {
                    SetValueInternal(TargetHeadingProperty, heading);
                }
            }
        }

        private void TargetHeadingPropertyChanged(double targetHeading)
        {
            if (!internalPropertyChange)
            {
                targetHeading = CoerceHeadingProperty(TargetHeadingProperty, targetHeading);

                if (targetHeading != Heading)
                {
                    var delta = targetHeading - Heading;

                    if (delta > 180d)
                    {
                        delta -= 360d;
                    }
                    else if (delta < -180d)
                    {
                        delta += 360d;
                    }

                    if (headingAnimation != null)
                    {
                        headingAnimation.Completed -= HeadingAnimationCompleted;
                    }

                    headingAnimation = new DoubleAnimation
                    {
                        By = delta,
                        Duration = AnimationDuration,
                        EasingFunction = AnimationEasingFunction
                    };

                    headingAnimation.Completed += HeadingAnimationCompleted;

                    this.BeginAnimation(HeadingProperty, headingAnimation);
                }
            }
        }

        private void HeadingAnimationCompleted(object sender, object e)
        {
            if (headingAnimation != null)
            {
                SetValueInternal(HeadingProperty, TargetHeading);
                UpdateTransform();

                headingAnimation.Completed -= HeadingAnimationCompleted;
                headingAnimation = null;

                this.BeginAnimation(HeadingProperty, null);
            }
        }
    }
}