Avalonia MapGraticule

MapControl/Avalonia/MapGraticule.Avalonia.cs

@@ -0,0 +1,138 @@
+// XAML Map Control - https://github.com/ClemensFischer/XAML-Map-Control
+// Copyright © 2024 Clemens Fischer
+// Licensed under the Microsoft Public License (Ms-PL)
+
+using Avalonia.Controls;
+using Avalonia.Controls.Documents;
+using Avalonia.Controls.Shapes;
+using Avalonia.Media;
+using System.Collections.Generic;
+using System.Globalization;
+using System.Linq;
+
+namespace MapControl
+{
+    public partial class MapGraticule : Control, IMapElement
+    {
+        public static readonly StyledProperty<IBrush> ForegroundProperty =
+            DependencyPropertyHelper.AddOwner<MapGraticule, IBrush>(TextElement.ForegroundProperty, null,
+                (graticule, oldValue, newValue) => graticule.InvalidateVisual());
+
+        public static readonly StyledProperty<FontFamily> FontFamilyProperty =
+            DependencyPropertyHelper.AddOwner<MapGraticule, FontFamily>(TextElement.FontFamilyProperty);
+
+        public static readonly StyledProperty<double> FontSizeProperty =
+            DependencyPropertyHelper.AddOwner<MapGraticule, double>(TextElement.FontSizeProperty);
+
+        public static readonly StyledProperty<double> StrokeThicknessProperty =
+            DependencyPropertyHelper.AddOwner<MapGraticule, double>(Shape.StrokeThicknessProperty, 0.5);
+
+        public IBrush Foreground
+        {
+            get => GetValue(ForegroundProperty);
+            set => SetValue(ForegroundProperty, value);
+        }
+
+        public FontFamily FontFamily
+        {
+            get => GetValue(FontFamilyProperty);
+            set => SetValue(FontFamilyProperty, value);
+        }
+
+        public double FontSize
+        {
+            get => GetValue(FontSizeProperty);
+            set => SetValue(FontSizeProperty, value);
+        }
+
+        public double StrokeThickness
+        {
+            get => GetValue(StrokeThicknessProperty);
+            set => SetValue(StrokeThicknessProperty, value);
+        }
+
+        private MapBase parentMap;
+
+        /// <summary>
+        /// Implements IMapElement.ParentMap.
+        /// </summary>
+        public MapBase ParentMap
+        {
+            get => parentMap;
+            set
+            {
+                if (parentMap != null)
+                {
+                    parentMap.ViewportChanged -= OnViewportChanged;
+                }
+
+                parentMap = value;
+
+                if (parentMap != null)
+                {
+                    parentMap.ViewportChanged += OnViewportChanged;
+                }
+            }
+        }
+
+        private void OnViewportChanged(object sender, ViewportChangedEventArgs e)
+        {
+            InvalidateVisual();
+        }
+
+        public override void Render(DrawingContext drawingContext)
+        {
+            if (parentMap != null)
+            {
+                var pathGeometry = new PathGeometry();
+
+                var labels = DrawGraticule(pathGeometry.Figures);
+
+                var pen = new Pen
+                {
+                    Brush = Foreground,
+                    Thickness = StrokeThickness,
+                };
+
+                drawingContext.DrawGeometry(null, pen, pathGeometry);
+
+                if (labels.Count > 0)
+                {
+                    var typeface = new Typeface(FontFamily, FontStyle.Normal, FontWeight.Normal, FontStretch.Normal);
+
+                    foreach (var label in labels)
+                    {
+                        var latText = new FormattedText(label.LatitudeText,
+                            CultureInfo.InvariantCulture, FlowDirection.LeftToRight, typeface, FontSize, Foreground);
+
+                        var lonText = new FormattedText(label.LongitudeText,
+                            CultureInfo.InvariantCulture, FlowDirection.LeftToRight, typeface, FontSize, Foreground);
+
+                        var x = StrokeThickness / 2d + 2d;
+                        var y1 = -StrokeThickness / 2d - latText.Height;
+                        var y2 = StrokeThickness / 2d;
+
+                        using var pushState = drawingContext.PushTransform(
+                            Matrix.CreateRotation(Matrix.ToRadians(label.Rotation)) *
+                            Matrix.CreateTranslation(label.X, label.Y));
+
+                        drawingContext.DrawText(latText, new Point(x, y1));
+                        drawingContext.DrawText(lonText, new Point(x, y2));
+                    }
+                }
+            }
+        }
+
+        private static PathFigure CreatePolylineFigure(IEnumerable<Point> points)
+        {
+            var figure = new PathFigure
+            {
+                StartPoint = points.First(),
+                IsFilled = false
+            };
+
+            figure.Segments.Add(new PolyLineSegment(points.Skip(1)));
+            return figure;
+        }
+    }
+}