Added MetricGrid

MapControl/Shared/MapGrid.cs

@@ -0,0 +1,101 @@
+using System.Collections.Generic;
+using System.Linq;
+#if WPF
+using System.Windows;
+using System.Windows.Media;
+#elif UWP
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Media;
+#elif WINUI
+using Microsoft.UI.Xaml;
+using Microsoft.UI.Xaml.Media;
+#elif AVALONIA
+using Avalonia;
+using Avalonia.Media;
+using Brush = Avalonia.Media.IBrush;
+using PathFigureCollection = Avalonia.Media.PathFigures;
+#endif
+
+namespace MapControl
+{
+    /// <summary>
+    /// Base class of map grid or graticule overlays.
+    /// </summary>
+    public abstract partial class MapGrid
+    {
+        protected class Label(string text, double x, double y, double rotation)
+        {
+            public string Text => text;
+            public double X => x;
+            public double Y => y;
+            public double Rotation => rotation;
+        }
+
+        public static readonly DependencyProperty MinLineDistanceProperty =
+            DependencyPropertyHelper.Register<MapGrid, double>(nameof(MinLineDistance), 150d);
+
+        public static readonly DependencyProperty StrokeThicknessProperty =
+            DependencyPropertyHelper.Register<MapGrid, double>(nameof(StrokeThickness), 0.5);
+
+        /// <summary>
+        /// Minimum graticule line distance in pixels. The default value is 150.
+        /// </summary>
+        public double MinLineDistance
+        {
+            get => (double)GetValue(MinLineDistanceProperty);
+            set => SetValue(MinLineDistanceProperty, value);
+        }
+
+        public double StrokeThickness
+        {
+            get => (double)GetValue(StrokeThicknessProperty);
+            set => SetValue(StrokeThicknessProperty, value);
+        }
+
+        public Brush Foreground
+        {
+            get => (Brush)GetValue(ForegroundProperty);
+            set => SetValue(ForegroundProperty, value);
+        }
+
+        public FontFamily FontFamily
+        {
+            get => (FontFamily)GetValue(FontFamilyProperty);
+            set => SetValue(FontFamilyProperty, value);
+        }
+
+        public double FontSize
+        {
+            get => (double)GetValue(FontSizeProperty);
+            set => SetValue(FontSizeProperty, value);
+        }
+
+        protected abstract void DrawGrid(PathFigureCollection figures, List<Label> labels);
+
+        protected static PathFigure CreateLineFigure(Point p1, Point p2)
+        {
+            var figure = new PathFigure
+            {
+                StartPoint = p1,
+                IsClosed = false,
+                IsFilled = false
+            };
+
+            figure.Segments.Add(new LineSegment { Point = p2 });
+            return figure;
+        }
+
+        protected static PathFigure CreatePolylineFigure(IEnumerable<Point> points)
+        {
+            var figure = new PathFigure
+            {
+                StartPoint = points.First(),
+                IsClosed = false,
+                IsFilled = false
+            };
+
+            figure.Segments.Add(CreatePolyLineSegment(points.Skip(1)));
+            return figure;
+        }
+    }
+}