From e0cbfc3a2df49d572714fd5f05c63ecddd975661 Mon Sep 17 00:00:00 2001
From: Steven Kirk <grokys@gmail.com>
Date: Sat, 11 Apr 2015 14:57:34 +0100
Subject: [PATCH] Added support for dashed pens.

---
 Perspex.Controls/Shapes/Shape.cs              | 22 ++++++++++++++++++-
 Perspex.SceneGraph/Media/Pen.cs               | 19 ++++++++++++----
 .../Perspex.Direct2D1/Media/DrawingContext.cs | 15 ++++++++++---
 .../Perspex.Direct2D1/PrimitiveExtensions.cs  | 18 +++++++++++++++
 4 files changed, 66 insertions(+), 8 deletions(-)

diff --git a/Perspex.Controls/Shapes/Shape.cs b/Perspex.Controls/Shapes/Shape.cs
index 8125473cc2..3f296c6b00 100644
--- a/Perspex.Controls/Shapes/Shape.cs
+++ b/Perspex.Controls/Shapes/Shape.cs
@@ -7,6 +7,7 @@
 namespace Perspex.Controls.Shapes
 {
     using System;
+    using Perspex.Collections;
     using Perspex.Controls;
     using Perspex.Media;
 
@@ -21,6 +22,9 @@ namespace Perspex.Controls.Shapes
         public static readonly PerspexProperty<Brush> StrokeProperty =
             PerspexProperty.Register<Shape, Brush>("Stroke");
 
+        public static readonly PerspexProperty<PerspexList<double>> StrokeDashArrayProperty =
+            PerspexProperty.Register<Shape, PerspexList<double>>("StrokeDashArray");
+
         public static readonly PerspexProperty<double> StrokeThicknessProperty =
             PerspexProperty.Register<Shape, double>("StrokeThickness");
 
@@ -28,6 +32,15 @@ namespace Perspex.Controls.Shapes
 
         private Geometry renderedGeometry;
 
+        static Shape()
+        {
+            Control.AffectsRender(FillProperty);
+            Control.AffectsMeasure(StretchProperty);
+            Control.AffectsRender(StrokeProperty);
+            Control.AffectsRender(StrokeDashArrayProperty);
+            Control.AffectsMeasure(StrokeThicknessProperty);
+        }
+
         public abstract Geometry DefiningGeometry
         {
             get;
@@ -68,6 +81,12 @@ namespace Perspex.Controls.Shapes
             set { this.SetValue(StrokeProperty, value); }
         }
 
+        public PerspexList<double> StrokeDashArray
+        {
+            get { return this.GetValue(StrokeDashArrayProperty); }
+            set { this.SetValue(StrokeDashArrayProperty, value); }
+        }
+
         public double StrokeThickness
         {
             get { return this.GetValue(StrokeThicknessProperty); }
@@ -80,7 +99,8 @@ namespace Perspex.Controls.Shapes
 
             if (geometry != null)
             {
-                context.DrawGeometry(this.Fill, new Pen(this.Stroke, this.StrokeThickness), geometry);
+                var pen = new Pen(this.Stroke, this.StrokeThickness, this.StrokeDashArray);
+                context.DrawGeometry(this.Fill, pen, geometry);
             }
         }
 
diff --git a/Perspex.SceneGraph/Media/Pen.cs b/Perspex.SceneGraph/Media/Pen.cs
index 5e73c40334..46b46185d2 100644
--- a/Perspex.SceneGraph/Media/Pen.cs
+++ b/Perspex.SceneGraph/Media/Pen.cs
@@ -6,6 +6,8 @@
 
 namespace Perspex.Media
 {
+    using System.Collections.Generic;
+
     /// <summary>
     /// Describes how a stroke is drawn.
     /// </summary>
@@ -16,10 +18,12 @@ namespace Perspex.Media
         /// </summary>
         /// <param name="brush">The brush used to draw.</param>
         /// <param name="thickness">The stroke thickness.</param>
-        public Pen(Brush brush, double thickness)
+        /// <param name="dashArray">The length of alternating dashes and gaps.</param>
+        public Pen(Brush brush, double thickness, IReadOnlyList<double> dashArray = null)
         {
             this.Brush = brush;
             this.Thickness = thickness;
+            this.DashArray = dashArray;
         }
 
         /// <summary>
@@ -27,20 +31,27 @@ namespace Perspex.Media
         /// </summary>
         /// <param name="color">The stroke color.</param>
         /// <param name="thickness">The stroke thickness.</param>
-        public Pen(uint color, double thickness)
+        /// <param name="dashArray">The length of alternating dashes and gaps.</param>
+        public Pen(uint color, double thickness, IReadOnlyList<double> dashArray = null)
         {
             this.Brush = new SolidColorBrush(color);
             this.Thickness = thickness;
+            this.DashArray = dashArray;
         }
 
         /// <summary>
         /// Gets the brush used to draw the stroke.
         /// </summary>
-        public Brush Brush { get; private set; }
+        public Brush Brush { get; }
+
+        /// <summary>
+        /// Gets the length of alternating dashes and gaps.
+        /// </summary>
+        public IReadOnlyList<double> DashArray { get; }
 
         /// <summary>
         /// Gets the stroke thickness.
         /// </summary>
-        public double Thickness { get; private set; }
+        public double Thickness { get; }
     }
 }
diff --git a/Windows/Perspex.Direct2D1/Media/DrawingContext.cs b/Windows/Perspex.Direct2D1/Media/DrawingContext.cs
index 2279dc6cd2..bbbc81266c 100644
--- a/Windows/Perspex.Direct2D1/Media/DrawingContext.cs
+++ b/Windows/Perspex.Direct2D1/Media/DrawingContext.cs
@@ -80,8 +80,14 @@ namespace Perspex.Direct2D1.Media
             if (pen != null)
             {
                 using (var d2dBrush = pen.Brush.ToDirect2D(this.renderTarget))
+                using (var d2dStroke = pen.ToDirect2DStrokeStyle(this.renderTarget))
                 {
-                    this.renderTarget.DrawLine(p1.ToSharpDX(), p2.ToSharpDX(), d2dBrush);
+                    this.renderTarget.DrawLine(
+                        p1.ToSharpDX(),
+                        p2.ToSharpDX(),
+                        d2dBrush,
+                        (float)pen.Thickness,
+                        d2dStroke);
                 }
             }
         }
@@ -106,9 +112,10 @@ namespace Perspex.Direct2D1.Media
             if (pen != null)
             {
                 using (var d2dBrush = pen.Brush.ToDirect2D(this.renderTarget))
+                using (var d2dStroke = pen.ToDirect2DStrokeStyle(this.renderTarget))
                 {
                     GeometryImpl impl = (GeometryImpl)geometry.PlatformImpl;
-                    this.renderTarget.DrawGeometry(impl.Geometry, d2dBrush, (float)pen.Thickness);
+                    this.renderTarget.DrawGeometry(impl.Geometry, d2dBrush, (float)pen.Thickness, d2dStroke);
                 }
             }
         }
@@ -121,11 +128,13 @@ namespace Perspex.Direct2D1.Media
         public void DrawRectange(Pen pen, Rect rect)
         {
             using (var brush = pen.Brush.ToDirect2D(this.renderTarget))
+            using (var d2dStroke = pen.ToDirect2DStrokeStyle(this.renderTarget))
             {
                 this.renderTarget.DrawRectangle(
                     rect.ToDirect2D(),
                     brush,
-                    (float)pen.Thickness);
+                    (float)pen.Thickness,
+                    d2dStroke);
             }
         }
 
diff --git a/Windows/Perspex.Direct2D1/PrimitiveExtensions.cs b/Windows/Perspex.Direct2D1/PrimitiveExtensions.cs
index 997cd51f0a..b7e43b6fe0 100644
--- a/Windows/Perspex.Direct2D1/PrimitiveExtensions.cs
+++ b/Windows/Perspex.Direct2D1/PrimitiveExtensions.cs
@@ -6,6 +6,7 @@
 
 namespace Perspex.Direct2D1
 {
+    using System.Linq;
     using SharpDX;
     using SharpDX.Direct2D1;
 
@@ -51,6 +52,23 @@ namespace Perspex.Direct2D1
             }
         }
 
+        public static StrokeStyle ToDirect2DStrokeStyle(this Perspex.Media.Pen pen, RenderTarget target)
+        {
+            if (pen.DashArray != null && pen.DashArray.Count > 0)
+            {
+                var properties = new StrokeStyleProperties
+                {
+                    DashStyle = DashStyle.Custom,
+                };
+
+                return new StrokeStyle(target.Factory, properties, pen.DashArray.Select(x => (float)x).ToArray());
+            }
+            else
+            {
+                return null;
+            }
+        }
+
         /// <summary>
         /// Converts a Perspex <see cref="Perspex.Media.Color"/> to Direct2D.
         /// </summary>