improved pie label positioning

Core/Core.csproj

@@ -134,6 +134,7 @@
     <Compile Include="LogarithmicAxisCore.cs" />
     <Compile Include="Maps\MapData.cs" />
     <Compile Include="PanningOptions.cs" />
+    <Compile Include="PieLabelPosition.cs" />
     <Compile Include="PointTracker.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ScrollMode.cs" />

Core/PieLabelPosition.cs

@@ -0,0 +1,39 @@
+//The MIT License(MIT)
+
+//copyright(c) 2016 Alberto Rodriguez
+
+//Permission is hereby granted, free of charge, to any person obtaining a copy
+//of this software and associated documentation files (the "Software"), to deal
+//in the Software without restriction, including without limitation the rights
+//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//copies of the Software, and to permit persons to whom the Software is
+//furnished to do so, subject to the following conditions:
+
+//The above copyright notice and this permission notice shall be included in all
+//copies or substantial portions of the Software.
+
+//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//SOFTWARE.
+
+namespace LiveCharts
+{
+    /// <summary>
+    /// Describes where a label should be placed
+    /// </summary>
+    public enum PieLabelPosition
+    {
+        /// <summary>
+        /// Places the label inside the pie slice
+        /// </summary>
+        InsideSlice,
+        /// <summary>
+        /// Places the label outside the pie slice
+        /// </summary>
+        OutsideSlice
+    }
+}

Core40/Core40.csproj

@@ -137,6 +137,7 @@
     <Compile Include="LogarithmicAxisCore.cs" />
     <Compile Include="Maps\MapData.cs" />
     <Compile Include="PanningOptions.cs" />
+    <Compile Include="PieLabelPosition.cs" />
     <Compile Include="PointTracker.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ScrollMode.cs" />

Core40/PieLabelPosition.cs

@@ -0,0 +1,39 @@
+//The MIT License(MIT)
+
+//copyright(c) 2016 Alberto Rodriguez
+
+//Permission is hereby granted, free of charge, to any person obtaining a copy
+//of this software and associated documentation files (the "Software"), to deal
+//in the Software without restriction, including without limitation the rights
+//to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+//copies of the Software, and to permit persons to whom the Software is
+//furnished to do so, subject to the following conditions:
+
+//The above copyright notice and this permission notice shall be included in all
+//copies or substantial portions of the Software.
+
+//THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+//IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+//FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+//AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+//LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+//OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+//SOFTWARE.
+
+namespace LiveCharts
+{
+    /// <summary>
+    /// Describes where a label should be placed
+    /// </summary>
+    public enum PieLabelPosition
+    {
+        /// <summary>
+        /// Places the label inside the pie slice
+        /// </summary>
+        InsideSlice,
+        /// <summary>
+        /// Places the label outside the pie slice
+        /// </summary>
+        OutsideSlice
+    }
+}

WpfView/PieSeries.cs

@@ -79,6 +79,25 @@ public double PushOut
             get { return (double) GetValue(PushOutProperty); }
             set { SetValue(PushOutProperty, value); }
         }
+
+        /// <summary>
+        /// The label position property
+        /// </summary>
+        public static readonly DependencyProperty LabelPositionProperty = DependencyProperty.Register(
+            "LabelPosition", typeof(PieLabelPosition), typeof(PieSeries), 
+            new PropertyMetadata(PieLabelPosition.InsideSlice, CallChartUpdater()));
+        /// <summary>
+        /// Gets or sets the label position.
+        /// </summary>
+        /// <value>
+        /// The label position.
+        /// </value>
+        public PieLabelPosition LabelPosition
+        {
+            get { return (PieLabelPosition) GetValue(LabelPositionProperty); }
+            set { SetValue(LabelPositionProperty, value); }
+        }
+
         #endregion
 
         #region Overridden Methods

WpfView/Points/PiePointView.cs

@@ -52,8 +52,8 @@ public override void DrawOrMove(ChartPoint previousDrawn, ChartPoint current, in
 
             if (DataLabel != null && double.IsNaN(Canvas.GetLeft(DataLabel)))
             {
-                Canvas.SetTop(DataLabel, 0d);
-                Canvas.SetLeft(DataLabel, 0d);
+                Canvas.SetTop(DataLabel, chart.DrawMargin.Height/2);
+                Canvas.SetLeft(DataLabel, chart.DrawMargin.Width/2);
             }
 
             if (HoverShape != null)
@@ -68,25 +68,31 @@ public override void DrawOrMove(ChartPoint previousDrawn, ChartPoint current, in
                 hs.Radius = Radius;
             }
 
-            Canvas.SetTop(Slice, chart.DrawMargin.Height / 2);
-            Canvas.SetLeft(Slice, chart.DrawMargin.Width / 2);
-            Slice.InnerRadius = InnerRadius;
-            Slice.Radius = Radius;
+            var lh = 0d;
+            if (DataLabel != null)
+            {
+                DataLabel.UpdateLayout();
+                lh = DataLabel.ActualHeight;
+            }
 
-            var hypo = (Slice.Radius + Slice.InnerRadius)/2;
+            var hypo = ((PieSeries) current.SeriesView).LabelPosition == PieLabelPosition.InsideSlice
+                ? (Radius + InnerRadius)*(Math.Abs(InnerRadius) < 0.01 ? .65 : .5)
+                : Radius + lh;
             var gamma = current.Participation*360/2 + Rotation;
             var cp = new Point(hypo * Math.Sin(gamma * (Math.PI / 180)), hypo * Math.Cos(gamma * (Math.PI / 180)));
 
             if (chart.View.DisableAnimations)
             {
+                Slice.InnerRadius = InnerRadius;
+                Slice.Radius = Radius;
                 Slice.WedgeAngle = Wedge;
                 Slice.RotationAngle = Rotation;
+                Canvas.SetTop(Slice, chart.DrawMargin.Height / 2);
+                Canvas.SetLeft(Slice, chart.DrawMargin.Width / 2);
 
                 if (DataLabel != null)
                 {
-                    DataLabel.UpdateLayout();
-
-                    var lx = cp.X + chart.DrawMargin.Width / 2 - DataLabel.ActualWidth * .5;
+                    var lx = cp.X + chart.DrawMargin.Width/2 - DataLabel.ActualWidth * .5;
                     var ly = chart.DrawMargin.Height/2 - cp.Y - DataLabel.ActualHeight*.5;
 
                     Canvas.SetLeft(DataLabel, lx);
@@ -102,13 +108,19 @@ public override void DrawOrMove(ChartPoint previousDrawn, ChartPoint current, in
             {
                 DataLabel.UpdateLayout();
 
-                var lx = cp.X + chart.DrawMargin.Width / 2 - DataLabel.ActualWidth * .5;
-                var ly = chart.DrawMargin.Height / 2 - cp.Y - DataLabel.ActualHeight * .5;
+                var lx = cp.X + chart.DrawMargin.Width/2 - DataLabel.ActualWidth * .5;
+                var ly = chart.DrawMargin.Height/2 - cp.Y - DataLabel.ActualHeight * .5;
 
                 DataLabel.BeginAnimation(Canvas.LeftProperty, new DoubleAnimation(lx, animSpeed));
                 DataLabel.BeginAnimation(Canvas.TopProperty, new DoubleAnimation(ly, animSpeed));
             }
 
+            Slice.BeginAnimation(Canvas.LeftProperty, 
+                new DoubleAnimation(chart.DrawMargin.Width / 2, animSpeed));
+            Slice.BeginAnimation(Canvas.TopProperty,
+                new DoubleAnimation(chart.DrawMargin.Height/2, animSpeed));
+            Slice.BeginAnimation(PieSlice.InnerRadiusProperty, new DoubleAnimation(InnerRadius, animSpeed));
+            Slice.BeginAnimation(PieSlice.RadiusProperty, new DoubleAnimation(Radius, animSpeed));
             Slice.BeginAnimation(PieSlice.WedgeAngleProperty, new DoubleAnimation(Wedge, animSpeed));
             Slice.BeginAnimation(PieSlice.RotationAngleProperty, new DoubleAnimation(Rotation, animSpeed));
         }