Cache and Dispose Brushes in GraphicsRenderContext (oxyplot#1230)

Author: VisualMelon

CHANGELOG.md

@@ -55,6 +55,7 @@ All notable changes to this project will be documented in this file.
 - Candle overlap each candle (#623)
 - CandleStick is overlapped when item.open == item.close in the CandleStickAndVolumeSeries (#1245)
 - Out of memory exception and performance issue with Catmull-Rom Spline (#1237)
+- Cache and Dispose Brush and Pen objects used by GraphicsRenderContext (#1230)
 
 ## [1.0.0] - 2016-09-11
 ### Added

Source/OxyPlot.WindowsForms/GraphicsRenderContext.cs

@@ -171,7 +171,7 @@ public override void DrawPolygon(
             var pts = this.ToPoints(points);
             if (fill.IsVisible())
             {
-                this.g.FillPolygon(fill.ToBrush(), pts);
+                this.g.FillPolygon(this.GetCachedBrush(fill), pts);
             }
 
             if (stroke.IsInvisible() || thickness <= 0)
@@ -214,7 +214,7 @@ public override void DrawRectangle(OxyRect rect, OxyColor fill, OxyColor stroke,
             if (fill.IsVisible())
             {
                 this.g.FillRectangle(
-                    fill.ToBrush(), (float)rect.Left, (float)rect.Top, (float)rect.Width, (float)rect.Height);
+                    this.GetCachedBrush(fill), (float)rect.Left, (float)rect.Top, (float)rect.Width, (float)rect.Height);
             }
 
             if (stroke.IsInvisible() || thickness <= 0)
@@ -304,18 +304,18 @@ public override void DrawText(
                 var graphicsState = this.g.Save();
 
                 this.g.TranslateTransform((float)p.X, (float)p.Y);
-                
+
                 var layoutRectangle = new RectangleF(0, 0, size.Width, size.Height);
                 if (Math.Abs(rotate) > double.Epsilon)
                 {
                     this.g.RotateTransform((float)rotate);
-                    
+
                     layoutRectangle.Height += (float)(fontSize / 18.0);
                 }
 
                 this.g.TranslateTransform(dx, dy);
 
-                this.g.DrawString(text, font, fill.ToBrush(), layoutRectangle, this.stringFormat);
+                this.g.DrawString(text, font, this.GetCachedBrush(fill), layoutRectangle, this.stringFormat);
 
                 this.g.Restore(graphicsState);
             }

Source/OxyPlot.WindowsForms/PlotView.cs

@@ -316,7 +316,7 @@ public void ShowTracker(TrackerHitResult data)
 
             this.trackerLabel.Text = data.ToString();
             this.trackerLabel.Top = (int)data.Position.Y - this.trackerLabel.Height;
-            this.trackerLabel.Left = (int)data.Position.X - this.trackerLabel.Width / 2;
+            this.trackerLabel.Left = (int)data.Position.X - (this.trackerLabel.Width / 2);
             this.trackerLabel.Visible = true;
         }
 
@@ -503,13 +503,35 @@ protected override void OnResize(EventArgs e)
             this.InvalidatePlot(false);
         }
 
+        /// <summary>
+        /// Disposes the PlotView.
+        /// </summary>
+        /// <param name="disposing">Whether to dispose managed resources or not.</param>
+        protected override void Dispose(bool disposing)
+        {
+            bool disposed = this.IsDisposed;
+
+            base.Dispose(disposing);
+
+            if (disposed)
+            {
+                return;
+            }
+
+            if (disposing)
+            {
+                this.renderContext.Dispose();
+            }
+        }
+
         /// <summary>
         /// Gets the current modifier keys.
         /// </summary>
         /// <returns>A <see cref="OxyModifierKeys" /> value.</returns>
         private static OxyModifierKeys GetModifiers()
         {
             var modifiers = OxyModifierKeys.None;
+
             // ReSharper disable once RedundantNameQualifier
             if ((Control.ModifierKeys & Keys.Shift) == Keys.Shift)
             {