From 648f43b862f889bc817e4c319119839ca4b37b08 Mon Sep 17 00:00:00 2001
From: Mark Monteiro <mark@sentisolutions.ca>
Date: Mon, 26 Jul 2021 10:33:14 -0400
Subject: [PATCH] Use a virtual method for measuring each paint task in
 DrawMarginFrame

This refactoring makes it easier for sub-classes to implement custom rendering logic
---
 src/LiveChartsCore/DrawMarginFrame.cs | 59 +++++++++++++++++----------
 1 file changed, 37 insertions(+), 22 deletions(-)

diff --git a/src/LiveChartsCore/DrawMarginFrame.cs b/src/LiveChartsCore/DrawMarginFrame.cs
index 16e89e575..b410c68db 100644
--- a/src/LiveChartsCore/DrawMarginFrame.cs
+++ b/src/LiveChartsCore/DrawMarginFrame.cs
@@ -114,38 +114,53 @@ public abstract class DrawMarginFrame<TSizedGeometry, TDrawingContext> : DrawMar
         /// <param name="chart">The chart.</param>
         public override void Measure(Chart<TDrawingContext> chart)
         {
-            var drawLocation = chart.DrawMarginLocation;
-            var drawMarginSize = chart.DrawMarginSize;
-
             if (Fill is not null)
             {
-                Fill.ZIndex = -3;
-
-                _fillSizedGeometry ??= new TSizedGeometry();
-
-                _fillSizedGeometry.X = drawLocation.X;
-                _fillSizedGeometry.Y = drawLocation.Y;
-                _fillSizedGeometry.Width = drawMarginSize.Width;
-                _fillSizedGeometry.Height = drawMarginSize.Height;
-
-                Fill.AddGeometryToPaintTask(chart.Canvas, _fillSizedGeometry);
+                MeasureFill(chart);
                 chart.Canvas.AddDrawableTask(Fill);
             }
 
             if (Stroke is not null)
             {
-                Stroke.ZIndex = -2;
+                MeasureStroke(chart);
+                chart.Canvas.AddDrawableTask(Stroke);
+            }
+        }
 
-                _strokeSizedGeometry ??= new TSizedGeometry();
+        /// <summary>
+        /// Measures the <see cref="DrawMarginFrame{TDrawingContext}.Fill"/> of the draw margin for the specified chart.
+        /// </summary>
+        /// <param name="chart">The chart.</param>
+        protected virtual void MeasureFill(Chart<TDrawingContext> chart)
+        {
+            Fill!.ZIndex = -3;
 
-                _strokeSizedGeometry.X = drawLocation.X;
-                _strokeSizedGeometry.Y = drawLocation.Y;
-                _strokeSizedGeometry.Width = drawMarginSize.Width;
-                _strokeSizedGeometry.Height = drawMarginSize.Height;
+            _fillSizedGeometry ??= new TSizedGeometry();
 
-                Stroke.AddGeometryToPaintTask(chart.Canvas, _strokeSizedGeometry);
-                chart.Canvas.AddDrawableTask(Stroke);
-            }
+            _fillSizedGeometry.X = chart.DrawMarginLocation.X;
+            _fillSizedGeometry.Y = chart.DrawMarginLocation.Y;
+            _fillSizedGeometry.Width = chart.DrawMarginSize.Width;
+            _fillSizedGeometry.Height = chart.DrawMarginSize.Height;
+
+            Fill.AddGeometryToPaintTask(chart.Canvas, _fillSizedGeometry);
+        }
+
+        /// <summary>
+        /// Measures the <see cref="DrawMarginFrame{TDrawingContext}.Stroke"/> of the draw margin for the specified chart.
+        /// </summary>
+        /// <param name="chart">The chart.</param>
+        protected virtual void MeasureStroke(Chart<TDrawingContext> chart)
+        {
+            Stroke!.ZIndex = -2;
+
+            _strokeSizedGeometry ??= new TSizedGeometry();
+
+            _strokeSizedGeometry.X = chart.DrawMarginLocation.X;
+            _strokeSizedGeometry.Y = chart.DrawMarginLocation.Y;
+            _strokeSizedGeometry.Width = chart.DrawMarginSize.Width;
+            _strokeSizedGeometry.Height = chart.DrawMarginSize.Height;
+
+            Stroke.AddGeometryToPaintTask(chart.Canvas, _strokeSizedGeometry);
         }
     }
 }