From bc404de9379f8ad301a255dc22a3d69f5cd43f65 Mon Sep 17 00:00:00 2001
From: leo <longshuang@msn.cn>
Date: Thu, 13 Jan 2022 10:54:45 +0800
Subject: [PATCH] feature<Statistics>: show hovered sample tooltip in chart

---
 src/Views/Controls/Chart.cs | 57 ++++++++++++++++++++++++++++++-------
 1 file changed, 46 insertions(+), 11 deletions(-)

diff --git a/src/Views/Controls/Chart.cs b/src/Views/Controls/Chart.cs
index faa0652d..aed1fecb 100644
--- a/src/Views/Controls/Chart.cs
+++ b/src/Views/Controls/Chart.cs
@@ -2,6 +2,7 @@
 using System.Collections.Generic;
 using System.Globalization;
 using System.Windows;
+using System.Windows.Input;
 using System.Windows.Media;
 
 namespace SourceGit.Views.Controls {
@@ -34,8 +35,9 @@ namespace SourceGit.Views.Controls {
             set { SetValue(ChartBrushProperty, value); }
         }
 
-        private int maxV = 0;
         private List<Models.StatisticSample> samples = new List<Models.StatisticSample>();
+        private List<Rect> hitboxes = new List<Rect>();
+        private int maxV = 0;
 
         /// <summary>
         ///     设置绘制数据
@@ -43,13 +45,19 @@ namespace SourceGit.Views.Controls {
         /// <param name="samples">数据源</param>
         public void SetData(List<Models.StatisticSample> samples) {
             this.samples = samples;
-            maxV = 0;
+            this.hitboxes.Clear();
 
+            maxV = 0;
             foreach (var s in samples) {
                 if (maxV < s.Count) maxV = s.Count;
             }
-
             maxV = (int)Math.Ceiling(maxV / 10.0) * 10;
+            
+            InvalidateVisual();
+        }
+
+        protected override void OnMouseMove(MouseEventArgs e) {
+            base.OnMouseMove(e);
             InvalidateVisual();
         }
 
@@ -78,18 +86,25 @@ namespace SourceGit.Views.Controls {
 
                 var dashHeight = i * stepV;
                 var vy = Math.Max(0, dashHeight - vLabel.Height * 0.5);
+                dc.PushOpacity(.1);
                 dc.DrawLine(gridPen, new Point(LABEL_UNIT + 1, dashHeight), new Point(ActualWidth, dashHeight));
+                dc.Pop();
                 dc.DrawText(vLabel, new Point(0, vy));
             }
 
             var stepX = (ActualWidth - LABEL_UNIT) / samples.Count;
-            var shapeWidth = Math.Min(LABEL_UNIT, stepX - 4);
-            for (int i = 0; i < samples.Count; i++) {
-                var h = samples[i].Count * (ActualHeight - LABEL_UNIT) / maxV;
-                var x = LABEL_UNIT + 1 + stepX * i + (stepX - shapeWidth) * 0.5;
-                var y = ActualHeight - LABEL_UNIT - h;
-                var rect = new Rect(x, y, shapeWidth, h);
+            if (hitboxes.Count == 0) {
+                var shapeWidth = Math.Min(LABEL_UNIT, stepX - 4);
+                for (int i = 0; i < samples.Count; i++) {
+                    var h = samples[i].Count * (ActualHeight - LABEL_UNIT) / maxV;
+                    var x = LABEL_UNIT + 1 + stepX * i + (stepX - shapeWidth) * 0.5;
+                    var y = ActualHeight - LABEL_UNIT - h;
+                    hitboxes.Add(new Rect(x, y, shapeWidth, h));
+                }
+            }
 
+            var mouse = Mouse.GetPosition(this);
+            for (int i = 0; i < samples.Count; i++) {
                 var hLabel = new FormattedText(
                     samples[i].Name,
                     CultureInfo.CurrentCulture,
@@ -98,7 +113,8 @@ namespace SourceGit.Views.Controls {
                     10.0,
                     LineBrush,
                     VisualTreeHelper.GetDpi(this).PixelsPerDip);
-                var xLabel = x - (hLabel.Width - shapeWidth) * 0.5;
+                var rect = hitboxes[i];
+                var xLabel = rect.X - (hLabel.Width - rect.Width) * 0.5;
                 var yLabel = ActualHeight - LABEL_UNIT + 4;
 
                 dc.DrawRectangle(ChartBrush, null, rect);
@@ -111,7 +127,26 @@ namespace SourceGit.Views.Controls {
                     dc.Pop();
                 } else {
                     dc.DrawText(hLabel, new Point(xLabel, yLabel));
-                }                
+                }           
+            }
+
+            for (int i = 0; i < samples.Count; i++) {
+                var rect = hitboxes[i];
+                if (rect.Contains(mouse)) {
+                    var tooltip = new FormattedText(
+                        $"{samples[i].Count}",
+                        CultureInfo.CurrentCulture,
+                        FlowDirection.LeftToRight,
+                        new Typeface(font, FontStyles.Normal, FontWeights.Normal, FontStretches.Normal),
+                        12.0,
+                        FindResource("Brush.FG1") as Brush,
+                        VisualTreeHelper.GetDpi(this).PixelsPerDip);
+
+                    var tx = rect.X - (tooltip.Width - rect.Width) * 0.5;
+                    var ty = rect.Y - tooltip.Height - 4;
+                    dc.DrawText(tooltip, new Point(tx, ty));
+                    break;
+                }
             }
         }
     }