更新

COFTester/Controls/RealtimeForceChart.cs

@@ -280,22 +280,7 @@ public sealed class RealtimeForceChart : FrameworkElement
 
     private static int ResolveXAxisDivisions(double plotWidth)
     {
-        if (plotWidth >= 700)
-        {
-            return 10;
-        }
-
-        if (plotWidth >= 520)
-        {
-            return 8;
-        }
-
-        if (plotWidth >= 360)
-        {
-            return 6;
-        }
-
-        return 4;
+        return Math.Clamp((int)Math.Ceiling(plotWidth / 110), 4, 240);
     }
 
     private void DrawCenteredText(

COFTester/MainWindow.xaml

@@ -251,21 +251,31 @@
                         <RowDefinition Height="300" />
                     </Grid.RowDefinitions>
 
-                    <controls:RealtimeForceChart x:Name="RealtimeForceChart"
-                                                 Grid.Row="0"
-                                                 Margin="0,0,0,8"
-                                                 HorizontalAlignment="Stretch"
-                                                 VerticalAlignment="Stretch"
-                                                 Samples="{Binding RealtimeForceSamples}"
-                                                 PeakLineSamples="{Binding RealtimePeakLineSamples}"
-                                                 AverageLineSamples="{Binding RealtimeAverageLineSamples}"
-                                                 CurrentPointSamples="{Binding RealtimeCurrentPointSamples}"
-                                                 XMax="{Binding RealtimeChartXMax}"
-                                                 YMax="{Binding RealtimeChartYMax}"
-                                                 TravelMm="{Binding Recipe.TravelMm}"
-                                                 SledMassGrams="{Binding Recipe.SledMassGrams}"
-                                                 Loaded="RealtimeForceChart_Loaded"
-                                                 SizeChanged="RealtimeForceChart_SizeChanged" />
+                    <ScrollViewer x:Name="RealtimeChartScrollViewer"
+                                  Grid.Row="0"
+                                  Margin="0,0,0,8"
+                                  HorizontalScrollBarVisibility="Auto"
+                                  VerticalScrollBarVisibility="Disabled"
+                                  CanContentScroll="False"
+                                  Loaded="RealtimeChartScrollViewer_Loaded"
+                                  ScrollChanged="RealtimeChartScrollViewer_ScrollChanged">
+                        <controls:RealtimeForceChart x:Name="RealtimeForceChart"
+                                                     Width="{Binding RealtimeChartCanvasWidth}"
+                                                     MinWidth="{Binding ViewportWidth, ElementName=RealtimeChartScrollViewer}"
+                                                     Height="{Binding ViewportHeight, ElementName=RealtimeChartScrollViewer}"
+                                                     HorizontalAlignment="Left"
+                                                     VerticalAlignment="Stretch"
+                                                     Samples="{Binding RealtimeForceSamples}"
+                                                     PeakLineSamples="{Binding RealtimePeakLineSamples}"
+                                                     AverageLineSamples="{Binding RealtimeAverageLineSamples}"
+                                                     CurrentPointSamples="{Binding RealtimeCurrentPointSamples}"
+                                                     XMax="{Binding RealtimeChartXMax}"
+                                                     YMax="{Binding RealtimeChartYMax}"
+                                                     TravelMm="{Binding Recipe.TravelMm}"
+                                                     SledMassGrams="{Binding Recipe.SledMassGrams}"
+                                                     Loaded="RealtimeForceChart_Loaded"
+                                                     SizeChanged="RealtimeForceChart_SizeChanged" />
+                    </ScrollViewer>
 
                     <Border Grid.Row="1" Style="{StaticResource PanelBorderStyle}" Padding="10" Margin="0,0,0,8">
                         <Grid>

COFTester/MainWindow.xaml.cs

@@ -15,6 +15,7 @@ public partial class MainWindow : Window
     private readonly MainViewModel _viewModel = new();
     private readonly DispatcherTimer _realtimeChartRenderTimer;
     private bool _isRealtimeChartLayoutRefreshQueued;
+    private bool _isRealtimeChartAutoScrollPinned = true;
     private DateTime _realtimeChartRenderUntilUtc = DateTime.MinValue;
 
     public MainWindow()
@@ -73,6 +74,30 @@ public partial class MainWindow : Window
         RequestRealtimeChartRender(RealtimeChartStartupRenderPulseDuration);
     }
 
+    private void RealtimeChartScrollViewer_Loaded(object sender, RoutedEventArgs e)
+    {
+        _isRealtimeChartAutoScrollPinned = true;
+        RequestRealtimeChartRender(RealtimeChartStartupRenderPulseDuration);
+    }
+
+    private void RealtimeChartScrollViewer_ScrollChanged(object sender, ScrollChangedEventArgs e)
+    {
+        if (e.ExtentWidthChange < -1)
+        {
+            _isRealtimeChartAutoScrollPinned = true;
+            ScrollRealtimeChartToEndIfPinned();
+            return;
+        }
+
+        if (Math.Abs(e.ExtentWidthChange) > 0 || Math.Abs(e.ViewportWidthChange) > 0)
+        {
+            ScrollRealtimeChartToEndIfPinned();
+            return;
+        }
+
+        _isRealtimeChartAutoScrollPinned = IsRealtimeChartScrolledToEnd();
+    }
+
     private void RealtimeForceChart_SizeChanged(object sender, SizeChangedEventArgs e)
     {
         if (e.NewSize.Width <= 0 || e.NewSize.Height <= 0)
@@ -196,5 +221,29 @@ public partial class MainWindow : Window
         RealtimeForceChart.InvalidateArrange();
         RealtimeForceChart.InvalidateVisual();
         RealtimeForceChart.UpdateLayout();
+        RealtimeChartScrollViewer.UpdateLayout();
+        ScrollRealtimeChartToEndIfPinned();
+    }
+
+    private bool IsRealtimeChartScrolledToEnd()
+    {
+        const double tolerance = 8;
+        return RealtimeChartScrollViewer.HorizontalOffset >= RealtimeChartScrollViewer.ScrollableWidth - tolerance;
+    }
+
+    private void ScrollRealtimeChartToEndIfPinned()
+    {
+        if (!_isRealtimeChartAutoScrollPinned)
+        {
+            return;
+        }
+
+        if (RealtimeChartScrollViewer.ScrollableWidth <= 0)
+        {
+            RealtimeChartScrollViewer.ScrollToHorizontalOffset(0);
+            return;
+        }
+
+        RealtimeChartScrollViewer.ScrollToHorizontalOffset(RealtimeChartScrollViewer.ScrollableWidth);
     }
 }

COFTester/ViewModels/MainViewModel.cs

@@ -56,6 +56,8 @@ public sealed class MainViewModel : ObservableObject, IDisposable
     private static readonly TimeSpan RealtimeChartRefreshInterval = TimeSpan.FromMilliseconds(250);
     private const double RealtimeChartTimeStepSeconds = 0.05;
     private const double RealtimeChartXAxisPaddingSeconds = 1;
+    private const double RealtimeChartMinimumCanvasWidth = 900;
+    private const double RealtimeChartPixelsPerSecond = 18;
     private const double MinimumEmptyChartXAxisMaxLimit = 1;
     private const double EmptyChartYAxisMaxLimit = 0.5;
     private const double EmptyChartPointForceN = 0.001;
@@ -308,6 +310,8 @@ public sealed class MainViewModel : ObservableObject, IDisposable
 
     public double RealtimeChartXMax => _lastForceXAxisMaxLimit;
 
+    public double RealtimeChartCanvasWidth => Math.Max(RealtimeChartMinimumCanvasWidth, _lastForceXAxisMaxLimit * RealtimeChartPixelsPerSecond);
+
     public double RealtimeChartYMax => _lastForceYAxisMaxLimit;
 
     public RelayCommand StartCommand => _startCommand;
@@ -1306,6 +1310,7 @@ public sealed class MainViewModel : ObservableObject, IDisposable
             OnPropertyChanged(nameof(ForceXAxes));
             OnPropertyChanged(nameof(ForceYAxes));
             OnPropertyChanged(nameof(RealtimeChartXMax));
+            OnPropertyChanged(nameof(RealtimeChartCanvasWidth));
             OnPropertyChanged(nameof(RealtimeChartYMax));
         }
     }
@@ -1319,6 +1324,7 @@ public sealed class MainViewModel : ObservableObject, IDisposable
         OnPropertyChanged(nameof(ForceXAxes));
         OnPropertyChanged(nameof(ForceYAxes));
         OnPropertyChanged(nameof(RealtimeChartXMax));
+        OnPropertyChanged(nameof(RealtimeChartCanvasWidth));
         OnPropertyChanged(nameof(RealtimeChartYMax));
         NotifyRealtimeChartChanged();
     }