code review fixes

LibreHardwareMonitor.Windows.WinUI.Tests/Controls/PlotViewTests.cs

@@ -0,0 +1,57 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using LibreHardwareMonitor.Windows.WinUI.Controls;
+using LibreHardwareMonitor.Windows.WinUI.ViewModels;
+using Xunit;
+
+namespace LibreHardwareMonitor.Windows.WinUI.Tests.Controls;
+
+public class PlotViewTests
+{
+    [Fact]
+    public void DecimatePoints_ReturnsOriginalList_WhenPointsCountSmall()
+    {
+        var points = new List<PlotPointViewModel>
+        {
+            new(DateTime.UtcNow, 1.0),
+            new(DateTime.UtcNow.AddSeconds(1), 2.0),
+            new(DateTime.UtcNow.AddSeconds(2), 3.0),
+        };
+
+        var result = PlotView.DecimatePoints(points, 10);
+
+        Assert.Equal(points.Count, result.Count);
+        Assert.Equal(points, result);
+    }
+
+    [Fact]
+    public void DecimatePoints_DecimatesAndMaintainsEnvelope_WhenPointsCountLarge()
+    {
+        // 1000 points, decimate to targetWidth = 100
+        var points = new List<PlotPointViewModel>();
+        var baseTime = DateTime.UtcNow;
+        for (int i = 0; i < 1000; i++)
+        {
+            // Create a sine wave with some noise/spikes
+            double val = Math.Sin(i * 0.1);
+            if (i == 505) val = 100.0; // extreme max spike
+            if (i == 510) val = -100.0; // extreme min spike
+            points.Add(new PlotPointViewModel(baseTime.AddSeconds(i), val));
+        }
+
+        var result = PlotView.DecimatePoints(points, 100);
+
+        // Result should be decimated (less than original, but bounds preserved)
+        Assert.True(result.Count < points.Count);
+        Assert.True(result.Count >= 100);
+
+        // Extreme spike values must be preserved in the output
+        Assert.Contains(result, p => p.Value == 100.0);
+        Assert.Contains(result, p => p.Value == -100.0);
+
+        // Rightmost point (latest sample) must be exactly preserved
+        Assert.Equal(points[^1].Timestamp, result[^1].Timestamp);
+        Assert.Equal(points[^1].Value, result[^1].Value);
+    }
+}

LibreHardwareMonitor.Windows.WinUI/Controls/PlotView.cs

@@ -458,7 +458,9 @@ public sealed class PlotView : Grid
             StrokeLineJoin = PenLineJoin.Round
         };
 
-        foreach (PlotPointViewModel point in sample.Points)
+        IReadOnlyList<PlotPointViewModel> decimatedPoints = DecimatePoints(sample.Points, (int)Math.Max(100, bounds.Width));
+
+        foreach (PlotPointViewModel point in decimatedPoints)
         {
             double x = bounds.Left + (point.Timestamp - minTimestamp).Ticks / (double)rangeTicks * bounds.Width;
             double y = axis.Bottom - ((point.Value - axis.MinValue) / (axis.MaxValue - axis.MinValue) * axis.Height);
@@ -470,6 +472,57 @@ public sealed class PlotView : Grid
             DrawPointMarker(canvas, line.Points[^1], stroke);
     }
 
+    internal static IReadOnlyList<PlotPointViewModel> DecimatePoints(IReadOnlyList<PlotPointViewModel> points, int targetWidth)
+    {
+        if (points.Count <= targetWidth * 2)
+            return points;
+
+        List<PlotPointViewModel> result = new();
+        int bucketSize = points.Count / targetWidth;
+        if (bucketSize <= 1)
+            return points;
+
+        for (int i = 0; i < targetWidth; i++)
+        {
+            int start = i * bucketSize;
+            int end = (i == targetWidth - 1) ? points.Count : (i + 1) * bucketSize;
+            if (start >= end)
+                break;
+
+            int minIdx = start;
+            int maxIdx = start;
+            for (int j = start + 1; j < end; j++)
+            {
+                if (points[j].Value < points[minIdx].Value)
+                    minIdx = j;
+                if (points[j].Value > points[maxIdx].Value)
+                    maxIdx = j;
+            }
+
+            if (minIdx == maxIdx)
+            {
+                result.Add(points[minIdx]);
+            }
+            else if (minIdx < maxIdx)
+            {
+                result.Add(points[minIdx]);
+                result.Add(points[maxIdx]);
+            }
+            else
+            {
+                result.Add(points[maxIdx]);
+                result.Add(points[minIdx]);
+            }
+        }
+
+        if (result.Count > 0 && result[^1].Timestamp != points[^1].Timestamp)
+        {
+            result.Add(points[^1]);
+        }
+
+        return result;
+    }
+
     private void DrawPlotMessage(Canvas canvas, PlotBounds bounds, string message)
     {
         TextBlock label = CreatePlotLabel(message, new SolidColorBrush(GetPlotTextColor()), 13, 600);

LibreHardwareMonitor.Windows.WinUI/Services/WindowPlacementService.cs

@@ -66,16 +66,25 @@ internal sealed class WindowPlacementService
 
     public void Maximize()
     {
-        if (_appWindow.Presenter is OverlappedPresenter presenter)
+        if (_settings.GetValue(_settingPrefix + "Maximized", false) && _appWindow.Presenter is OverlappedPresenter presenter)
             presenter.Maximize();
     }
 
     public void Save()
     {
-        _settings.SetValue(_settingPrefix + "Location.X", _appWindow.Position.X);
-        _settings.SetValue(_settingPrefix + "Location.Y", _appWindow.Position.Y);
-        _settings.SetValue(_settingPrefix + "Width", _appWindow.Size.Width);
-        _settings.SetValue(_settingPrefix + "Height", _appWindow.Size.Height);
+        if (_appWindow.Presenter is OverlappedPresenter presenter)
+        {
+            bool maximized = presenter.State == OverlappedPresenterState.Maximized;
+            _settings.SetValue(_settingPrefix + "Maximized", maximized);
+
+            if (presenter.State == OverlappedPresenterState.Restored)
+            {
+                _settings.SetValue(_settingPrefix + "Location.X", _appWindow.Position.X);
+                _settings.SetValue(_settingPrefix + "Location.Y", _appWindow.Position.Y);
+                _settings.SetValue(_settingPrefix + "Width", _appWindow.Size.Width);
+                _settings.SetValue(_settingPrefix + "Height", _appWindow.Size.Height);
+            }
+        }
     }
 
     [DllImport("user32.dll")]