Merge branch 'main' into fix-datetimeautomatic-inverted-axes

Author: swharden

CHANGELOG.md

@@ -1,5 +1,11 @@
 ## ScottPlot 5.0.56
 _Not yet on NuGet..._
+* Statistics: Added support for kernel density estimation with Epanechnikov, Gaussian, Uniform, and Triangular strategies. Scott's rule (no relation) was implemented for bandwidth estimation (#4869) @bclehmann
+* Radar: Added a `IsAxisAboveData` property to allow the axes to be rendered on top of the data series (#4874) @Christoph-Wagner
+* Scatter: Add support for vertically oriented gradient fills (#4881) @manaruto
+* Bar Plot: Add `LabelsOnTop` option to allow bar labels to always be displayed and never get overlapped by other bars or plottables (#4886, #4855) @manaruto @bclehmann
+* PolarAxis: Add support for custom background color (#4897) @CoderPM2011
+* PolarAxis: Added support for custom spoke lengths (#4897) @CoderPM2011
 
 ## ScottPlot 5.0.55
 _Published on [NuGet](https://www.nuget.org/profiles/ScottPlot) on 2025-03-22_

src/ScottPlot5/ScottPlot5 Cookbook/Recipes/Miscellaneous/KernelDensityEstimation.cs

@@ -0,0 +1,72 @@
+using ScottPlot.Statistics;
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+using System.Threading.Tasks;
+
+namespace ScottPlotCookbook.Recipes.Miscellaneous;
+
+public class KernelDensityEstimation : ICategory
+{
+    public Chapter Chapter => Chapter.General;
+    public string CategoryName => "Kernel Density Estimation";
+    public string CategoryDescription => "Kernel Density Estimation (KDE) can be used to estimate a PDF for a histogram, allowing the creation of density plots";
+    public class KdeQuickstart : RecipeBase
+    {
+        public override string Name => "Density Plot";
+        public override string Description => "Density Plots use KDE to estimate a PDF.";
+
+        [Test]
+        public override void Execute()
+        {
+            var ys = SampleData.Faithful;
+
+            var hist = Histogram.WithBinCount(80, ys);
+
+            var histPlot = myPlot.Add.Histogram(hist);
+            histPlot.BarWidthFraction = 0.8;
+
+            var densityEstimate = hist.Bins.Select((x, i) => KernelDensity.Estimate(x, ys)).ToArray();
+            double scale = ys.Length;
+
+            var rescaledDensityEstimate = densityEstimate.Select(x => x * scale).ToArray();
+
+            var scat = myPlot.Add.Scatter(hist.Bins, rescaledDensityEstimate, Colors.Red);
+            scat.MarkerSize = 0;
+        }
+    }
+
+    public class KdeKernelOptions : RecipeBase
+    {
+        public override string Name => "Density Plot Kernels";
+        public override string Description => "Several choices of kernels are available.";
+
+        [Test]
+        public override void Execute()
+        {
+            var ys = SampleData.Faithful;
+
+            var hist = Histogram.WithBinCount(80, ys);
+
+            var histPlot = myPlot.Add.Histogram(hist);
+            histPlot.BarWidthFraction = 0.8;
+            foreach (var bar in histPlot.Bars)
+            {
+                bar.FillColor = Colors.LightBlue;
+            }
+
+            foreach (var kernel in Enum.GetValues<KdeKernel>())
+            {
+                var densityEstimate = hist.Bins.Select((x, i) => KernelDensity.Estimate(x, ys, kernel)).ToArray();
+                double scale = ys.Length;
+
+                var rescaledDensityEstimate = densityEstimate.Select(x => x * scale).ToArray();
+
+                var scat = myPlot.Add.Scatter(hist.Bins, rescaledDensityEstimate);
+                scat.MarkerSize = 0;
+                scat.LegendText = kernel.ToString();
+            }
+        }
+    }
+}

src/ScottPlot5/ScottPlot5 Cookbook/Recipes/PlotTypes/Bar.cs

@@ -101,6 +101,49 @@ public override void Execute()
         }
     }
 
+    public class BarLabelsLast : RecipeBase
+    {
+        public override string Name => "Labels on Top";
+        public override string Description => "Bars with labels are rendered one at a time by default, " +
+            "but this makes it possible for bar labels to get overlapped by other bars. " +
+            "Bar chars may be configured to render labels last, even above other plottables.";
+
+        [Test]
+        public override void Execute()
+        {
+            double[] values = Generate.Consecutive(5, first: 1);
+
+            // create two bar plots
+            var bars1 = myPlot.Add.Bars(values);
+            var bars2 = myPlot.Add.Bars(values);
+
+            // enable the LabelsOnTop feature on one of the bars
+            bars2.LabelsOnTop = true;
+
+            // give each bar a label and style it to demonstrate the effect
+            static void StyleBar(ScottPlot.Plottables.BarPlot barPlot, double xOffset)
+            {
+                barPlot.ValueLabelStyle.FontSize = 32;
+                for (int i = 0; i < barPlot.Bars.Count; i++)
+                {
+                    var bar = barPlot.Bars[i];
+                    bar.Label = i.ToString();
+                    bar.CenterLabel = true;
+                    bar.Position = i * .5 + xOffset;
+                    bar.FillColor = bar.FillColor.WithAlpha(.9);
+                }
+            }
+
+            StyleBar(bars1, 0);
+            StyleBar(bars2, 4);
+
+            myPlot.Add.Text("Default", 0, 6);
+            myPlot.Add.Text("LabelsOnTop", 4, 6);
+
+            myPlot.HideGrid();
+        }
+    }
+
     public class BarPosition : RecipeBase
     {
         public override string Name => "Bar Positioning";

src/ScottPlot5/ScottPlot5 Cookbook/Recipes/PlotTypes/PolarAxis.cs

@@ -124,6 +124,32 @@ public override void Execute()
         }
     }
 
+    public class PolarAxisBackground : RecipeBase
+    {
+        public override string Name => "Polar Axis Background";
+        public override string Description => "The background style of polar axes may be customized";
+
+        [Test]
+        public override void Execute()
+        {
+            var polarAxis = myPlot.Add.PolarAxis();
+            polarAxis.FillColor = Colors.Blue.WithAlpha(.2);
+        }
+    }
+
+    public class PolarSpokeLength : RecipeBase
+    {
+        public override string Name => "Polar Axis Spoke Length";
+        public override string Description => "The length of spokes may be customized. " +
+            "Spoke length is expressed as a fraction of the polar axis radius.";
+
+        [Test]
+        public override void Execute()
+        {
+            myPlot.Add.PolarAxis(spokeLength: 1.3);
+        }
+    }
+
     public class PolarSpokeLabels : RecipeBase
     {
         public override string Name => "Polar Axis Spoke Labels";

src/ScottPlot5/ScottPlot5 Cookbook/Recipes/PlotTypes/Radar.cs

@@ -139,4 +139,23 @@ public override void Execute()
             radar.PolarAxis.StraightLines = true;
         }
     }
+
+    public class AxisOnTop : RecipeBase
+    {
+        public override string Name => "Axis on Top of Data";
+        public override string Description => "Radar charts can be customized so the axis is rendered on top of the data";
+
+        [Test]
+        public override void Execute()
+        {
+            double[] values = { 78, 83, 100, 76, 43 };
+            var radar = myPlot.Add.Radar(values);
+
+            // make the shape opaque
+            radar.Series[0].FillColor = Colors.RebeccaPurple;
+
+            // render the axis above the data
+            radar.IsAxisAboveData = true;
+        }
+    }
 }

src/ScottPlot5/ScottPlot5 Cookbook/Recipes/PlotTypes/Scatter.cs

@@ -438,8 +438,10 @@ public override void Execute()
             double[] ys = Generate.Sin(51);
 
             var poly = myPlot.Add.ScatterLine(xs, ys);
-
             poly.FillY = true;
+
+            // colors are placed at specific positions on the X axis
+            poly.AxisGradientDirection = AxisGradientDirection.Horizontal;
             poly.ColorPositions.Add(new(Colors.Red, 0));
             poly.ColorPositions.Add(new(Colors.Orange, 10));
             poly.ColorPositions.Add(new(Colors.Yellow, 20));
@@ -449,6 +451,29 @@ public override void Execute()
         }
     }
 
+    public class ScatterFillGradientVertical : RecipeBase
+    {
+        public override string Name => "Scatter Plot with Vertical Gradient";
+        public override string Description => "Scatter plots may be filled with vertical gradients.";
+
+        [Test]
+        public override void Execute()
+        {
+            double[] xs = Generate.Consecutive(51);
+            double[] ys = Generate.Sin(51);
+
+            var poly = myPlot.Add.ScatterLine(xs, ys);
+            poly.FillY = true;
+
+            // colors are placed at specific positions on the Y axis
+            poly.AxisGradientDirection = AxisGradientDirection.Vertical;
+            poly.ColorPositions.Add(new(Colors.Red, -1));
+            poly.ColorPositions.Add(new(Colors.Blue, 0));
+            poly.ColorPositions.Add(new(Colors.Orange, .5));
+            poly.ColorPositions.Add(new(Colors.Magenta, 1));
+        }
+    }
+
     public class ScatterScaleAndOffset : RecipeBase
     {
         public override string Name => "Scatter Scale and Offset";

src/ScottPlot5/ScottPlot5 Demos/Avalonia Demo/Demos/BackgroundImagesWindow.axaml.cs

@@ -12,7 +12,7 @@
 
 namespace Avalonia_Demo.Demos;
 
-public class BackgroundImagesDemo: IDemo
+public class BackgroundImagesDemo : IDemo
 {
     public string Title => "Background Images";
     public string Description => "Use a bitmap image for the background of the figure or data area";
@@ -39,7 +39,8 @@ public BackgroundImagesWindow()
 
     private void HandleDataContextChanged(object? sender, PropertyChangedEventArgs e)
     {
-        if (e.PropertyName == nameof(TypedDataContext.ShowFigureBackground) || e.PropertyName == nameof(TypedDataContext.ShowDataBackground) || e.PropertyName == nameof(TypedDataContext.SelectedImagePosition)) {
+        if (e.PropertyName == nameof(TypedDataContext.ShowFigureBackground) || e.PropertyName == nameof(TypedDataContext.ShowDataBackground) || e.PropertyName == nameof(TypedDataContext.SelectedImagePosition))
+        {
             ResetPlot();
         }
     }
@@ -58,8 +59,8 @@ private void ResetPlot()
         AvaPlot.Plot.Title("Plot with Image Background");
 
         // assign the bitmap image
-        AvaPlot.Plot.FigureBackground.Image =TypedDataContext.ShowFigureBackground ? SampleImages.ScottPlotLogo() : null;
-        AvaPlot.Plot.DataBackground.Image = TypedDataContext.ShowDataBackground? SampleImages.MonaLisa() : null;
+        AvaPlot.Plot.FigureBackground.Image = TypedDataContext.ShowFigureBackground ? SampleImages.ScottPlotLogo() : null;
+        AvaPlot.Plot.DataBackground.Image = TypedDataContext.ShowDataBackground ? SampleImages.MonaLisa() : null;
 
         // set the scaling mode
         AvaPlot.Plot.FigureBackground.ImagePosition = TypedDataContext.SelectedImagePosition;

src/ScottPlot5/ScottPlot5 Demos/Avalonia Demo/Demos/ScrollViewerWindow.axaml.cs

@@ -32,7 +32,7 @@ public partial class ScrollViewerWindow : Window
     public ScrollViewerWindow()
     {
         InitializeComponent();
-        
+
         DataContext = new ScrollViewerViewModel();
         TypedDataContext.PropertyChanged += HandleDataContextChanged;
 

src/ScottPlot5/ScottPlot5 Demos/Avalonia Demo/Demos/SharedAxesWindow.axaml.cs

@@ -44,7 +44,8 @@ public SharedAxesWindow()
 
     private void HandleDataContextChanged(object? sender, PropertyChangedEventArgs e)
     {
-        if (e.PropertyName == nameof(TypedDataContext.ShareX) || e.PropertyName == nameof(TypedDataContext.ShareY)) {
+        if (e.PropertyName == nameof(TypedDataContext.ShareX) || e.PropertyName == nameof(TypedDataContext.ShareY))
+        {
             UpdateLinkedPlots();
         }
     }

src/ScottPlot5/ScottPlot5 Demos/Avalonia Demo/ViewModels/Demos/BackgroundImagesViewModel.cs

@@ -13,7 +13,7 @@ public partial class BackgroundImagesViewModel : ViewModelBase
 {
     [ObservableProperty]
     private bool _showFigureBackground = true;
-    
+
     [ObservableProperty]
     private bool _showDataBackground = true;