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WPF Heatmap Peak Detector
// WPF Chart Examples
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Demonstrates how to create a UniformHeatmap and use Automatic Peak Detection to highlight peaks on dense heatmaps. This is useful when heatmap is bigger than a screen resolution. In this case peaks may be lost because of heatmap compression. Setting the AutoPeakDetection property on a FastUniformHeatmapRenderableSeries turns on a peak detection algorithm to avoid this.
Documentation links:
– Heatmap API Documentation
– UniformHeatmapDataSeries class
– RenderableSeries API.
// Source Code
The C#/WPF source code for the WPF Heatmap Peak Detector example is included below (Scroll down!).
Did you know you can also view the source code from one of the following sources as well?
- Clone the SciChart.WPF.Examples from Github.
- Or, view source in the SciChart WPF Examples suite.
- Also the SciChart WPF Trial contains the full source for the examples (link below).
The SciChart Examples source code is available on Github and viewable in-app for some platforms
// UniformHeatmapPeakDetection.xaml
<UserControl x:Class="SciChart.Examples.Examples.HeatmapChartTypes.UniformHeatmapPeakDetection.UniformHeatmapPeakDetection"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
xmlns:ext="http://schemas.abtsoftware.co.uk/scichart/exampleExternals"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:s="http://schemas.abtsoftware.co.uk/scichart"
mc:Ignorable="d"
d:DesignHeight="450"
d:DesignWidth="800">
<UserControl.Resources>
<s:GradientStopsToLinearGradientBrushConverter x:Key="ColorsToLinearGradientBrushConverter"/>
</UserControl.Resources>
<Grid>
<Grid.RowDefinitions>
<RowDefinition Height="Auto"/>
<RowDefinition Height="*"/>
</Grid.RowDefinitions>
<Grid.ColumnDefinitions>
<ColumnDefinition Width="Auto"/>
<ColumnDefinition Width="*"/>
</Grid.ColumnDefinitions>
<Border Grid.RowSpan="2"
Background="#232426"
BorderBrush="#323539"
BorderThickness="0,0,2,0">
<StackPanel>
<ToggleButton x:Name="RubberBandToggle"
HorizontalAlignment="Left"
Content="Zoom"
IsChecked="True"
Style="{StaticResource ZoomButtonStyle}"
ToolTipService.ToolTip="Toggle Rubber-Band Zoom"
s:ToggleButtonExtensions.GroupName="ZoomPanSelectionGroup"/>
<ToggleButton x:Name="ZoomPanToggle"
HorizontalAlignment="Left"
Content="Pan"
IsChecked="False"
Style="{StaticResource PanButtonStyle}"
ToolTipService.ToolTip="Toggle Zoom-Pan"
s:ToggleButtonExtensions.GroupName="ZoomPanSelectionGroup"/>
<Button HorizontalAlignment="Left"
Command="{Binding AnimateZoomExtentsCommand, Source={x:Reference SciChartSurface}}"
Content="Zoom Extents"
Style="{StaticResource ZoomExtentsButtonStyle}"
ToolTipService.ToolTip="Zoom to Extents"/>
<ext:FlyoutSeparator/>
<ToggleButton x:Name="PeakDetectorToggle"
HorizontalAlignment="Left"
Content="PD"
IsChecked="True"
Style="{StaticResource DefaultToggleButtonStyle}"
ToolTipService.ToolTip="Toggle Auto Peak Detection"/>
</StackPanel>
</Border>
<s:SciChartSurface x:Name="SciChartSurface" Grid.Row="1" Grid.Column="1">
<s:SciChartSurface.RenderableSeries>
<s:FastUniformHeatmapRenderableSeries x:Name="HeatmapRenderableSeries">
<s:FastUniformHeatmapRenderableSeries.Style>
<Style TargetType="{x:Type s:FastUniformHeatmapRenderableSeries}">
<Setter Property="AutoPeakDetection" Value="{Binding IsChecked, Source={x:Reference PeakDetectorToggle}}" />
<Setter Property="ColorMap">
<Setter.Value>
<s:HeatmapColorPalette Minimum="-70" Maximum="0">
<s:HeatmapColorPalette.GradientStops>
<GradientStop Offset="0" Color="Transparent" />
<GradientStop Offset="0.0001" Color="DarkBlue" />
<GradientStop Offset="0.2" Color="CornflowerBlue" />
<GradientStop Offset="0.4" Color="DarkGreen" />
<GradientStop Offset="0.6" Color="Chartreuse" />
<GradientStop Offset="0.8" Color="Yellow" />
<GradientStop Offset="1" Color="Red" />
</s:HeatmapColorPalette.GradientStops>
</s:HeatmapColorPalette>
</Setter.Value>
</Setter>
</Style>
</s:FastUniformHeatmapRenderableSeries.Style>
</s:FastUniformHeatmapRenderableSeries>
</s:SciChartSurface.RenderableSeries>
<s:SciChartSurface.XAxis>
<s:NumericAxis AutoRange="Once" />
</s:SciChartSurface.XAxis>
<s:SciChartSurface.YAxis>
<s:NumericAxis AutoRange="Once"/>
</s:SciChartSurface.YAxis>
<s:SciChartSurface.ChartModifier>
<s:ModifierGroup>
<s:ZoomExtentsModifier IsEnabled="True"/>
<s:ZoomPanModifier IsEnabled="{Binding IsChecked, Source={x:Reference ZoomPanToggle}}"/>
<s:RubberBandXyZoomModifier IsEnabled="{Binding IsChecked, Source={x:Reference RubberBandToggle}}"/>
</s:ModifierGroup>
</s:SciChartSurface.ChartModifier>
</s:SciChartSurface>
<s:HeatmapColorMap Grid.Row="0"
Grid.Column="1"
HorizontalAlignment="Stretch"
VerticalAlignment="Top"
BorderThickness="0"
Background="Transparent"
ColorMap="{Binding ColorMap.GradientStops, Source={x:Reference HeatmapRenderableSeries}, Converter={StaticResource ColorsToLinearGradientBrushConverter}}"
Maximum="{Binding ColorMap.Maximum, Source={x:Reference HeatmapRenderableSeries}}"
Minimum="{Binding ColorMap.Minimum, Source={x:Reference HeatmapRenderableSeries}}"
Orientation="Horizontal"
EnableAxisDrag="True"
TextFormatting="0">
<s:HeatmapColorMap.AxisStyle>
<Style TargetType="s:AxisBase">
<Setter Property="Margin" Value="0,-15,0,0"/>
<Setter Property="DrawMajorBands" Value="False"/>
<Setter Property="DrawMinorTicks" Value="False"/>
<Setter Property="DrawMajorGridLines" Value="False"/>
<Setter Property="DrawMinorGridLines" Value="False"/>
</Style>
</s:HeatmapColorMap.AxisStyle>
</s:HeatmapColorMap>
</Grid>
</UserControl>// UniformHeatmapPeakDetection.xaml.cs
using SciChart.Charting.Model.DataSeries.Heatmap2DArrayDataSeries;
using SciChart.Examples.ExternalDependencies.Data;
using System;
using System.Windows.Controls;
namespace SciChart.Examples.Examples.HeatmapChartTypes.UniformHeatmapPeakDetection
{
public partial class UniformHeatmapPeakDetection : UserControl
{
public UniformHeatmapPeakDetection()
{
InitializeComponent();
var buffer = GetSpectrogramBuffer();
HeatmapRenderableSeries.DataSeries = new UniformHeatmapDataSeries<int, int, double>(buffer, 0, 1, 0, 1);
}
private double[,] GetSpectrogramBuffer()
{
const int yCount = 100;
const int xCount = 4_096;
var spectrogramBuffer = new double[yCount, xCount];
var random = new Random();
var transform = new FFT2();
transform.init(12);
var re = new double[xCount];
var im = new double[xCount];
for (int y = 0; y < yCount; y++)
{
for (int i = 0; i < xCount; i++)
{
re[i] = 2d * Math.Sin(2 * Math.PI * i / 20) +
5 * Math.Sin(2 * Math.PI * i / 10) -
2d * random.NextDouble();
im[i] = -10;
}
transform.run(re, im);
for (int i = 0; i < xCount; i++)
{
var mag = Math.Sqrt(re[i] * re[i] + im[i] * im[i]);
im[i] = i;
spectrogramBuffer[y, i] = 20 * Math.Log10(mag / xCount);
}
}
return spectrogramBuffer;
}
}
}