HeatmapRangeColorProvider.ApproximateColors Property

Specifies whether to approximate colors.

Namespace: DevExpress.Xpf.Charts.Heatmap

Assembly: DevExpress.Xpf.Charts.v24.1.dll

NuGet Package: DevExpress.Wpf.Charts

Declaration

C#

public bool ApproximateColors { get; set; }

VB.NET

Public Property ApproximateColors As Boolean

Property Value

Type	Description
Boolean	true if an approximation algorithm is applied to colors; otherwise, false.

Remarks

The ApproximateColors property allows you to apply smooth transition between colors:

ApproximateColors = true	ApproximateColors = false

Example

This example shows how to use arrays of string and numeric values to create a heatmap.

Follow the steps below to create a heatmap:

1. Add the HeatmapControl to the project.

2. Create a HeatmapMatrixAdapter object and assign it to the HeatmapControl.DataAdapter property.

3. Use the adapter’s XArguments and YArguments properties to populate the heatmap with x- and y-arguments that are displayed along x- and y-axes.

4. Assign a two-dimensional array of double values to the adapter’s Values property.

5. Create a HeatmapRangeColorProvider object and assign it to the HeatmapControl.ColorProvider property. The Range Color Provider paints cells based on a value range to which the cell value belongs.

6. Set the HeatmapControl.Legend property to a HeatmapLegend object to display a legend.

   Specify the color provider’s HeatmapPaletteColorProvider.LegendItemPattern property to format legend items.

7. Use the HeatmapControl.AxisX and HeatmapControl.AxisY properties to customize heatmap axes.

8. To display cell labels, initialize the HeatmapControl.Label property with a HeatmapLabel object.

View Example

XAML

<dx:ThemedWindow
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    xmlns:dx="http://schemas.devexpress.com/winfx/2008/xaml/core"
    xmlns:dxh="http://schemas.devexpress.com/winfx/2008/xaml/heatmap" 
    xmlns:dxc="http://schemas.devexpress.com/winfx/2008/xaml/charts"
    xmlns:local="clr-namespace:HeatmapMatrixData"
    x:Class="HeatmapMatrixData.MainWindow"
    Title="Heatmap" Height="500" Width="800">
    <Grid>
        <dxh:HeatmapControl>
            <dxh:HeatmapControl.DataContext>
                <local:MatrixHeatmapViewModel/>
            </dxh:HeatmapControl.DataContext>
            <dxh:HeatmapControl.DataAdapter>
                <dxh:HeatmapMatrixAdapter XArguments="{Binding XArguments}" 
                                          YArguments="{Binding YArguments}" 
                                          Values="{Binding Values}"/>
            </dxh:HeatmapControl.DataAdapter>
            <dxh:HeatmapControl.Titles>
                <dxc:Title Content="Sales by Categories" HorizontalAlignment="Center"/>
            </dxh:HeatmapControl.Titles>
            <dxh:HeatmapControl.ColorProvider>
                <dxh:HeatmapRangeColorProvider ApproximateColors="True" 
                                               LegendItemPattern="${V1}-{V2}K">
                    <dxh:HeatmapRangeColorProvider.Palette>
                        <dxc:CustomPalette>
                            <dxc:CustomPalette.Colors>
                                <Color>White</Color>
                                <Color>SkyBlue</Color>
                                <Color>DarkBlue</Color>
                            </dxc:CustomPalette.Colors>
                        </dxc:CustomPalette>
                    </dxh:HeatmapRangeColorProvider.Palette>
                    <dxh:HeatmapRangeColorProvider.RangeStops>
                        <dxh:HeatmapRangeStop Value="0" Type="Percentage"/>
                        <dxh:HeatmapRangeStop Value="200"/>
                        <dxh:HeatmapRangeStop Value="400"/>
                        <dxh:HeatmapRangeStop Value="600"/>
                        <dxh:HeatmapRangeStop Value="800"/>
                        <dxh:HeatmapRangeStop Value="1" Type="Percentage"/>
                    </dxh:HeatmapRangeColorProvider.RangeStops>
                </dxh:HeatmapRangeColorProvider>
            </dxh:HeatmapControl.ColorProvider>
            <dxh:HeatmapControl.Legend>
                <dxh:HeatmapLegend Margin="0, 0, 4, 10">
                    <dxh:HeatmapLegend.Title>
                        <dxc:LegendTitle Content="Revenue"/>
                    </dxh:HeatmapLegend.Title>
                </dxh:HeatmapLegend>
            </dxh:HeatmapControl.Legend>
            <dxh:HeatmapControl.AxisX>
                <dxh:HeatmapAxis>
                    <dxh:HeatmapAxis.Title>
                        <dxc:AxisTitle Content="Region"/>
                    </dxh:HeatmapAxis.Title>
                </dxh:HeatmapAxis>
            </dxh:HeatmapControl.AxisX>
            <dxh:HeatmapControl.AxisY>
                <dxh:HeatmapAxis Reverse="True">
                    <dxh:HeatmapAxis.Title>
                        <dxc:AxisTitle Content="Category"/>
                    </dxh:HeatmapAxis.Title>
                </dxh:HeatmapAxis>
            </dxh:HeatmapControl.AxisY>
            <dxh:HeatmapControl.Label>
                <dxh:HeatmapLabel Foreground="Black" 
                                  Background="#70ffffff" 
                                  Padding="2"/>
            </dxh:HeatmapControl.Label>
        </dxh:HeatmapControl>
    </Grid>
</dx:ThemedWindow>

C#

using DevExpress.Xpf.Core;

namespace HeatmapMatrixData {
    public partial class MainWindow : ThemedWindow {
        public MainWindow() {
            InitializeComponent();
        }
    }
    public class MatrixHeatmapViewModel {
        public string[] XArguments { get; set; }
        public string[] YArguments { get; set; }
        public double[,] Values { get; set; }
        public MatrixHeatmapViewModel() {
            XArguments = new string[] { "North", "South", "West", "East", "Central" };
            YArguments = new string[] { "Accessories", "Bikes", "Clothing", "Components" };
            Values = new double[,] {
               { 214.3, 530.1, 630.2, 854.4, 313.4 },
               { 321.3, 514.4, 281.3, 533.4, 541.9 },
               { 604.3, 429.1, 632.6, 438.4, 265.4 },
               { 485.3, 544.7, 740.3, 661.4, 516.6 }
            };
        }
    }
}

VB.NET

Imports DevExpress.Xpf.Core

Namespace HeatmapMatrixData

    Public Partial Class MainWindow
        Inherits ThemedWindow

        Public Sub New()
            Me.InitializeComponent()
        End Sub
    End Class

    Public Class MatrixHeatmapViewModel

        Public Property XArguments As String()

        Public Property YArguments As String()

        Public Property Values As Double(,)

        Public Sub New()
            XArguments = New String() {"North", "South", "West", "East", "Central"}
            YArguments = New String() {"Accessories", "Bikes", "Clothing", "Components"}
            Values = New Double(,) {{214.3, 530.1, 630.2, 854.4, 313.4}, {321.3, 514.4, 281.3, 533.4, 541.9}, {604.3, 429.1, 632.6, 438.4, 265.4}, {485.3, 544.7, 740.3, 661.4, 516.6}}
        End Sub
    End Class
End Namespace