Customize Pie Charts in Presentations in .NET

What this page is about

Create and customize pie charts in .NET with Aspose.Slides. Configure secondary plots, display data labels, and apply automatic slice colors in PowerPoint.

Overview

This article explains how to work with pie charts in Aspose.Slides. It shows how to configure secondary plot options for Pie of Pie and Bar of Pie charts, and how to enable automatic slice coloring for a standard pie chart.

The examples focus on chart customization tasks such as adding a chart to a slide, adjusting series and label settings, replacing default chart data with custom categories and values, and saving the updated presentation.

Second Plot Options for Pie of Pie and Bar of Pie Charts

Aspose.Slides for .NET supports secondary plot options for Pie of Pie and Bar of Pie charts. These options control the size of the secondary plot and how data points are split between the two plots.

The following example creates a Pie of Pie chart in a new presentation and displays data point values as labels. The SecondPieSize property sets the secondary plot size to 149% of the main plot. PieSplitBy selects percentage-based splitting, and PieSplitPosition sets the threshold to 53%.

using Aspose.Slides;
using Aspose.Slides.Charts;
using Aspose.Slides.Export;

using var presentation = new Presentation();
var slide = presentation.Slides[0];

var chart = slide.Shapes.AddChart(ChartType.PieOfPie, 50, 50, 500, 400);
var series = chart.ChartData.Series[0];

// Display values and configure the secondary plot.
series.Labels.DefaultDataLabelFormat.ShowValue = true;
var seriesGroup = series.ParentSeriesGroup;
seriesGroup.SecondPieSize = 149;
seriesGroup.PieSplitBy = PieSplitType.ByPercentage;
seriesGroup.PieSplitPosition = 53;

presentation.Save("pie_of_pie.pptx", SaveFormat.Pptx);

Select Categories for the Secondary Plot

Use custom splitting when you want to group specific categories in the secondary plot regardless of their percentage values. For example, a sales report might show Online and Events together so readers can compare these two channels, even though they account for 35% and 10% of total sales.

Set PieSplitBy to PieSplitType.Custom and select the points through PieSplitCustomPoints. The collection’s Add method accepts either a zero-based index in the series or a data point object. In this example, index 1 selects Online, and the point at index 3 selects Events. Partners is also added temporarily, then excluded using Remove.

using Aspose.Slides;
using Aspose.Slides.Charts;
using Aspose.Slides.Export;

using var presentation = new Presentation();
var slide = presentation.Slides[0];

var chart = slide.Shapes.AddChart(ChartType.PieOfPie, 50, 50, 600, 200);

// Replace the default data with sales by channel.
var workbook = chart.ChartData.ChartDataWorkbook;
chart.ChartData.Series.Clear();
chart.ChartData.Categories.Clear();
var categoryNames = new[] { "Retail", "Online", "Partners", "Events" };
var values = new[] { 40, 35, 15, 10 };
var seriesNameCell = workbook.GetCell(0, 0, 1, "Sales");
var series = chart.ChartData.Series.Add(seriesNameCell, chart.Type);

for (var i = 0; i < categoryNames.Length; i++)
{
    var categoryCell = workbook.GetCell(0, i + 1, 0, categoryNames[i]);
    chart.ChartData.Categories.Add(categoryCell);

    var valueCell = workbook.GetCell(0, i + 1, 1, values[i]);
    series.DataPoints.AddDataPointForPieSeries(valueCell);
}

series.Labels.DefaultDataLabelFormat.ShowValue = true;
var seriesGroup = series.ParentSeriesGroup;
seriesGroup.PieSplitBy = PieSplitType.Custom;
seriesGroup.IsColorVaried = true;

// Select Online by its zero-based index and Events by its data point object.
seriesGroup.PieSplitCustomPoints.Add(1);
seriesGroup.PieSplitCustomPoints.Add(series.DataPoints[3]);

// Exclude Partners from the selection without deleting its source data.
seriesGroup.PieSplitCustomPoints.Add(2);
seriesGroup.PieSplitCustomPoints.Remove(series.DataPoints[2]);

presentation.Save("pie_of_pie_custom.pptx", SaveFormat.Pptx);

Online (35) and Events (10) appear as separate slices in the secondary plot. In the primary plot, they are represented by one combined slice with a value of 45, alongside Retail (40) and Partners (15). Removing Partners from the custom selection keeps it in the primary plot; it does not remove the category or its value from the chart’s source data.

The following image shows the saved presentation in PowerPoint:

Pie of Pie chart with Online and Events in the secondary plot and their combined value of 45 in the primary plot

Set Automatic Pie Chart Slice Colors

Aspose.Slides for .NET can automatically assign different colors to pie chart slices. The following example creates a pie chart with a centered title and replaces the default data with three quarterly categories and their values. The ShowValue property displays the values 20, 50, and 30 as labels, while IsColorVaried enables a distinct color for each slice.

using Aspose.Slides;
using Aspose.Slides.Charts;
using Aspose.Slides.Export;

using var presentation = new Presentation();
var slide = presentation.Slides[0];

var chart = slide.Shapes.AddChart(ChartType.Pie, 100, 100, 400, 400);

// Add a centered chart title.
chart.ChartTitle.AddTextFrameForOverriding("Sample Title");
chart.ChartTitle.TextFrameForOverriding.TextFrameFormat.CenterText = NullableBool.True;
chart.ChartTitle.Height = 20;
chart.HasTitle = true;

// Replace the default data using the first worksheet.
var workbook = chart.ChartData.ChartDataWorkbook;
var worksheetIndex = 0;
chart.ChartData.Series.Clear();
chart.ChartData.Categories.Clear();
var categoryNames = new[] { "First Qtr", "2nd Qtr", "3rd Qtr" };
var values = new[] { 20, 50, 30 };
var seriesNameCell = workbook.GetCell(worksheetIndex, 0, 1, "Series 1");
var series = chart.ChartData.Series.Add(seriesNameCell, chart.Type);

for (var i = 0; i < categoryNames.Length; i++)
{
    var categoryCell = workbook.GetCell(worksheetIndex, i + 1, 0, categoryNames[i]);
    chart.ChartData.Categories.Add(categoryCell);

    var valueCell = workbook.GetCell(worksheetIndex, i + 1, 1, values[i]);
    series.DataPoints.AddDataPointForPieSeries(valueCell);
}

// Show values and assign different colors to the slices.
series.Labels.DefaultDataLabelFormat.ShowValue = true;
series.ParentSeriesGroup.IsColorVaried = true;

presentation.Save("pie.pptx", SaveFormat.Pptx);

FAQ

Are the Pie of Pie and Bar of Pie variations supported?

Yes, the library supports a secondary plot for pie charts, including the Pie of Pie and Bar of Pie types.

Can I export just the chart as an image (for example, PNG)?

Yes, you can export the chart itself as an image (such as PNG) without exporting the entire presentation.

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