Customize Chart Legends in Presentations Using Java

Overview

Aspose.Slides provides options for customizing chart legends in PowerPoint presentations. This article shows how to position and size a legend, set the font size for the whole legend, and apply formatting to an individual legend entry.

It also covers several related behaviors in the FAQ, including using non-overlay mode so the plot area makes room for the legend, allowing long legend labels to wrap or use line breaks, and letting legend formatting inherit from the presentation theme when explicit text and fill settings are not applied.

Legend Positioning

In order to set the legend properties. Please follow the steps below:

Create an instance of Presentation class.
Get reference of the slide.
Adding a chart on slide.
Setting the properties of legend.
Write the presentation as a PPTX file.

In the example given below, we have set the position and size for Chart legend.

// Create an instance of Presentation class
Presentation pres = new Presentation();
try {
    // Get reference of the slide
    ISlide slide = pres.getSlides().get_Item(0);
    
    // Add a clustered column chart on the slide
    IChart chart = slide.getShapes().addChart(ChartType.ClusteredColumn, 50, 50, 500, 500);
    
    // Set Legend Properties
    chart.getLegend().setX(50 / chart.getWidth());
    chart.getLegend().setY(50 / chart.getHeight());
    chart.getLegend().setWidth(100 / chart.getWidth());
    chart.getLegend().setHeight(100 / chart.getHeight());
    
    // Write presentation to disk
    pres.save("Legend_out.pptx", SaveFormat.Pptx);
} finally {
    if (pres != null) pres.dispose();
}

Set the Font Size of a Legend

The Aspose.Slides for Java lets developers allow to set font size of legend. Please follow the steps below:

Instantiate Presentation class.
Creating the default chart.
Set the Font Size.
Set minimum axis value.
Set maximum axis value.
Write presentation to disk.

// Create an instance of Presentation class
Presentation pres = new Presentation();
try {
    IChart chart = pres.getSlides().get_Item(0).getShapes().addChart(ChartType.ClusteredColumn, 50, 50, 600, 400);

    chart.getLegend().getTextFormat().getPortionFormat().setFontHeight(20);

    chart.getAxes().getVerticalAxis().setAutomaticMinValue(false);
    chart.getAxes().getVerticalAxis().setMinValue(-5);
    chart.getAxes().getVerticalAxis().setAutomaticMaxValue(false);
    chart.getAxes().getVerticalAxis().setMaxValue(10);

    pres.save("output.pptx", SaveFormat.Pptx);
} finally {
    if (pres != null) pres.dispose();
}

Set the Font Size of an Individual Legend

The Aspose.Slides for Java lets developers allow to set font size of individual legend entries. Please follow the steps below:

Instantiate Presentation class.
Creating the default chart.
Access legend entry.
Set the Font Size.
Set minimum axis value.
Set maximum axis value.
Write presentation to disk.

// Create an instance of Presentation class
Presentation pres = new Presentation();
try {
    IChart chart = pres.getSlides().get_Item(0).getShapes().addChart(ChartType.ClusteredColumn, 50, 50, 600, 400);

    IChartTextFormat tf = chart.getLegend().getEntries().get_Item(1).getTextFormat();

    tf.getPortionFormat().setFontBold(NullableBool.True);
    tf.getPortionFormat().setFontHeight(20);
    tf.getPortionFormat().setFontItalic(NullableBool.True);
    tf.getPortionFormat().getFillFormat().setFillType(FillType.Solid);
    tf.getPortionFormat().getFillFormat().getSolidFillColor().setColor(Color.BLUE);
    
    pres.save("output.pptx", SaveFormat.Pptx);
} finally {
    if (pres != null) pres.dispose();
}

FAQ

Can I enable the legend so that the chart automatically allocates space for it instead of overlaying it?

Yes. Use the non-overlay mode (setOverlay(false)); in this case, the plot area will shrink to accommodate the legend.

Can I make multi-line legend labels?

Yes. Long labels wrap automatically when space is insufficient; forced line breaks are supported via newline characters in the series name.

How do I make the legend follow the presentation theme’s color scheme?

Do not set explicit colors/fills/fonts for the legend or its text. They will then inherit from the theme and update correctly when the design changes.