Manage Chart Data Markers in Presentations Using Java

Overview

This article explains how to work with chart data markers in Aspose.Slides. It shows how to create a chart, access a series and its data points, apply picture fills to markers at the data-point level, adjust marker size, and save the updated presentation. It also notes that standard marker shapes are available through the MarkerStyleType enumeration and that marker appearance is preserved when exporting charts to raster formats or SVG.

Set Chart Marker Options

The markers can be set on chart data points inside particular series. In order to set chart marker options. Please follow the steps below:

• Instantiate Presentation class.
• Creating the default chart.
• Set the picture.
• Take first chart series.
• Add new data point.
• Write presentation to disk.

In the example given below, we have set the chart marker options on data points level.

// Creating empty presentation
Presentation pres = new Presentation();
try {
    // Access first slide
    ISlide slide = pres.getSlides().get_Item(0);
    
    // Creating the default chart
    IChart chart = slide.getShapes().addChart(ChartType.LineWithMarkers, 0, 0, 400, 400);
    
    // Getting the default chart data WorkSheet index
    int defaultWorksheetIndex = 0;
    
    // Getting the chart data WorkSheet
    IChartDataWorkbook fact = chart.getChartData().getChartDataWorkbook();
    
    // Delete demo series
    chart.getChartData().getSeries().clear();
    
    // Add new series
    chart.getChartData().getSeries().add(fact.getCell(defaultWorksheetIndex, 1, 1, "Series 1"), chart.getType());

    // Load the picture 1
    IPPImage imgx1 = pres.getImages().addImage(new FileInputStream(new File("Desert.jpg")));
    
    // Load the picture 2
    IPPImage imgx2 = pres.getImages().addImage(new FileInputStream(new File("Tulips.jpg")));
    
    // Take first chart series
    IChartSeries series = chart.getChartData().getSeries().get_Item(0);
    
    // Add new point (1:3) there.
    IChartDataPoint point = series.getDataPoints().addDataPointForLineSeries(fact.getCell(defaultWorksheetIndex, 1, 1, (double) 4.5));
    point.getMarker().getFormat().getFill().setFillType(FillType.Picture);
    point.getMarker().getFormat().getFill().getPictureFillFormat().getPicture().setImage(imgx1);
    
    point = series.getDataPoints().addDataPointForLineSeries(fact.getCell(defaultWorksheetIndex, 2, 1, (double) 2.5));
    point.getMarker().getFormat().getFill().setFillType(FillType.Picture);
    point.getMarker().getFormat().getFill().getPictureFillFormat().getPicture().setImage(imgx2);
    
    point = series.getDataPoints().addDataPointForLineSeries(fact.getCell(defaultWorksheetIndex, 3, 1, (double) 3.5));
    point.getMarker().getFormat().getFill().setFillType(FillType.Picture);
    point.getMarker().getFormat().getFill().getPictureFillFormat().getPicture().setImage(imgx1);
    
    point = series.getDataPoints().addDataPointForLineSeries(fact.getCell(defaultWorksheetIndex, 4, 1, (double) 4.5));
    point.getMarker().getFormat().getFill().setFillType(FillType.Picture);
    point.getMarker().getFormat().getFill().getPictureFillFormat().getPicture().setImage(imgx2);
    
    // Changing the chart series marker
    series.getMarker().setSize(15);
    
    // Save presentation with chart
    pres.save("ScatterChart.pptx", SaveFormat.Pptx);
} catch (IOException e) {
} finally {
    if (pres != null) pres.dispose();
}

FAQ

Which marker shapes are available out of the box?

Standard shapes are available (circle, square, diamond, triangle, etc.); the list is defined by the MarkerStyleType class. If you need a non-standard shape, use a marker with a picture fill to emulate custom visuals.

Are markers preserved when exporting a chart to an image or SVG?

Yes. When rendering charts to raster formats or saving shapes as SVG, markers retain their appearance and settings, including size, fill, and outline.