Custom Slice or Sector Colors in Pie Chart with JavaScript via C++

This article explains how to add custom colors to pie chart slices/sectors. By default, pie charts use the Microsoft Excel default template. To use other colors, redefine the colors in the chart.

To set a custom color for a pie chart’s individual slices or sectors:

Access the Series object’s ChartPoint.
Assign the color of your choice using the ChartPoint.foregroundColor property.

This article also explains how to:

A chart’s category data.
A chart title linked to a cell.
The chart title font settings.
The position of the legend.

ChartPoint.foregroundColor is not specific to pie charts but it can be used for all types of charts.

<!DOCTYPE html>
<html>
    <head>
        <title>Aspose.Cells Example</title>
    </head>
    <body>
        <h1>Aspose.Cells Pie Chart Example</h1>
        <input type="file" id="fileInput" accept=".xls,.xlsx,.csv" />
        <button id="runExample">Run Example</button>
        <a id="downloadLink" style="display: none;">Download Result</a>
        <div id="result"></div>
    </body>

    <script src="aspose.cells.js.min.js"></script>
    <script type="text/javascript">
        const { Workbook, SaveFormat } = AsposeCells;
        
        AsposeCells.onReady({
            license: "/lic/aspose.cells.enc",
            fontPath: "/fonts/",
            fontList: [
                "arial.ttf",
                "NotoSansSC-Regular.ttf"
            ]
        }).then(() => {
            console.log("Aspose.Cells initialized");
        });

        document.getElementById('runExample').addEventListener('click', async () => {
            const fileInput = document.getElementById('fileInput');
            if (!fileInput.files.length) {
                document.getElementById('result').innerHTML = '<p style="color: red;">Please select an Excel file.</p>';
                return;
            }

            const file = fileInput.files[0];
            const arrayBuffer = await file.arrayBuffer();

            // Instantiating a Workbook object using the uploaded file
            const workbook = new Workbook(new Uint8Array(arrayBuffer));

            // Access the first worksheet.
            const worksheet = workbook.worksheets.get(0);

            // Put the sample values used in a pie chart
            worksheet.cells.get("C3").value = "India";
            worksheet.cells.get("C4").value = "China";
            worksheet.cells.get("C5").value = "United States";
            worksheet.cells.get("C6").value = "Russia";
            worksheet.cells.get("C7").value = "United Kingdom";
            worksheet.cells.get("C8").value = "Others";

            // Put the sample values used in a pie chart
            worksheet.cells.get("D2").value = "% of world population";
            worksheet.cells.get("D3").value = 25;
            worksheet.cells.get("D4").value = 30;
            worksheet.cells.get("D5").value = 10;
            worksheet.cells.get("D6").value = 13;
            worksheet.cells.get("D7").value = 9;
            worksheet.cells.get("D8").value = 13;

            // Create a pie chart with desired length and width
            const pieIdx = worksheet.charts.add(AsposeCells.ChartType.Pie, 1, 6, 15, 14);

            // Access the pie chart
            const pie = worksheet.charts.get(pieIdx);

            // Set the pie chart series
            pie.nSeries.add("D3:D8", true);

            // Set the category data
            pie.nSeries.categoryData = "=Sheet1!$C$3:$C$8";

            // Set the chart title that is linked to cell D2
            pie.title.linkedSource = "D2";

            // Set the legend position at the bottom.
            pie.legend.position = AsposeCells.LegendPositionType.Bottom;

            // Set the chart title's font name and color
            pie.title.font.name = "Calibri";
            pie.title.font.size = 18;

            // Access the chart series
            const srs = pie.nSeries.get(0);

            // Color the individual points with custom colors
            srs.points.get(0).area.foregroundColor = new AsposeCells.Color(0, 246, 22, 219);
            srs.points.get(1).area.foregroundColor = new AsposeCells.Color(0, 51, 34, 84);
            srs.points.get(2).area.foregroundColor = new AsposeCells.Color(0, 46, 74, 44);
            srs.points.get(3).area.foregroundColor = new AsposeCells.Color(0, 19, 99, 44);
            srs.points.get(4).area.foregroundColor = new AsposeCells.Color(0, 208, 223, 7);
            srs.points.get(5).area.foregroundColor = new AsposeCells.Color(0, 222, 69, 8);

            // Autofit all columns
            worksheet.autoFitColumns();

            // Saving the modified Excel file and offering download
            const outputData = workbook.save(SaveFormat.Xlsx);
            const blob = new Blob([outputData]);
            const downloadLink = document.getElementById('downloadLink');
            downloadLink.href = URL.createObjectURL(blob);
            downloadLink.download = 'output.out.xlsx';
            downloadLink.style.display = 'block';
            downloadLink.textContent = 'Download Excel File';

            document.getElementById('result').innerHTML = '<p style="color: green;">Operation completed successfully! Click the download link to get the modified file.</p>';
        });
    </script>
</html>

Find if Data Points are in the Second Pie or Bar on a Pie of Pie or Bar of Pie Chart with JavaScript via C++