使用 Node.js 通过 C++ 创建带引线的饼图
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本文讲解了如何使用Aspose.Cells for Node.js via C++ API 从头创建带引线的饼图。在 Excel 中，“显示引线”选项默认开启，因此在创建饼图时，引线会自动显示。而在使用 Aspose.Cells API 创建类似图表时，必须明确设置 Series.getHasLeaderLines() 属性。
为了演示如何使用Aspose.Cells for Node.js via C++ API创建带引线的饼图，我们将首先创建一个新的 Workbook 并输入一些作为系列数据源的数据。一旦数据准备完毕，我们将在图表集合中添加一个类型为 ChartType.Pie 的 Chart，并设置其不同方面以获得预期的图表效果。
const path = require("path");
const AsposeCells = require("aspose.cells.node");
// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "sample.xlsx");
// Loads the workbook which contains hidden external links
const workbook = new AsposeCells.Workbook(filePath);
// Access the first worksheet
const worksheet = workbook.getWorksheets().get(0);
// Add two columns of data
worksheet.getCells().get("A1").putValue("Retail");
worksheet.getCells().get("A2").putValue("Services");
worksheet.getCells().get("A3").putValue("Info & Communication");
worksheet.getCells().get("A4").putValue("Transport Equip");
worksheet.getCells().get("A5").putValue("Construction");
worksheet.getCells().get("A6").putValue("Other Products");
worksheet.getCells().get("A7").putValue("Wholesale");
worksheet.getCells().get("A8").putValue("Land Transport");
worksheet.getCells().get("A9").putValue("Air Transport");
worksheet.getCells().get("A10").putValue("Electric Appliances");
worksheet.getCells().get("A11").putValue("Securities");
worksheet.getCells().get("A12").putValue("Textiles & Apparel");
worksheet.getCells().get("A13").putValue("Machinery");
worksheet.getCells().get("A14").putValue("Metal Products");
worksheet.getCells().get("A15").putValue("Cash");
worksheet.getCells().get("A16").putValue("Banks");
worksheet.getCells().get("B1").putValue(10.4);
worksheet.getCells().get("B2").putValue(5.2);
worksheet.getCells().get("B3").putValue(6.4);
worksheet.getCells().get("B4").putValue(10.4);
worksheet.getCells().get("B5").putValue(7.9);
worksheet.getCells().get("B6").putValue(4.1);
worksheet.getCells().get("B7").putValue(3.5);
worksheet.getCells().get("B8").putValue(5.7);
worksheet.getCells().get("B9").putValue(3);
worksheet.getCells().get("B10").putValue(14.7);
worksheet.getCells().get("B11").putValue(3.6);
worksheet.getCells().get("B12").putValue(2.8);
worksheet.getCells().get("B13").putValue(7.8);
worksheet.getCells().get("B14").putValue(2.4);
worksheet.getCells().get("B15").putValue(1.8);
worksheet.getCells().get("B16").putValue(10.1);
// Create a pie chart and add it to the collection of charts
const id = worksheet.getCharts().add(AsposeCells.ChartType.Pie, 3, 3, 23, 13);
// Access newly created Chart instance
const chart = worksheet.getCharts().get(id);
// Set series data range
chart.getNSeries().add("B1:B16", true);
// Set category data range
chart.getNSeries().setCategoryData("A1:A16");
// Turn off legend
chart.setShowLegend(false);
// Access data labels
const dataLabels = chart.getNSeries().get(0).getDataLabels();
// Turn on category names
dataLabels.setShowCategoryName(true);
// Turn on percentage format
dataLabels.setShowPercentage(true);
// Set position
dataLabels.setPosition(AsposeCells.LabelPositionType.OutsideEnd);
// Set separator
dataLabels.setSeparatorType(AsposeCells.DataLabelsSeparatorType.Comma);
到目前为止，我们已经创建了饼图并设置了其不同的方面。现在我们将为图表打开引导线。请注意，为了显示引导线，我们必须稍微移动数据标签的位置。
以下代码片段打开了引导线，刷新了图表，然后计算数据标签的位置，以相应地移动它们。
const AsposeCells = require("aspose.cells.node");
const path = require("path");
// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "sample.xlsx");
// Loads the workbook which contains hidden external links
const workbook = new AsposeCells.Workbook(filePath);
// Access the first worksheet
const worksheet = workbook.getWorksheets().get(0);
// Add two columns of data
worksheet.getCells().get("A1").putValue("Retail");
worksheet.getCells().get("A2").putValue("Services");
worksheet.getCells().get("A3").putValue("Info & Communication");
worksheet.getCells().get("A4").putValue("Transport Equip");
worksheet.getCells().get("A5").putValue("Construction");
worksheet.getCells().get("A6").putValue("Other Products");
worksheet.getCells().get("A7").putValue("Wholesale");
worksheet.getCells().get("A8").putValue("Land Transport");
worksheet.getCells().get("A9").putValue("Air Transport");
worksheet.getCells().get("A10").putValue("Electric Appliances");
worksheet.getCells().get("A11").putValue("Securities");
worksheet.getCells().get("A12").putValue("Textiles & Apparel");
worksheet.getCells().get("A13").putValue("Machinery");
worksheet.getCells().get("A14").putValue("Metal Products");
worksheet.getCells().get("A15").putValue("Cash");
worksheet.getCells().get("A16").putValue("Banks");
worksheet.getCells().get("B1").putValue(10.4);
worksheet.getCells().get("B2").putValue(5.2);
worksheet.getCells().get("B3").putValue(6.4);
worksheet.getCells().get("B4").putValue(10.4);
worksheet.getCells().get("B5").putValue(7.9);
worksheet.getCells().get("B6").putValue(4.1);
worksheet.getCells().get("B7").putValue(3.5);
worksheet.getCells().get("B8").putValue(5.7);
worksheet.getCells().get("B9").putValue(3);
worksheet.getCells().get("B10").putValue(14.7);
worksheet.getCells().get("B11").putValue(3.6);
worksheet.getCells().get("B12").putValue(2.8);
worksheet.getCells().get("B13").putValue(7.8);
worksheet.getCells().get("B14").putValue(2.4);
worksheet.getCells().get("B15").putValue(1.8);
worksheet.getCells().get("B16").putValue(10.1);
// Create a pie chart and add it to the collection of charts
const id = worksheet.getCharts().add(AsposeCells.ChartType.Pie, 3, 3, 23, 13);
// Access newly created Chart instance
const chart = worksheet.getCharts().get(id);
// Set series data range
chart.getNSeries().add("B1:B16", true);
// Set category data range
chart.getNSeries().setCategoryData("A1:A16");
// Turn off legend
chart.setShowLegend(false);
// Access data labels
const dataLabels = chart.getNSeries().get(0).getDataLabels();
// Turn on category names
dataLabels.setShowCategoryName(true);
// Turn on percentage format
dataLabels.setShowPercentage(true);
// Set position
dataLabels.setPosition(AsposeCells.LabelPositionType.OutsideEnd);
// Set separator
dataLabels.setSeparatorType(AsposeCells.DataLabelsSeparatorType.Comma);
// Turn on leader lines
chart.getNSeries().get(0).setHasLeaderLines(true);
// Calculate chart
chart.calculate();
// You need to move DataLabels a little leftward or rightward depending on their position to show leader lines
const DELTA = 100;
for (let i = 0; i < chart.getNSeries().get(0).getPoints().getCount(); i++) {
let X = chart.getNSeries().get(0).getPoints().get(i).getDataLabels().getX();
// If it is greater than 2000, then move the X position a little right otherwise move the X position a little left
if (X > 2000)
chart.getNSeries().get(0).getPoints().get(i).getDataLabels().setX(X + DELTA);
else
chart.getNSeries().get(0).getPoints().get(i).getDataLabels().setX(X - DELTA);
}
最后，以下代码将图表保存为图像格式，将工作簿保存为XLSX格式。
const path = require("path");
const AsposeCells = require("aspose.cells.node");
// The path to the documents directory.
const dataDir = path.join(__dirname, "data");
const filePath = path.join(dataDir, "sample.xlsx");
// Create an instance of Workbook in XLSX format
const workbook = new AsposeCells.Workbook(AsposeCells.FileFormatType.Xlsx);
// Access the first worksheet
const worksheet = workbook.getWorksheets().get(0);
// Add two columns of data
worksheet.getCells().get("A1").putValue("Retail");
worksheet.getCells().get("A2").putValue("Services");
worksheet.getCells().get("A3").putValue("Info & Communication");
worksheet.getCells().get("A4").putValue("Transport Equip");
worksheet.getCells().get("A5").putValue("Construction");
worksheet.getCells().get("A6").putValue("Other Products");
worksheet.getCells().get("A7").putValue("Wholesale");
worksheet.getCells().get("A8").putValue("Land Transport");
worksheet.getCells().get("A9").putValue("Air Transport");
worksheet.getCells().get("A10").putValue("Electric Appliances");
worksheet.getCells().get("A11").putValue("Securities");
worksheet.getCells().get("A12").putValue("Textiles & Apparel");
worksheet.getCells().get("A13").putValue("Machinery");
worksheet.getCells().get("A14").putValue("Metal Products");
worksheet.getCells().get("A15").putValue("Cash");
worksheet.getCells().get("A16").putValue("Banks");
worksheet.getCells().get("B1").putValue(10.4);
worksheet.getCells().get("B2").putValue(5.2);
worksheet.getCells().get("B3").putValue(6.4);
worksheet.getCells().get("B4").putValue(10.4);
worksheet.getCells().get("B5").putValue(7.9);
worksheet.getCells().get("B6").putValue(4.1);
worksheet.getCells().get("B7").putValue(3.5);
worksheet.getCells().get("B8").putValue(5.7);
worksheet.getCells().get("B9").putValue(3);
worksheet.getCells().get("B10").putValue(14.7);
worksheet.getCells().get("B11").putValue(3.6);
worksheet.getCells().get("B12").putValue(2.8);
worksheet.getCells().get("B13").putValue(7.8);
worksheet.getCells().get("B14").putValue(2.4);
worksheet.getCells().get("B15").putValue(1.8);
worksheet.getCells().get("B16").putValue(10.1);
// Create a pie chart and add it to the collection of charts
const id = worksheet.getCharts().add(AsposeCells.ChartType.Pie, 3, 3, 23, 13);
// Access newly created Chart instance
const chart = worksheet.getCharts().get(id);
// Set series data range
chart.getNSeries().add("B1:B16", true);
// Set category data range
chart.getNSeries().setCategoryData("A1:A16");
// Turn off legend
chart.setShowLegend(false);
// Access data labels
const dataLabels = chart.getNSeries().get(0).getDataLabels();
// Turn on category names
dataLabels.setShowCategoryName(true);
// Turn on percentage format
dataLabels.setShowPercentage(true);
// Set position
dataLabels.setPosition(AsposeCells.LabelPositionType.OutsideEnd);
// Set separator
dataLabels.setSeparatorType(AsposeCells.DataLabelsSeparatorType.Comma);
// In order to save the chart image, create an instance of ImageOrPrintOptions
const anOption = new AsposeCells.ImageOrPrintOptions();
// Set image format
anOption.setImageType(AsposeCells.ImageType.Png);
// Set resolution
anOption.setHorizontalResolution(200);
anOption.setVerticalResolution(200);
// Render chart to image
chart.toImage(path.join(dataDir, "output_out.png"), anOption);
// Save the workbook to see chart inside the Excel
workbook.save(path.join(dataDir, "output_out.xlsx"));
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