使用 JavaScript 通过 C++ 处理图像
Contents
[
Hide
]
Aspose.Cells允许您从工作簿导出工作表并将其转换为不同的格式。本文解释了如何将工作表转换为不同的格式。
将工作簿转换为TIFF
一个 Excel 文件可以包含多个工作表和多页。WorkbookRender 允许你将 Excel 转换为多页 TIFF。此外，你还可以控制 TIFF 的多个选项，比如 ImageOrPrintOptions.tiffCompression、ImageOrPrintOptions.tiffColorDepth、分辨率(ImageOrPrintOptions.horizontalResolution、ImageOrPrintOptions.verticalResolution)。
以下代码片段显示了如何将Excel转换为具有多个页面的TIFF。源Excel文件和生成的TIFF图像附在此供参考。
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Example</title>
</head>
<body>
<h1>Workbook to TIFF (Multiple Pages) 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, ImageOrPrintOptions, ImageType, TiffCompression, WorkbookRender } = 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();
// Instantiate workbook from uploaded file
const wb = new Workbook(new Uint8Array(arrayBuffer));
// Configure image/print options
const imgOptions = new ImageOrPrintOptions();
imgOptions.imageType = ImageType.Tiff;
imgOptions.horizontalResolution = 200;
imgOptions.verticalResolution = 200;
imgOptions.tiffCompression = TiffCompression.CompressionLZW;
// Render workbook to image (TIFF)
const workbookRender = new WorkbookRender(wb, imgOptions);
// Obtain image data (multi-page TIFF)
const outputData = workbookRender.toImage();
const blob = new Blob([outputData], { type: "image/tiff" });
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'workbook-to-tiff-with-mulitiple-pages.tiff';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download TIFF File';
document.getElementById('result').innerHTML = '<p style="color: green;">TIFF created successfully! Click the download link to get the file.</p>';
});
</script>
</html>
将工作表转换为图像
工作表包含您想要分析的数据。例如，工作表可以包含参数、总计、百分比、异常和计算。
作为开发者，你可能需要将工作表呈现为图片。例如，可以将工作表作为图片在应用程序或网页中使用。你可能希望将图片插入到 Microsoft Word 文档、PDF 文件、PowerPoint 演示文稿或其他类型的文档中。简而言之，你希望将工作表渲染成图片，以便在其他地方使用。
SheetRender ImageOrPrintOptions WorkbookRender
SheetRender 类代表一个要渲染为图片的工作表。它有一个重载方法 SheetRender.toImage(number, string)，可以将工作表转换为具有不同属性或选项的图片文件。它返回一个 Buffer 对象，你可以将图片文件保存到磁盘或流中。支持多种图片格式，例如 BMP、PNG、GIF、JPG、JPEG、TIFF、EMF。
以下代码片段显示了如何将Excel文件中的工作表转换为图像文件。
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Example - Convert Worksheet To Images By Page</title>
</head>
<body>
<h1>Convert Worksheet To Images By Page</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, ImageOrPrintOptions, SheetRender, ImageType, Utils } = 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');
const resultDiv = document.getElementById('result');
resultDiv.innerHTML = '';
if (!fileInput.files.length) {
resultDiv.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 from the uploaded file
const workbook = new Workbook(new Uint8Array(arrayBuffer));
// Accessing the first worksheet in the Excel file
const sheet = workbook.worksheets.get(0);
// Preparing image/print options
const options = new ImageOrPrintOptions();
options.horizontalResolution = 200;
options.verticalResolution = 200;
options.imageType = ImageType.Tiff;
// Sheet to Image By Page conversion
const sr = new SheetRender(sheet, options);
const pageCount = sr.pageCount;
if (pageCount === 0) {
resultDiv.innerHTML = '<p style="color: red;">No pages found to render.</p>';
return;
}
const linksContainer = document.createElement('div');
linksContainer.innerHTML = '<p style="color: green;">Conversion completed. Download the generated images below:</p>';
for (let j = 0; j < pageCount; j++)
{
// sr.toImage(pageIndex) returns image bytes in browser build
const imageData = sr.toImage(j);
const blob = new Blob([imageData], { type: 'image/tiff' });
const url = URL.createObjectURL(blob);
const link = document.createElement('a');
link.href = url;
link.download = "outputConvertWorksheetToImageByPage_" + (j + 1) + ".tif";
link.textContent = "Download Image Page " + (j + 1);
link.style.display = 'block';
linksContainer.appendChild(link);
}
resultDiv.appendChild(linksContainer);
});
</script>
</html>
目前，将工作表转换为图像的API不支持3D气泡图。
将工作表转换为SVG
SVG代表可缩放矢量图形。SVG是基于XML标准的二维矢量图形规范。自1999年以来，它一直是由万维网联盟（W3C）开发的开放标准。
自版本7.1.0起，通过C++的Aspose.Cells for JavaScript能够将工作表转换为SVG图像。以下代码片段展示了如何将Excel文件中的工作表转换为SVG图像文件。
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Example</title>
</head>
<body>
<h1>Convert Worksheet to SVG 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, SheetType } = 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 () => {
// Instantiate a workbook
const workbook = new Workbook();
// Put sample text in the first cell of the first worksheet in the newly created workbook
workbook.worksheets.get(0).cells.get("A1").putValue("DEMO TEXT ON SHEET1");
// Add second worksheet in the workbook
workbook.worksheets.add(SheetType.Worksheet);
// Set text in the first cell of the second sheet
workbook.worksheets.get(1).cells.get("A1").putValue("DEMO TEXT ON SHEET2");
// Set currently active sheet index to 1 i.e. Sheet2
workbook.worksheets.activeSheetIndex = 1;
// Save workbook to SVG. It shall render the active sheet only to SVG
const outputData = workbook.save(SaveFormat.Svg);
const blob = new Blob([outputData]);
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'ConvertWorksheetToSVG_out.svg';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download SVG File';
document.getElementById('result').innerHTML = '<p style="color: green;">SVG generated successfully! Click the download link to get the file.</p>';
});
</script>
</html>