工作表转图片——设置渲染图像的像素格式（JavaScript通过C++）
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有时，当将工作表渲染为图像格式时，您可能需要指定像素格式。默认情况下，Aspose.Cells使用32位每像素。Aspose.Cells允许您使用渲染图像的选项自定义像素格式（位深度）。
请参阅下面的示例代码，演示了如何在渲染工作表的图像时设置所需的像素格式。
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Example - Set Pixel Format Rendered Image</title>
</head>
<body>
<h1>Set Pixel Format Rendered Image Example</h1>
<input type="file" id="fileInput" accept=".xls,.xlsx,.xlsm,.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, ColorDepth, ImageType } = 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 from the uploaded file
const workbook = new Workbook(new Uint8Array(arrayBuffer));
// Accessing the first worksheet in the Excel file
const worksheet = workbook.worksheets.get(0);
// Set the ImageOrPrintOptions with desired color depth (24 bits per pixel) and image format type
const opts = new ImageOrPrintOptions();
opts.tiffColorDepth = ColorDepth.Format24bpp;
opts.imageType = ImageType.Tiff;
// Instantiate SheetRender object based on the first worksheet
const sheetRender = new SheetRender(worksheet, opts);
// Render the first page of the sheet to an image (returns binary data)
const imageData = sheetRender.toImage(0);
// Create a blob and provide a download link for the rendered TIFF image
const blob = new Blob([imageData], { type: 'image/tiff' });
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'outputSetPixelFormatRenderedImage.tiff';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download Rendered TIFF Image';
document.getElementById('result').innerHTML = '<p style="color: green;">Image rendered successfully! Click the download link to get the TIFF file.</p>';
});
</script>
</html>