用 JavaScript 通过 C++ 创建透明 Excel 工作表图片
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有时，您需要将工作表的图像生成为透明图像。您希望将透明度应用于所有没有填充颜色的单元格。Aspose.Cells提供ImageOrPrintOptions.transparent属性以将透明度应用于工作表图像。当此属性为false时，没有填充颜色的单元格将以白色绘制，当为true时，没有填充颜色的单元格将以透明绘制。
在下面的工作表图片中，没有应用透明度。没有填充颜色的单元格绘制成了白色。
| 没有透明度的输出：单元格背景为白色 |
|---|
 |
而在下面的工作表图片中，应用了透明度。没有填充颜色的单元格是透明的。
| 启用透明度输出 |
|---|
 |
下面的示例代码从 Excel 工作表生成一个透明的图像。
<!DOCTYPE html>
<html>
<head>
<title>Aspose.Cells Create Transparent Image Example</title>
</head>
<body>
<h1>Create Transparent Image Example</h1>
<input type="file" id="fileInput" accept=".xls,.xlsx,.xlsm,.csv" />
<button id="runExample">Create Transparent PNG</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 } = 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();
// Create workbook object from uploaded file
const wb = new Workbook(new Uint8Array(arrayBuffer));
// Access first worksheet
const sheet = wb.worksheets.get(0);
// Apply different image or print options
const imgOption = new ImageOrPrintOptions();
imgOption.imageType = ImageType.Png;
imgOption.horizontalResolution = 200;
imgOption.verticalResolution = 200;
imgOption.onePagePerSheet = true;
// Apply transparency to the output image
imgOption.transparent = true;
// Create image after applying image or print options
const sr = new SheetRender(sheet, imgOption);
const outputData = await sr.toImage(0);
const blob = new Blob([outputData], { type: 'image/png' });
const downloadLink = document.getElementById('downloadLink');
downloadLink.href = URL.createObjectURL(blob);
downloadLink.download = 'outputCreateTransparentImage.png';
downloadLink.style.display = 'block';
downloadLink.textContent = 'Download PNG Image';
document.getElementById('result').innerHTML = '<p style="color: green;">Image created successfully! Click the download link to get the PNG file.</p>';
});
</script>
</html>