使用apache PDF-Box插入PDF附件的缩略图

Question

我有一个代码将文件附加到PDF文件。

PDDocument doc = new PDDocument();
PDPage page = new PDPage();
doc.addPage(page);

// read attachment file
File file = new File("/Users/TMac/Projects/Web/dir/index.html");
FileInputStream inputStream = new FileInputStream(file);

PDEmbeddedFile pdEmbeddedFile = new PDEmbeddedFile(doc, inputStream );
pdEmbeddedFile.setSubtype( "application/octet-stream" );

PDComplexFileSpecification fs = new PDComplexFileSpecification();
fs.setEmbeddedFile( pdEmbeddedFile );
fs.setFile("index.html");

int offsetX = 20;
int offsetY = 600;

PDAnnotationFileAttachment txtLink = new PDAnnotationFileAttachment();
txtLink.setFile(fs);

// Set the rectangle containing the link
PDRectangle position = new PDRectangle();
position.setLowerLeftX(offsetX);
position.setLowerLeftY(offsetY);
position.setUpperRightX(offsetX + 20);
position.setUpperRightY(offsetY + 20);
txtLink.setRectangle(position);

page.getAnnotations().add(txtLink);

doc.save("/Users/TMac/Projects/PDF/outputFiles/testHTML.pdf");
doc.close();

问题是附件图标如下所示：

我需要用自定义图像替换此图标。我找到了一些与文本链接相关的示例。当我点击该图像时，它应该打开文件。附件代码（上面的代码）工作正常。如何将自定义图像添加为缩略图？

Answer 1

您需要创建一个外观流：

PDAnnotationFileAttachment txtLink = new PDAnnotationFileAttachment();
txtLink.setFile(fs);
// Set the rectangle containing the link
int offsetX = 20;
int offsetY = 600;
PDRectangle position = new PDRectangle();
position.setLowerLeftX(offsetX);
position.setLowerLeftY(offsetY);
position.setUpperRightX(offsetX + 20);
position.setUpperRightY(offsetY + 20);
txtLink.setRectangle(position);

PDAppearanceDictionary appearanceDictionary = new PDAppearanceDictionary();
PDAppearanceStream appearanceStream = new PDAppearanceStream(doc);
appearanceStream.setResources(new PDResources());
PDRectangle bbox = new PDRectangle(txtLink.getRectangle().getWidth(), txtLink.getRectangle().getHeight());
appearanceStream.setBBox(bbox);
try (PDPageContentStream cs = new PDPageContentStream(doc, appearanceStream))
{
    PDImageXObject image = PDImageXObject.createFromFile("image.jpg", doc);
    cs.drawImage(image, 0, 0);
}
appearanceDictionary.setNormalAppearance(appearanceStream);
txtLink.setAppearance(appearanceDictionary);

page.getAnnotations().add(txtLink);