pdfbox - PDFBox：删除图像后面的文本

Question

我需要将 pdf 分成两份，一份是图片，一份是文本。我不想删除图像后面的文本，它应该是图像 pdf 的一部分。我只想提取 PDF 中的顶层文本。有人可以帮忙吗？

我已经通过循环 pdf 运算符将图像和文本提取到两个 pdf 中。当不删除 PDF 后面的文本时，我遇到了麻烦。

标签： pdfbox

Answer 1

删除文本的代码：

PDDocument document = null;
    try {
        document = PDDocument.load(new File(inputfilePath), password);
        PDPageTree allPages = document.getDocumentCatalog().getPages();
        for (int i = 0; i < allPages.getCount(); i++) {
            PDPage page = (PDPage) allPages.get(i);
            PDFStreamParser parser = new PDFStreamParser(page);

            parser.parse();
            List tokens = parser.getTokens();
            List newTokens = new ArrayList();
            for (int j = 0; j < tokens.size(); j++) {
                Object token = tokens.get(j);
                if (token instanceof Operator) {
                    Operator op = (Operator) token;

                    if (op.getName().equalsIgnoreCase(
                            "tj")) {
                        try {
                            // remove the one argument to this operator
                            newTokens.remove(newTokens.size() - 1);
                        } catch (Exception e) {
                            e.printStackTrace();
                        }
                        continue;
                    }
                    // Header doesn't contain versioninfo

                }
                newTokens.add(token);

            }
            PDStream newContents = new PDStream(document);
            ContentStreamWriter writer = new ContentStreamWriter(newContents.createOutputStream());
            writer.writeTokens(newTokens);
            // In writeTokens method, I closed the output stream.. This is
            // for future reference.. or it will throw stream not closed
            // error
            newContents.addCompression();
            page.setContents(newContents);
            if (DEBUG)
                System.out.println("Background image pdf creation process");
            document.setAllSecurityToBeRemoved(true);
            document.save(outputFolder + "/img_" + fileName);

为了删除图像和阴影，我使用了以下代码：

for (int j = 0; j < tokens.size(); j++) {
                Object token = tokens.get(j);
                if (token instanceof Operator) {
                    Operator op = (Operator) token;

                    // Text Extraction removing image and shades
                    if (op.getName().equalsIgnoreCase("do") || op.getName().equalsIgnoreCase("sh")

                            || op.getName().equalsIgnoreCase("gs") || op.getName().equalsIgnoreCase("bi")
                            || op.getName().equalsIgnoreCase("id") || op.getName().equalsIgnoreCase("ei")
                            || op.getName().equalsIgnoreCase("bmc") || op.getName().equalsIgnoreCase("bdc")
                            || op.getName().equalsIgnoreCase("emc") || op.getName().equalsIgnoreCase("m")
                            || op.getName().equalsIgnoreCase("w")
                            || op.getName().equalsIgnoreCase("re")

                    ) {
                        // remove the one argument to this operator
                        newTokens.remove(newTokens.size() - 1);
                        continue;
                    }
                }
                newTokens.add(token);

            }