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# Description of Changes Previously, highlight annotations in PDF documents converted to PDF/A format lost their opacity, resulting in highlights appearing completely opaque. This issue stemmed from LibreOffice’s PDF to PDF/A conversion process and affected both supported PDF/A variants (PDF/A-1B and PDF/A-2B). To resolve this, a new conversion method was implemented. Because PDF/A-1B does not support transparency, unlike PDF/A-2B, the input PDF must be preprocessed to flatten existing transparent objects when targeting PDF/A-1B. Changes: - Preprocess the PDF to handle highlight transparency when converting to PDF/A-1B; - LibreOffice's PDF to PDF/A conversion is now only used if fonts are not embedded or images require flattening; - If needed, missing fonts and flattened images are imported from the LibreOffice-converted file; - The document is traversed to remove elements non-compliant with PDF/A standards; - Updated metadata, including all metadata schemes, to ensure full compliance; - Added an ICC Profile if one was not already present. Any challenges encountered: - Since PDF/A-1B does not support transparency, the best workaround I found in other conversion tools was to draw close diagonal lines with the highlight color to simulate transparency, as seem in the example below. Closes #3106 Example from the issue: Original:  PDF/A-1B:  PDF/A-2B:  --- ## Checklist ### General - [x] I have read the [Contribution Guidelines](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/CONTRIBUTING.md) - [x] I have read the [Stirling-PDF Developer Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md) (if applicable) - [ ] I have read the [How to add new languages to Stirling-PDF](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md) (if applicable) - [x] I have performed a self-review of my own code - [x] My changes generate no new warnings ### Documentation - [ ] I have updated relevant docs on [Stirling-PDF's doc repo](https://github.com/Stirling-Tools/Stirling-Tools.github.io/blob/main/docs/) (if functionality has heavily changed) - [ ] I have read the section [Add New Translation Tags](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/HowToAddNewLanguage.md#add-new-translation-tags) (for new translation tags only) ### UI Changes (if applicable) - [ ] Screenshots or videos demonstrating the UI changes are attached (e.g., as comments or direct attachments in the PR) ### Testing (if applicable) - [x] I have tested my changes locally. Refer to the [Testing Guide](https://github.com/Stirling-Tools/Stirling-PDF/blob/main/DeveloperGuide.md#6-testing) for more details. I tested the changes using a variety of PDF files and verified PDF/A compliance of the outputs using VeraPDF. While these tests covered different scenarios and document types, PDF files can vary significantly in structure and complexity. As a result, the testing was not exhaustive, and while the results so far have been compliant, full compliance in all edge cases cannot be guaranteed. --------- Co-authored-by: Anthony Stirling <77850077+Frooodle@users.noreply.github.com>
This commit is contained in:
Tomás Bernardino
GitHub
parent
391bb4545b
commit
f82662aaaf
@ -1,16 +1,61 @@
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package stirling.software.SPDF.controller.api.converters;
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import java.awt.Color;
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import java.io.ByteArrayOutputStream;
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import io.github.pixee.security.Filenames;
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import io.swagger.v3.oas.annotations.Operation;
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import io.swagger.v3.oas.annotations.tags.Tag;
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import java.io.File;
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import java.io.IOException;
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import java.io.InputStream;
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import java.nio.file.Files;
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import java.nio.file.Path;
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import java.util.ArrayList;
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import java.util.Arrays;
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import java.util.Calendar;
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import java.util.Collections;
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import java.util.HashSet;
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import java.util.List;
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import java.util.Map;
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import java.util.Optional;
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import java.util.Set;
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import java.util.TimeZone;
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import lombok.extern.slf4j.Slf4j;
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import org.apache.commons.io.FileUtils;
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import org.apache.pdfbox.Loader;
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import org.apache.pdfbox.cos.COSArray;
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import org.apache.pdfbox.cos.COSBase;
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import org.apache.pdfbox.cos.COSDictionary;
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import org.apache.pdfbox.cos.COSName;
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import org.apache.pdfbox.pdfwriter.compress.CompressParameters;
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import org.apache.pdfbox.pdmodel.PDDocument;
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import org.apache.pdfbox.pdmodel.PDDocumentCatalog;
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import org.apache.pdfbox.pdmodel.PDDocumentInformation;
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import org.apache.pdfbox.pdmodel.PDPage;
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import org.apache.pdfbox.pdmodel.PDPageContentStream;
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import org.apache.pdfbox.pdmodel.PDResources;
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import org.apache.pdfbox.pdmodel.common.PDMetadata;
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import org.apache.pdfbox.pdmodel.common.PDStream;
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import org.apache.pdfbox.pdmodel.font.PDFont;
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import org.apache.pdfbox.pdmodel.font.PDFontDescriptor;
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import org.apache.pdfbox.pdmodel.font.PDTrueTypeFont;
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import org.apache.pdfbox.pdmodel.font.PDType0Font;
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import org.apache.pdfbox.pdmodel.graphics.PDXObject;
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import org.apache.pdfbox.pdmodel.graphics.color.PDOutputIntent;
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import org.apache.pdfbox.pdmodel.graphics.form.PDFormXObject;
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import org.apache.pdfbox.pdmodel.graphics.image.LosslessFactory;
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import org.apache.pdfbox.pdmodel.graphics.image.PDImageXObject;
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import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotation;
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import org.apache.pdfbox.pdmodel.interactive.annotation.PDAnnotationTextMarkup;
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import org.apache.pdfbox.pdmodel.interactive.viewerpreferences.PDViewerPreferences;
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import org.apache.xmpbox.XMPMetadata;
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import org.apache.xmpbox.schema.AdobePDFSchema;
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import org.apache.xmpbox.schema.DublinCoreSchema;
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import org.apache.xmpbox.schema.PDFAIdentificationSchema;
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import org.apache.xmpbox.schema.XMPBasicSchema;
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import org.apache.xmpbox.xml.DomXmpParser;
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import org.apache.xmpbox.xml.XmpSerializer;
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import org.springframework.http.MediaType;
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import org.springframework.http.ResponseEntity;
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import org.springframework.web.bind.annotation.ModelAttribute;
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@ -56,20 +101,121 @@ public class ConvertPDFToPDFA {
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: originalFileName;
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Path tempInputFile = null;
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Path tempOutputDir = null;
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byte[] fileBytes;
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Path loPdfPath = null; // Used for LibreOffice conversion output
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File preProcessedFile = null;
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int pdfaPart = 2;
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try {
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// Save uploaded file to temp location
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tempInputFile = Files.createTempFile("input_", ".pdf");
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inputFile.transferTo(tempInputFile);
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// Branch conversion based on desired output PDF/A format
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if ("pdfa".equals(outputFormat)) {
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preProcessedFile = tempInputFile.toFile();
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} else {
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pdfaPart = 1;
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preProcessedFile = preProcessHighlights(tempInputFile.toFile());
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}
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Set<String> missingFonts = new HashSet<>();
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boolean needImgs = false;
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try (PDDocument doc = Loader.loadPDF(preProcessedFile)) {
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missingFonts = findUnembeddedFontNames(doc);
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needImgs = (pdfaPart == 1) && hasTransparentImages(doc);
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if (!missingFonts.isEmpty() || needImgs) {
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// Run LibreOffice conversion to get flattened images and embedded fonts
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loPdfPath = runLibreOfficeConversion(preProcessedFile.toPath(), pdfaPart);
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}
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}
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fileBytes =
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convertToPdfA(
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preProcessedFile.toPath(), loPdfPath, pdfaPart, missingFonts, needImgs);
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String outputFilename = baseFileName + "_PDFA.pdf";
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return WebResponseUtils.bytesToWebResponse(
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fileBytes, outputFilename, MediaType.APPLICATION_PDF);
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} finally {
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// Clean up temporary files
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if (tempInputFile != null) {
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Files.deleteIfExists(tempInputFile);
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}
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if (loPdfPath != null && loPdfPath.getParent() != null) {
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FileUtils.deleteDirectory(loPdfPath.getParent().toFile());
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}
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if (preProcessedFile != null) {
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Files.deleteIfExists(preProcessedFile.toPath());
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}
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}
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}
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/**
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* Merge fonts & flattened images from loPdfPath into basePdfPath, then run the standard
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* PDFBox/A pipeline.
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*
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* @param basePdfPath Path to the original (or highlight‐preprocessed) PDF
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* @param loPdfPath Path to the LibreOffice–flattened PDF/A, or null if not used
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* @param pdfaPart 1 (PDF/A-1B) or 2 (PDF/A-2B)
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* @return the final PDF/A bytes
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*/
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private byte[] convertToPdfA(
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Path basePdfPath,
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Path loPdfPath,
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int pdfaPart,
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Set<String> missingFonts,
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boolean importImages)
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throws Exception {
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try (PDDocument baseDoc = Loader.loadPDF(basePdfPath.toFile())) {
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if (loPdfPath != null) {
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try (PDDocument loDoc = Loader.loadPDF(loPdfPath.toFile())) {
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if (!missingFonts.isEmpty()) {
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embedMissingFonts(loDoc, baseDoc, missingFonts);
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}
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if (importImages) {
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importFlattenedImages(loDoc, baseDoc);
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}
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}
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}
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return processWithPDFBox(baseDoc, pdfaPart);
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}
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}
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private byte[] processWithPDFBox(PDDocument document, int pdfaPart) throws Exception {
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removeElementsForPdfA(document, pdfaPart);
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mergeAndAddXmpMetadata(document, pdfaPart);
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addICCProfileIfNotPresent(document);
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// Mark the document as PDF/A
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PDDocumentCatalog catalog = document.getDocumentCatalog();
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catalog.setMetadata(
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document.getDocumentCatalog().getMetadata()); // Ensure metadata is linked
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catalog.setViewerPreferences(
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new PDViewerPreferences(catalog.getCOSObject())); // PDF/A best practice
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document.getDocument().setVersion(pdfaPart == 1 ? 1.4f : 1.7f);
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ByteArrayOutputStream baos = new ByteArrayOutputStream();
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if (pdfaPart == 1) {
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document.save(baos, CompressParameters.NO_COMPRESSION);
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} else {
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document.save(baos);
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}
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return baos.toByteArray();
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}
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private Path runLibreOfficeConversion(Path tempInputFile, int pdfaPart) throws Exception {
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// Create temp output directory
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tempOutputDir = Files.createTempDirectory("output_");
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Path tempOutputDir = Files.createTempDirectory("output_");
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// Determine PDF/A filter based on requested format
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String pdfFilter =
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"pdfa".equals(outputFormat)
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pdfaPart == 2
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? "pdf:writer_pdf_Export:{\"SelectPdfVersion\":{\"type\":\"long\",\"value\":\"2\"}}"
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: "pdf:writer_pdf_Export:{\"SelectPdfVersion\":{\"type\":\"long\",\"value\":\"1\"}}";
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@ -99,24 +245,454 @@ public class ConvertPDFToPDFA {
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File[] outputFiles = tempOutputDir.toFile().listFiles();
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if (outputFiles == null || outputFiles.length != 1) {
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throw new RuntimeException(
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"Expected exactly one output file but found "
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"Expected one output PDF, found "
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+ (outputFiles == null ? "none" : outputFiles.length));
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}
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fileBytes = FileUtils.readFileToByteArray(outputFiles[0]);
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String outputFilename = baseFileName + "_PDFA.pdf";
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return WebResponseUtils.bytesToWebResponse(
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fileBytes, outputFilename, MediaType.APPLICATION_PDF);
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} finally {
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// Clean up temporary files
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if (tempInputFile != null) {
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Files.deleteIfExists(tempInputFile);
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return outputFiles[0].toPath();
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}
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if (tempOutputDir != null) {
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FileUtils.deleteDirectory(tempOutputDir.toFile());
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private void embedMissingFonts(PDDocument loDoc, PDDocument baseDoc, Set<String> missingFonts)
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throws IOException {
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List<PDPage> loPages = new ArrayList<>();
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loDoc.getPages().forEach(loPages::add);
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List<PDPage> basePages = new ArrayList<>();
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baseDoc.getPages().forEach(basePages::add);
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for (int i = 0; i < loPages.size(); i++) {
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PDResources loRes = loPages.get(i).getResources();
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PDResources baseRes = basePages.get(i).getResources();
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for (COSName fontKey : loRes.getFontNames()) {
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PDFont loFont = loRes.getFont(fontKey);
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if (loFont == null) continue;
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String psName = loFont.getName();
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if (!missingFonts.contains(psName)) continue;
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PDFontDescriptor desc = loFont.getFontDescriptor();
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if (desc == null) continue;
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PDStream fontStream = null;
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if (desc.getFontFile() != null) {
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fontStream = desc.getFontFile();
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} else if (desc.getFontFile2() != null) {
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fontStream = desc.getFontFile2();
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} else if (desc.getFontFile3() != null) {
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fontStream = desc.getFontFile3();
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}
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if (fontStream == null) continue;
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try (InputStream in = fontStream.createInputStream()) {
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PDFont newFont = null;
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try {
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newFont = PDType0Font.load(baseDoc, in, false);
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} catch (IOException e1) {
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try {
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newFont = PDTrueTypeFont.load(baseDoc, in, null);
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} catch (IOException | IllegalArgumentException e2) {
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log.error("Could not embed font {}: {}", psName, e2.getMessage());
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continue;
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}
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}
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if (newFont != null) {
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baseRes.put(fontKey, newFont);
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}
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}
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}
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}
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}
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private Set<String> findUnembeddedFontNames(PDDocument doc) throws IOException {
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Set<String> missing = new HashSet<>();
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for (PDPage page : doc.getPages()) {
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PDResources res = page.getResources();
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for (COSName name : res.getFontNames()) {
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PDFont font = res.getFont(name);
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if (font != null && !font.isEmbedded()) {
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missing.add(font.getName());
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}
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}
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}
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return missing;
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}
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private void importFlattenedImages(PDDocument loDoc, PDDocument baseDoc) throws IOException {
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List<PDPage> loPages = new ArrayList<>();
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loDoc.getPages().forEach(loPages::add);
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List<PDPage> basePages = new ArrayList<>();
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baseDoc.getPages().forEach(basePages::add);
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for (int i = 0; i < loPages.size(); i++) {
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PDPage loPage = loPages.get(i);
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PDPage basePage = basePages.get(i);
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PDResources loRes = loPage.getResources();
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PDResources baseRes = basePage.getResources();
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Set<COSName> toReplace = detectTransparentXObjects(basePage);
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for (COSName name : toReplace) {
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PDXObject loXo = loRes.getXObject(name);
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if (!(loXo instanceof PDImageXObject img)) continue;
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PDImageXObject newImg = LosslessFactory.createFromImage(baseDoc, img.getImage());
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// replace the resource under the same name
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baseRes.put(name, newImg);
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}
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}
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}
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private Set<COSName> detectTransparentXObjects(PDPage page) {
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Set<COSName> transparentObjects = new HashSet<>();
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PDResources res = page.getResources();
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if (res == null) return transparentObjects;
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for (COSName name : res.getXObjectNames()) {
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try {
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PDXObject xo = res.getXObject(name);
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if (xo instanceof PDImageXObject img) {
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COSDictionary d = img.getCOSObject();
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if (d.containsKey(COSName.SMASK)
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|| isTransparencyGroup(d)
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|| d.getBoolean(COSName.INTERPOLATE, false)) {
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transparentObjects.add(name);
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}
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}
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} catch (IOException ioe) {
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log.error("Error processing XObject {}: {}", name.getName(), ioe.getMessage());
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}
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}
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return transparentObjects;
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}
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private boolean isTransparencyGroup(COSDictionary dict) {
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COSBase g = dict.getDictionaryObject(COSName.GROUP);
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return g instanceof COSDictionary gd
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&& COSName.TRANSPARENCY.equals(gd.getCOSName(COSName.S));
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}
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private boolean hasTransparentImages(PDDocument doc) {
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for (PDPage page : doc.getPages()) {
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PDResources res = page.getResources();
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if (res == null) continue;
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for (COSName name : res.getXObjectNames()) {
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try {
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PDXObject xo = res.getXObject(name);
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if (xo instanceof PDImageXObject img) {
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COSDictionary dict = img.getCOSObject();
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if (dict.containsKey(COSName.SMASK)) return true;
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COSBase g = dict.getDictionaryObject(COSName.GROUP);
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if (g instanceof COSDictionary gd
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&& COSName.TRANSPARENCY.equals(gd.getCOSName(COSName.S))) {
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return true;
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}
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if (dict.getBoolean(COSName.INTERPOLATE, false)) return true;
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}
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} catch (IOException ioe) {
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log.error("Error processing XObject {}: {}", name.getName(), ioe.getMessage());
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}
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}
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}
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return false;
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}
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private void sanitizePdfA(COSBase base, PDResources resources, int pdfaPart) {
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if (base instanceof COSDictionary dict) {
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if (pdfaPart == 1) {
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// Remove transparency-related elements
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COSBase group = dict.getDictionaryObject(COSName.GROUP);
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if (group instanceof COSDictionary gDict
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&& COSName.TRANSPARENCY.equals(gDict.getCOSName(COSName.S))) {
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dict.removeItem(COSName.GROUP);
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}
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dict.removeItem(COSName.SMASK);
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// Transparency blending constants (/CA, /ca) — disallowed in PDF/A-1
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dict.removeItem(COSName.CA);
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dict.removeItem(COSName.getPDFName("ca"));
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}
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// Interpolation (non-deterministic image scaling) — required to be false
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if (dict.containsKey(COSName.INTERPOLATE)
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&& dict.getBoolean(COSName.INTERPOLATE, true)) {
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dict.setBoolean(COSName.INTERPOLATE, false);
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}
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// Remove common forbidden features (for PDF/A 1 and 2)
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dict.removeItem(COSName.JAVA_SCRIPT);
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dict.removeItem(COSName.getPDFName("JS"));
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dict.removeItem(COSName.getPDFName("RichMedia"));
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dict.removeItem(COSName.getPDFName("Movie"));
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dict.removeItem(COSName.getPDFName("Sound"));
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dict.removeItem(COSName.getPDFName("Launch"));
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dict.removeItem(COSName.URI);
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dict.removeItem(COSName.getPDFName("GoToR"));
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dict.removeItem(COSName.EMBEDDED_FILES);
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dict.removeItem(COSName.FILESPEC);
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// Recurse through all entries in the dictionary
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for (Map.Entry<COSName, COSBase> entry : dict.entrySet()) {
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sanitizePdfA(entry.getValue(), resources, pdfaPart);
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}
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} else if (base instanceof COSArray arr) {
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// Recursively sanitize each item in the array
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for (COSBase item : arr) {
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sanitizePdfA(item, resources, pdfaPart);
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}
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||||
}
|
||||
}
|
||||
|
||||
private void removeElementsForPdfA(PDDocument doc, int pdfaPart) {
|
||||
|
||||
if (pdfaPart == 1) {
|
||||
// Remove Optional Content (Layers) - not allowed in PDF/A-1
|
||||
doc.getDocumentCatalog().getCOSObject().removeItem(COSName.getPDFName("OCProperties"));
|
||||
}
|
||||
|
||||
for (PDPage page : doc.getPages()) {
|
||||
if (pdfaPart == 1) {
|
||||
page.setAnnotations(Collections.emptyList());
|
||||
}
|
||||
PDResources res = page.getResources();
|
||||
// Clean page-level dictionary
|
||||
sanitizePdfA(page.getCOSObject(), res, pdfaPart);
|
||||
|
||||
// sanitize each Form XObject
|
||||
if (res != null) {
|
||||
for (COSName name : res.getXObjectNames()) {
|
||||
try {
|
||||
PDXObject xo = res.getXObject(name);
|
||||
if (xo instanceof PDFormXObject form) {
|
||||
sanitizePdfA(form.getCOSObject(), res, pdfaPart);
|
||||
} else if (xo instanceof PDImageXObject img) {
|
||||
sanitizePdfA(img.getCOSObject(), res, pdfaPart);
|
||||
}
|
||||
} catch (IOException ioe) {
|
||||
log.error("Cannot load XObject {}: {}", name.getName(), ioe.getMessage());
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
/** Embbeds the XMP metadata required for PDF/A compliance. */
|
||||
private void mergeAndAddXmpMetadata(PDDocument document, int pdfaPart) throws Exception {
|
||||
PDMetadata existingMetadata = document.getDocumentCatalog().getMetadata();
|
||||
XMPMetadata xmp;
|
||||
|
||||
// Load existing XMP if available
|
||||
if (existingMetadata != null) {
|
||||
try (InputStream xmpStream = existingMetadata.createInputStream()) {
|
||||
DomXmpParser parser = new DomXmpParser();
|
||||
parser.setStrictParsing(false);
|
||||
xmp = parser.parse(xmpStream);
|
||||
} catch (Exception e) {
|
||||
xmp = XMPMetadata.createXMPMetadata();
|
||||
}
|
||||
} else {
|
||||
xmp = XMPMetadata.createXMPMetadata();
|
||||
}
|
||||
|
||||
PDDocumentInformation docInfo = document.getDocumentInformation();
|
||||
if (docInfo == null) {
|
||||
docInfo = new PDDocumentInformation();
|
||||
}
|
||||
|
||||
String originalCreator = Optional.ofNullable(docInfo.getCreator()).orElse("Unknown");
|
||||
String originalProducer = Optional.ofNullable(docInfo.getProducer()).orElse("Unknown");
|
||||
|
||||
// Only keep the original creator so it can match xmp creator tool for compliance
|
||||
DublinCoreSchema dcSchema = xmp.getDublinCoreSchema();
|
||||
if (dcSchema != null) {
|
||||
List<String> existingCreators = dcSchema.getCreators();
|
||||
if (existingCreators != null) {
|
||||
for (String creator : new ArrayList<>(existingCreators)) {
|
||||
dcSchema.removeCreator(creator);
|
||||
}
|
||||
}
|
||||
} else {
|
||||
dcSchema = xmp.createAndAddDublinCoreSchema();
|
||||
}
|
||||
dcSchema.addCreator(originalCreator);
|
||||
|
||||
PDFAIdentificationSchema pdfaSchema =
|
||||
(PDFAIdentificationSchema) xmp.getSchema(PDFAIdentificationSchema.class);
|
||||
if (pdfaSchema == null) {
|
||||
pdfaSchema = xmp.createAndAddPDFAIdentificationSchema();
|
||||
}
|
||||
pdfaSchema.setPart(pdfaPart);
|
||||
pdfaSchema.setConformance("B");
|
||||
|
||||
XMPBasicSchema xmpBasicSchema = xmp.getXMPBasicSchema();
|
||||
if (xmpBasicSchema == null) {
|
||||
xmpBasicSchema = xmp.createAndAddXMPBasicSchema();
|
||||
}
|
||||
|
||||
AdobePDFSchema adobePdfSchema = xmp.getAdobePDFSchema();
|
||||
if (adobePdfSchema == null) {
|
||||
adobePdfSchema = xmp.createAndAddAdobePDFSchema();
|
||||
}
|
||||
|
||||
docInfo.setCreator(originalCreator);
|
||||
xmpBasicSchema.setCreatorTool(originalCreator);
|
||||
|
||||
docInfo.setProducer(originalProducer);
|
||||
adobePdfSchema.setProducer(originalProducer);
|
||||
|
||||
String originalAuthor = docInfo.getAuthor();
|
||||
if (originalAuthor != null && !originalAuthor.isBlank()) {
|
||||
docInfo.setAuthor(null);
|
||||
// If the author is set, we keep it in the XMP metadata
|
||||
if (!originalCreator.equals(originalAuthor)) {
|
||||
dcSchema.addCreator(originalAuthor);
|
||||
}
|
||||
}
|
||||
|
||||
String title = docInfo.getTitle();
|
||||
if (title != null && !title.isBlank()) {
|
||||
dcSchema.setTitle(title);
|
||||
}
|
||||
String subject = docInfo.getSubject();
|
||||
if (subject != null && !subject.isBlank()) {
|
||||
dcSchema.addSubject(subject);
|
||||
}
|
||||
String keywords = docInfo.getKeywords();
|
||||
if (keywords != null && !keywords.isBlank()) {
|
||||
adobePdfSchema.setKeywords(keywords);
|
||||
}
|
||||
|
||||
// Set creation and modification dates
|
||||
Calendar now = Calendar.getInstance(TimeZone.getTimeZone("UTC"));
|
||||
Calendar originalCreationDate = docInfo.getCreationDate();
|
||||
if (originalCreationDate == null) {
|
||||
originalCreationDate = now;
|
||||
}
|
||||
docInfo.setCreationDate(originalCreationDate);
|
||||
xmpBasicSchema.setCreateDate(originalCreationDate);
|
||||
|
||||
docInfo.setModificationDate(now);
|
||||
xmpBasicSchema.setModifyDate(now);
|
||||
xmpBasicSchema.setMetadataDate(now);
|
||||
|
||||
// Serialize the created metadata so it can be attached to the existent metadata
|
||||
ByteArrayOutputStream xmpOut = new ByteArrayOutputStream();
|
||||
new XmpSerializer().serialize(xmp, xmpOut, true);
|
||||
|
||||
PDMetadata newMetadata = new PDMetadata(document);
|
||||
newMetadata.importXMPMetadata(xmpOut.toByteArray());
|
||||
document.getDocumentCatalog().setMetadata(newMetadata);
|
||||
}
|
||||
|
||||
private void addICCProfileIfNotPresent(PDDocument document) throws Exception {
|
||||
if (document.getDocumentCatalog().getOutputIntents().isEmpty()) {
|
||||
try (InputStream colorProfile = getClass().getResourceAsStream("/icc/sRGB2014.icc")) {
|
||||
PDOutputIntent outputIntent = new PDOutputIntent(document, colorProfile);
|
||||
outputIntent.setInfo("sRGB IEC61966-2.1");
|
||||
outputIntent.setOutputCondition("sRGB IEC61966-2.1");
|
||||
outputIntent.setOutputConditionIdentifier("sRGB IEC61966-2.1");
|
||||
outputIntent.setRegistryName("http://www.color.org");
|
||||
document.getDocumentCatalog().addOutputIntent(outputIntent);
|
||||
} catch (Exception e) {
|
||||
log.error("Failed to load ICC profile: {}", e.getMessage());
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
private File preProcessHighlights(File inputPdf) throws Exception {
|
||||
|
||||
try (PDDocument document = Loader.loadPDF(inputPdf)) {
|
||||
|
||||
for (PDPage page : document.getPages()) {
|
||||
// Retrieve the annotations on the page.
|
||||
List<PDAnnotation> annotations = page.getAnnotations();
|
||||
for (PDAnnotation annot : annotations) {
|
||||
// Process only highlight annotations.
|
||||
if ("Highlight".equals(annot.getSubtype())
|
||||
&& annot instanceof PDAnnotationTextMarkup highlight) {
|
||||
// Create a new appearance stream with the same bounding box.
|
||||
float[] colorComponents =
|
||||
highlight.getColor() != null
|
||||
? highlight.getColor().getComponents()
|
||||
: new float[] {1f, 1f, 0f};
|
||||
Color highlightColor =
|
||||
new Color(
|
||||
colorComponents[0], colorComponents[1], colorComponents[2]);
|
||||
|
||||
float[] quadPoints = highlight.getQuadPoints();
|
||||
if (quadPoints != null) {
|
||||
try (PDPageContentStream cs =
|
||||
new PDPageContentStream(
|
||||
document,
|
||||
page,
|
||||
PDPageContentStream.AppendMode.PREPEND,
|
||||
true,
|
||||
true)) {
|
||||
|
||||
cs.setStrokingColor(highlightColor);
|
||||
cs.setLineWidth(0.05f);
|
||||
float spacing = 2f;
|
||||
// Draw diagonal lines across the highlight area to simulate
|
||||
// transparency.
|
||||
for (int i = 0; i < quadPoints.length; i += 8) {
|
||||
float minX =
|
||||
Math.min(
|
||||
Math.min(quadPoints[i], quadPoints[i + 2]),
|
||||
Math.min(quadPoints[i + 4], quadPoints[i + 6]));
|
||||
float maxX =
|
||||
Math.max(
|
||||
Math.max(quadPoints[i], quadPoints[i + 2]),
|
||||
Math.max(quadPoints[i + 4], quadPoints[i + 6]));
|
||||
float minY =
|
||||
Math.min(
|
||||
Math.min(quadPoints[i + 1], quadPoints[i + 3]),
|
||||
Math.min(quadPoints[i + 5], quadPoints[i + 7]));
|
||||
float maxY =
|
||||
Math.max(
|
||||
Math.max(quadPoints[i + 1], quadPoints[i + 3]),
|
||||
Math.max(quadPoints[i + 5], quadPoints[i + 7]));
|
||||
|
||||
float width = maxX - minX;
|
||||
float height = maxY - minY;
|
||||
|
||||
for (float y = minY; y <= maxY; y += spacing) {
|
||||
float len = Math.min(width, maxY - y);
|
||||
cs.moveTo(minX, y);
|
||||
cs.lineTo(minX + len, y + len);
|
||||
}
|
||||
for (float x = minX + spacing; x <= maxX; x += spacing) {
|
||||
float len = Math.min(maxX - x, height);
|
||||
cs.moveTo(x, minY);
|
||||
cs.lineTo(x + len, minY + len);
|
||||
}
|
||||
}
|
||||
|
||||
cs.stroke();
|
||||
}
|
||||
}
|
||||
|
||||
page.getAnnotations().remove(highlight);
|
||||
COSDictionary pageDict = page.getCOSObject();
|
||||
|
||||
if (pageDict.containsKey(COSName.GROUP)) {
|
||||
COSDictionary groupDict =
|
||||
(COSDictionary) pageDict.getDictionaryObject(COSName.GROUP);
|
||||
|
||||
if (groupDict != null) {
|
||||
if (COSName.TRANSPARENCY
|
||||
.getName()
|
||||
.equalsIgnoreCase(groupDict.getNameAsString(COSName.S))) {
|
||||
pageDict.removeItem(COSName.GROUP);
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
}
|
||||
// Save the modified document to a temporary file.
|
||||
File preProcessedFile = Files.createTempFile("preprocessed_", ".pdf").toFile();
|
||||
document.save(preProcessedFile);
|
||||
return preProcessedFile;
|
||||
}
|
||||
}
|
||||
}
|
||||
|
||||
BIN
stirling-pdf/src/main/resources/icc/sRGB2014.icc
Normal file
BIN
stirling-pdf/src/main/resources/icc/sRGB2014.icc
Normal file
Binary file not shown.
Loading…
x
Reference in New Issue
Block a user