Add hidden text encoding latex within pdf document

moritzfl · Mar 3, 2019 · f877279 · f877279
1 parent b72db4c
commit f877279
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Showing 3 changed files with 30 additions and 4 deletions.
diff --git a/pom.xml b/pom.xml
@@ -4,7 +4,7 @@
     <modelVersion>4.0.0</modelVersion>
     <groupId>com.github.moritzfl</groupId>
     <artifactId>mathematicallatexhelper</artifactId>
-    <version>2.2.0.0</version>
+    <version>2.2.1.0</version>
     <name>mathematicallatexhelper</name>
     <prerequisites>
         <maven>3</maven>

diff --git a/src/main/java/de/moritzf/latexhelper/Export.java b/src/main/java/de/moritzf/latexhelper/Export.java
@@ -15,6 +15,7 @@
 
 
 import java.awt.*;
+import java.awt.Image;
 import java.awt.datatransfer.DataFlavor;
 import java.awt.datatransfer.Transferable;
 import java.awt.datatransfer.UnsupportedFlavorException;
@@ -32,14 +33,17 @@
 import javax.swing.filechooser.FileSystemView;
 
 
-import com.itextpdf.text.Document;
-import com.itextpdf.text.DocumentException;
+import com.itextpdf.text.*;
 
 import de.moritzf.latexhelper.util.SteganographyUtil;
+import gutenberg.itext.Emitter;
 import gutenberg.itext.ITextContext;
 import gutenberg.itext.PygmentsAdapter;
 import gutenberg.itext.Styles;
+import gutenberg.itext.emitter.RichTextEmitter;
 import gutenberg.itext.emitter.SourceCodeLaTeXExtension;
+import gutenberg.itext.model.Markdown;
+import gutenberg.itext.model.RichText;
 import gutenberg.itext.model.SourceCode;
 import gutenberg.pygments.Pygments;
 import gutenberg.pygments.styles.DefaultStyle;
@@ -161,8 +165,17 @@ private static void generatePdf(String expression, File file) throws IOException
             SourceCodeLaTeXExtension extension = new SourceCodeLaTeXExtension(pygmentsAdapter);
             SourceCode sourceCode = new SourceCode("latex", expression);
 
+            com.itextpdf.text.Font font = new com.itextpdf.text.Font();
+            font.setColor(BaseColor.WHITE);
+            font.setSize(0.001f);
+            Chunk chunk = new Chunk("\\##latex##\\" + expression + "\\##latex##\\");
+            chunk.setFont(font);
+
+            document.add(chunk);
+
             extension.emit(sourceCode, iTextContext);
-            iTextContext.getDocument().addHeader("latex", expression);
+            document.addHeader("latex", expression);
+
             iTextContext.close();
         } catch (DocumentException e) {
 

diff --git a/src/main/java/de/moritzf/latexhelper/LatexImportingTextArea.java b/src/main/java/de/moritzf/latexhelper/LatexImportingTextArea.java
@@ -2,6 +2,7 @@
 
 
 import com.itextpdf.text.pdf.PdfReader;
+import com.itextpdf.text.pdf.parser.PdfTextExtractor;
 import de.moritzf.latexhelper.util.ImageFileUtil;
 import de.moritzf.latexhelper.util.SteganographyUtil;
 import mathpix.MathPix;
@@ -30,6 +31,8 @@
 import java.util.List;
 import java.util.logging.Level;
 import java.util.logging.Logger;
+import java.util.regex.Matcher;
+import java.util.regex.Pattern;
 
 /**
  * Text area that can work with images that have content hidden by steganography. If such content is detected, it
@@ -124,6 +127,16 @@ private String extractFromPdf(File pdfFile) {
         try {
             reader = new PdfReader(pdfFile.getAbsolutePath());
             latex = reader.getInfo().get("latex");
+            if (latex == null || latex.isEmpty()) {
+                String text = PdfTextExtractor.getTextFromPage(reader, 1);
+                LOGGER.log(Level.INFO, text);
+                Pattern pattern = Pattern.compile("\\\\##latex##\\\\(?<latex>.*)\\\\##latex##\\\\");
+                Matcher matcher = pattern.matcher(text);
+                if (matcher.find()) {
+                    latex = matcher.group("latex");
+                }
+
+            }
         } catch (Exception e) {
             LOGGER.log(Level.SEVERE, "Could not read pdf. Perhaps the file used was not a valid pdf file.");
         }