io.github.astrapisixtynine.pdf.to.text.pdfbox.PdfToTextExtensions Maven / Gradle / Ivy
/**
* The MIT License
*
* Copyright (C) 2022 Asterios Raptis
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
* LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
* OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
* WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/
package io.github.astrapisixtynine.pdf.to.text.pdfbox;
import java.awt.image.BufferedImage;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Level;
import javax.imageio.ImageIO;
import org.apache.pdfbox.Loader;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.rendering.ImageType;
import org.apache.pdfbox.rendering.PDFRenderer;
import org.apache.pdfbox.text.PDFTextStripper;
import io.github.astrapi69.file.create.FileFactory;
import io.github.astrapi69.file.modify.ModifyFileExtensions;
import io.github.astrapi69.io.file.FileExtension;
import io.github.astrapi69.io.file.FilenameExtensions;
import io.github.astrapi69.io.shell.LinuxShellExecutor;
import io.github.astrapisixtynine.pdf.to.text.info.ConversionResult;
import lombok.extern.java.Log;
/**
* The class {@link PdfToTextExtensions} provides functionality to convert a PDF file into a text
* file using either direct text extraction or Optical Character Recognition (OCR)
*/
@Log
public final class PdfToTextExtensions
{
/**
* Private constructor to prevent instantiation
*/
private PdfToTextExtensions()
{
}
/**
* Converts a text PDF file to a text file extracting text from all pages
*
* @param pdfFile
* the input PDF file
* @param resultDir
* the directory where the output text file will be stored
* @return the generated text file
* @throws IOException
* if an I/O error occurs
*/
public static File pdfToText(File pdfFile, File resultDir) throws IOException
{
int numberOfPages;
try (PDDocument document = Loader.loadPDF(pdfFile))
{
numberOfPages = document.getNumberOfPages();
}
return pdfToText(pdfFile, resultDir, 0, numberOfPages);
}
/**
* Converts a text PDF file to a text file, with the option to specify a range of pages to
* extract
*
* @param pdfFile
* the input PDF file
* @param resultDir
* the directory where the output text file will be stored
* @param startPageValue
* the starting page number
* @param endPageValue
* the ending page number
* @return the generated text file
* @throws IOException
* if an I/O error occurs
*/
public static File pdfToText(File pdfFile, File resultDir, int startPageValue, int endPageValue)
throws IOException
{
String txtFileName;
String fileName;
fileName = FilenameExtensions.getFilenameWithoutExtension(pdfFile);
txtFileName = fileName + FileExtension.TXT.getExtension();
File resultTextFile = FileFactory.newFile(resultDir, txtFileName);
try (PDDocument document = Loader.loadPDF(pdfFile);
BufferedWriter wr = new BufferedWriter(
new OutputStreamWriter(new FileOutputStream(resultTextFile))))
{
PDFTextStripper stripper = new PDFTextStripper();
stripper.setStartPage(startPageValue); // Start extracting from first page
stripper.setEndPage(endPageValue); // Extract till the end
stripper.writeText(document, wr);
}
return resultTextFile;
}
/**
* Converts a text or image PDF file to text using image processing and OCR
*
* @param pdfFile
* the input PDF file
* @param outputDir
* the directory where the output files will be stored
* @return the result of the conversion containing image files, text files, and the final result
* text file
* @throws IOException
* if an I/O error occurs
* @throws InterruptedException
* if the process is interrupted
*/
public static ConversionResult convertPdfToTextfile(File pdfFile, File outputDir)
throws IOException, InterruptedException
{
return convertPdfToTextfile(pdfFile, outputDir, "deu");
}
/**
* Converts a text or image PDF file to text using image processing and OCR
*
* @param pdfFile
* the input PDF file
* @param outputDir
* the directory where the output files will be stored
* @param ocrLanguage
* the ocr language
* @return the {@link ConversionResult} object of the OCR conversion process containing image
* files, text files, and the final result text file
* @throws IOException
* if an I/O error occurs
* @throws InterruptedException
* if the process is interrupted
*/
public static ConversionResult convertPdfToTextfile(File pdfFile, File outputDir,
String ocrLanguage) throws IOException, InterruptedException
{
String txtFileName;
String fileName;
fileName = FilenameExtensions.getFilenameWithoutExtension(pdfFile);
txtFileName = fileName + FileExtension.TXT.getExtension();
File resultTextFile = FileFactory.newFile(outputDir, txtFileName);
// step 1: convert the pdf file to image files
List imageFiles = getImageFiles(pdfFile, outputDir);
// step 2: convert the image files to text files
String shellPath = "/bin/sh";
List textFiles = getTextFiles(imageFiles, outputDir, shellPath, ocrLanguage);
// step 3: concatenate all text files to one
ModifyFileExtensions.concatenateAll(textFiles, resultTextFile);
return ConversionResult.builder().imageFiles(imageFiles).textFiles(textFiles)
.resultTextFile(resultTextFile).build();
}
/**
* Converts text or image PDF files into text files using Tesseract OCR
*
* @param imageFiles
* the list of image files to be processed
* @param resultDir
* the directory where the text files will be stored
* @param shellPath
* the shell path for executing commands
* @return the list of generated text files
* @throws IOException
* if an I/O error occurs
* @throws InterruptedException
* if the process is interrupted
*/
public static List getTextFiles(List imageFiles, File resultDir, String shellPath)
throws IOException, InterruptedException
{
return getTextFiles(imageFiles, resultDir, shellPath, "deu");
}
/**
* Converts text or image PDF files into text files using Tesseract OCR
*
* @param imageFiles
* the list of image files to be processed
* @param resultDir
* the directory where the text files will be stored
* @param shellPath
* the shell path for executing commands
* @param ocrLanguage
* the ocr language
* @return the list of generated text files
* @throws IOException
* if an I/O error occurs
* @throws InterruptedException
* if the process is interrupted
*/
public static List getTextFiles(List imageFiles, File resultDir, String shellPath,
String ocrLanguage) throws IOException, InterruptedException
{
String output;
String command;
String commandPrefix;
commandPrefix = "tesseract";
String executionPath = resultDir.toString();
List textFiles = new ArrayList<>();
for (int page = 0; page < imageFiles.size(); ++page)
{
File imageFile = imageFiles.get(page);
String imageFileName = imageFile.getName();
String textFileName = FilenameExtensions.getFilenameWithoutExtension(imageFile);
command = commandPrefix + " " + imageFileName + " " + textFileName + " -l "
+ ocrLanguage;
log.log(Level.INFO, "Executing command: " + command);
output = LinuxShellExecutor.execute(shellPath, executionPath, command);
log.log(Level.INFO, "Output from command: " + output);
File textFile = new File(resultDir, textFileName + ".txt");
FileFactory.newFile(textFile);
textFiles.add(textFile);
}
return textFiles;
}
/**
* Converts a text or image PDF file into image files for each page
*
* @param pdfFile
* the input PDF file
* @param outputDir
* the directory where the image files will be stored
* @return the list of generated image files
* @throws IOException
* if an I/O error occurs
*/
public static List getImageFiles(File pdfFile, File outputDir) throws IOException
{
return getImageFiles(pdfFile, outputDir, "png");
}
/**
* Converts a text or image PDF file into image files for each page
*
* @param pdfFile
* the input PDF file
* @param outputDir
* the directory where the image files will be stored
* @param imageFileFormatName
* the image file format containing the informal name of the image file format
* @return the list of generated image files
* @throws IOException
* if an I/O error occurs
*/
public static List getImageFiles(File pdfFile, File outputDir, String imageFileFormatName)
throws IOException
{
List imageFiles = new ArrayList<>();
String fileName = FilenameExtensions.getFilenameWithoutExtension(pdfFile);
try (PDDocument document = Loader.loadPDF(pdfFile))
{
PDFRenderer pdfRenderer = new PDFRenderer(document);
for (int page = 0; page < document.getNumberOfPages(); ++page)
{
BufferedImage image = pdfRenderer.renderImageWithDPI(page, 300, ImageType.RGB);
File imageFile = new File(outputDir, fileName + "page_" + (page + 1) + ".png");
FileFactory.newFile(imageFile);
ImageIO.write(image, imageFileFormatName, imageFile);
imageFiles.add(imageFile);
}
}
return imageFiles;
}
}
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