com.github.naofum.epubconverter.ReadPdf.java Source code

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Here is the source code for com.github.naofum.epubconverter.ReadPdf.java

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/*
Copyright (C)2011 Ezio Querini
    
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.
    
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.
    
You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.github.naofum.epubconverter;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;

import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.SimpleBookmark;
import com.itextpdf.text.pdf.parser.ImageRenderInfo;
import com.itextpdf.text.pdf.parser.PdfImageObject;
import com.itextpdf.text.pdf.parser.PdfReaderContentParser;
import com.itextpdf.text.pdf.parser.PdfTextExtractor;
import com.itextpdf.text.pdf.parser.RenderListener;
import com.itextpdf.text.pdf.parser.TextRenderInfo;

public class ReadPdf {
    private static PdfReader reader;
    private static HashMap<String, String> info;
    static List<String> imageList;

    // Open pdf file
    public static boolean open(String filename) {
        try {
            reader = new PdfReader(filename);
            info = reader.getInfo();
        } catch (Exception e) {
            return true;
        } catch (OutOfMemoryError e) {
            return true;
        } catch (NoClassDefFoundError e) {
            return true;
        }
        return false;
    }

    // Number of pages
    public static int getPages() {
        return reader.getNumberOfPages();
    }

    // Title
    public static String getTitle() {
        String title = info.get("Title");
        if (title != null) {
            return title;
        }
        return "";
    }

    // Author
    public static String getAuthor() {
        String author = info.get("Author");
        if (author != null) {
            return author;
        }
        return "";
    }

    // Extract text
    public static String extractText(int page) {
        try {
            return PdfTextExtractor.getTextFromPage(reader, page) + "\n";
        } catch (Exception e) {
            System.err.println("Failed to extract text " + e.getMessage());
            return "";
        } catch (OutOfMemoryError e) {
            System.err.println("Out of memory in text extraction " + e.getMessage());
            return "";
        }
    }

    // Extract images
    public static List<String> getImages(int page) {
        imageList = new ArrayList<String>();
        PdfReaderContentParser parser = new PdfReaderContentParser(reader);
        renderListener listener = new renderListener();
        try {
            parser.processContent(page, listener);
        } catch (IOException e) {
            System.err.println("Failed to extract image " + e.getMessage());
        } catch (OutOfMemoryError e) {
            System.err.println("Out of memory in image extraction " + e.getMessage());
        }
        return imageList;
    }

    // Extract bookmarks
    public static String getBookmarks() {
        List<HashMap<String, Object>> list;
        try {
            list = SimpleBookmark.getBookmark(reader);
        } catch (ClassCastException e) {
            return "";
        }
        if (list == null) {
            return "";
        }

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        try {
            SimpleBookmark.exportToXML(list, baos, "UTF-8", false);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return baos.toString();
    }
}

// RenderListener helper class
class renderListener implements RenderListener {
    public void renderImage(ImageRenderInfo renderInfo) {
        try {
            // Get image
            PdfImageObject image = renderInfo.getImage();
            if (image != null) {
                ByteArrayOutputStream baos = new ByteArrayOutputStream();
                baos.write(image.getImageAsBytes());
                baos.flush();
                baos.close();

                // Check image type
                String imageType = image.getFileType();
                if (imageType == "png" || imageType == "gif" || imageType == "jpg") {
                    if (imageType == "jpg") {
                        imageType = "jpeg";
                    }

                    // Save to ePUB
                    String imageName = String.format("image%s.%s", renderInfo.getRef().getNumber(), imageType);
                    if (!WriteZip.addImage("OEBPS/" + imageName, baos.toByteArray())) {
                        ReadPdf.imageList.add(imageName);
                    }
                }

            }
        } catch (IOException e) {
            System.err.println("Failed to extract image (renderListener) " + e.getMessage());
        } catch (OutOfMemoryError e) {
            System.err.println("Out of memory in image extraction (renderListener) " + e.getMessage());
        }
    }

    // Nothing to do, just required methods
    public void renderText(TextRenderInfo renderInfo) {
    }

    public void beginTextBlock() {
    }

    public void endTextBlock() {
    }
}