compresser un PDF avec de grandes images via java

Vous cherchez un moyen de compresser des images dans un pdf et de sortir un PDF pour l'archivage. Je ne peux pas compresser les images avant la création car cela compromettrait la qualité de l'impression.

La taille de chaque pdf est d'environ 8 Mo, la majeure partie étant composée de 2 images. Les images sont au format png et sont introduites en pdf lors de la génération (générateur tiers utilisé)

Existe-t-il un moyen de les compresser en java sans utiliser un outil tiers. J'ai essayé avec pdfbox itext et un 3ème partie exe(neevia), la 3ème partie de l'outil le seul qui m'a donné aucun résultat jusqu'à présent(jusqu'à environ un demi-MO), mais je ne veux pas abandonner le contrôle d'un fichier exe. Exemple de code est ci-dessous.

import java.io.BufferedReader;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.Arrays;

import org.apache.pdfbox.exceptions.COSVisitorException;
import org.apache.pdfbox.pdmodel.PDDocument;
import org.apache.pdfbox.pdmodel.common.PDStream;

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfStamper;
import com.itextpdf.text.pdf.PdfWriter;

public class compressPDF {

public static void main (String[] args) throws IOException, DocumentException, COSVisitorException {


    /*
     * Using PDF Box
     */

    PDDocument doc; // = new PDDocument();

    doc = PDDocument.load("C:/_dev_env_/TEMP/compressPDF/TRPT_135002_1470_20131212_121423.PDF");

    PDStream stream= new PDStream(doc);
    stream.addCompression();

    doc.save("C:/_dev_env_/TEMP/compressPDF/compressed_pdfBox.pdf");

    doc.close();

    /*
     * Using itext
     */

    PdfReader reader = new PdfReader("C:/_dev_env_/TEMP/compressPDF/TRPT_135002_1470_20131212_121423.PDF");

    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream("C:/_dev_env_/TEMP/compressPDF/compressed_Itext.pdf"), PdfWriter.VERSION_1_5);
    stamper.setFullCompression();
    stamper.getWriter().setCompressionLevel(50);
    int total = reader.getNumberOfPages() + 1;
    for (int i = 1; i < total; i++) {
        reader.setPageContent(i, reader.getPageContent(i));
    }
    stamper.close();
    reader.close();

    /*
     * Using 3rd party - Neevia 
     */
    try {
    Process process = new ProcessBuilder("C:/Program Files (x86)/neeviaPDF.com/PDFcompress/cmdLine/CLcompr.exe","C:/_dev_env_/TEMP/compressPDF/TRPT_135002_1470_20131212_121423.PDF", "C:/_dev_env_/TEMP/compressPDF/compressed_Neevia.pdf").start();
    InputStream is = process.getInputStream();
    InputStreamReader isr = new InputStreamReader(is);
    BufferedReader br = new BufferedReader(isr);
    String line;

    System.out.printf("Output of running %s is:", Arrays.toString(args));

    while ((line = br.readLine()) != null) {
      System.out.println(line);
    }
    } catch (Exception e) {
        System.out.println(e);
    } finally {
        System.out.println("Created!!");
    }

}

}
Author: Daniel Mulcahy, 2013-12-16
Source

1 answers

J'ai utilisé le code ci-dessous pour une preuve de concept... Fonctionne un régal:) Merci à Bruno de m'avoir mis sur le bon chemin:) 

package compressPDF;

import java.awt.Graphics2D;
import java.awt.geom.AffineTransform;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.FileOutputStream;
import java.io.IOException;

import javax.imageio.ImageIO;

import com.itextpdf.text.DocumentException;
import com.itextpdf.text.pdf.PRStream;
import com.itextpdf.text.pdf.PdfName;
import com.itextpdf.text.pdf.PdfNumber;
import com.itextpdf.text.pdf.PdfObject;
import com.itextpdf.text.pdf.PdfReader;
import com.itextpdf.text.pdf.PdfStamper;
import com.itextpdf.text.pdf.parser.PdfImageObject;

public class ResizeImage {

/** The resulting PDF file. */
//public static String RESULT = "results/part4/chapter16/resized_image.pdf";
/** The multiplication factor for the image. */
public static float FACTOR = 0.5f;

/**
 * Manipulates a PDF file src with the file dest as result
 * @param src the original PDF
 * @param dest the resulting PDF
 * @throws IOException
 * @throws DocumentException 
 */
public void manipulatePdf(String src, String dest) throws IOException, DocumentException {
    PdfName key = new PdfName("ITXT_SpecialId");
    PdfName value = new PdfName("123456789");
    // Read the file
    PdfReader reader = new PdfReader(src);
    int n = reader.getXrefSize();
    PdfObject object;
    PRStream stream;
    // Look for image and manipulate image stream
    for (int i = 0; i < n; i++) {
        object = reader.getPdfObject(i);
        if (object == null || !object.isStream())
            continue;
        stream = (PRStream)object;
       // if (value.equals(stream.get(key))) {
        PdfObject pdfsubtype = stream.get(PdfName.SUBTYPE);
        System.out.println(stream.type());
        if (pdfsubtype != null && pdfsubtype.toString().equals(PdfName.IMAGE.toString())) {
            PdfImageObject image = new PdfImageObject(stream);
            BufferedImage bi = image.getBufferedImage();
            if (bi == null) continue;
            int width = (int)(bi.getWidth() * FACTOR);
            int height = (int)(bi.getHeight() * FACTOR);
            BufferedImage img = new BufferedImage(width, height, BufferedImage.TYPE_INT_RGB);
            AffineTransform at = AffineTransform.getScaleInstance(FACTOR, FACTOR);
            Graphics2D g = img.createGraphics();
            g.drawRenderedImage(bi, at);
            ByteArrayOutputStream imgBytes = new ByteArrayOutputStream();
            ImageIO.write(img, "JPG", imgBytes);
            stream.clear();
            stream.setData(imgBytes.toByteArray(), false, PRStream.BEST_COMPRESSION);
            stream.put(PdfName.TYPE, PdfName.XOBJECT);
            stream.put(PdfName.SUBTYPE, PdfName.IMAGE);
            stream.put(key, value);
            stream.put(PdfName.FILTER, PdfName.DCTDECODE);
            stream.put(PdfName.WIDTH, new PdfNumber(width));
            stream.put(PdfName.HEIGHT, new PdfNumber(height));
            stream.put(PdfName.BITSPERCOMPONENT, new PdfNumber(8));
            stream.put(PdfName.COLORSPACE, PdfName.DEVICERGB);
        }
    }
    // Save altered PDF
    PdfStamper stamper = new PdfStamper(reader, new FileOutputStream(dest));
    stamper.close();
    reader.close();
}

/**
 * Main method.
 *
 * @param    args    no arguments needed
 * @throws DocumentException 
 * @throws IOException
 */
public static void main(String[] args) throws IOException, DocumentException {
    //createPdf(RESULT);
    new ResizeImage().manipulatePdf("C:/_dev_env_/TEMP/compressPDF/TRPT_135002_1470_20131212_121423.PDF", "C:/_dev_env_/TEMP/compressPDF/compressTest.pdf");
}

}
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Author: Daniel Mulcahy, 2013-12-16 18:11:07