Export PDF pages to a series of images in Java

Question

I need to export the pages of an arbitrary PDF document into a series of individual images in jpeg/png/etc format. I need to do this in in Java.

Although I do know about iText, PDFBox and various other java pdf libraries, I am hoping for a pointer to some working example, or some how-to.

Thanks.

Answer 1

Here is one way to do it, combining some code fragments from around the web.

How do I draw a PDF into an Image?

https://pdf-renderer.dev.java.net/examples.html

Creating a Buffered Image from an Image

http://www.exampledepot.com/egs/java.awt.image/Image2Buf.html

Saving a Generated Graphic to a PNG or JPEG File

http://www.exampledepot.com/egs/javax.imageio/Graphic2File.html

Combined together into something that works like this to turn all the pages into images:

import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFPage;
import java.awt.Image;
import java.awt.Rectangle;
import java.io.*;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import javax.swing.*;
import javax.imageio.*;
import java.awt.image.*;

public class ImageMain {

public static void setup() throws IOException {

    //load a pdf from a byte buffer
    File file = new File("test.pdf");
    RandomAccessFile raf = new RandomAccessFile(file, "r");
    FileChannel channel = raf.getChannel();
    ByteBuffer buf = channel.map(FileChannel.MapMode.READ_ONLY, 0, channel.size());
    PDFFile pdffile = new PDFFile(buf);

    int numPgs = pdffile.getNumPages();


   for (int i=0; i<numPgs; i++)
   {
   // draw the first page to an image
    PDFPage page = pdffile.getPage(i);

    //get the width and height for the doc at the default zoom 
    Rectangle rect = new Rectangle(0,0,
            (int)page.getBBox().getWidth(),
            (int)page.getBBox().getHeight());

    //generate the image
    Image img = page.getImage(
            rect.width, rect.height, //width & height
            rect, // clip rect
            null, // null for the ImageObserver
            true, // fill background with white
            true  // block until drawing is done
            );


    //save it as a file
    BufferedImage bImg = toBufferedImage( img );
    File yourImageFile = new File("page_" + i + ".png");
    ImageIO.write( bImg,"png",yourImageFile);
    }
}


// This method returns a buffered image with the contents of an image
public static BufferedImage toBufferedImage(Image image) {
    if (image instanceof BufferedImage) {
        return (BufferedImage)image;
    }

    // This code ensures that all the pixels in the image are loaded
    image = new ImageIcon(image).getImage();

    // Determine if the image has transparent pixels; for this method's
    // implementation, see e661 Determining If an Image Has Transparent Pixels
    boolean hasAlpha = hasAlpha(image);

    // Create a buffered image with a format that's compatible with the screen
    BufferedImage bimage = null;
    GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
    try {
        // Determine the type of transparency of the new buffered image
        int transparency = Transparency.OPAQUE;
        if (hasAlpha) {
            transparency = Transparency.BITMASK;
        }

        // Create the buffered image
        GraphicsDevice gs = ge.getDefaultScreenDevice();
        GraphicsConfiguration gc = gs.getDefaultConfiguration();
        bimage = gc.createCompatibleImage(
            image.getWidth(null), image.getHeight(null), transparency);
    } catch (HeadlessException e) {
        // The system does not have a screen
    }

    if (bimage == null) {
        // Create a buffered image using the default color model
        int type = BufferedImage.TYPE_INT_RGB;
        if (hasAlpha) {
            type = BufferedImage.TYPE_INT_ARGB;
        }
        bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
    }

    // Copy image to buffered image
    Graphics g = bimage.createGraphics();

    // Paint the image onto the buffered image
    g.drawImage(image, 0, 0, null);
    g.dispose();

    return bimage;
}

public static void main(final String[] args) {
    SwingUtilities.invokeLater(new Runnable() {
        public void run() {
            try {
                ImageMain.setup();
            } catch (IOException ex) {
                ex.printStackTrace();
            }
        }
    });
}
}

Answer 2

If you consider the JPedal PDF library, its built in and documented with eample source at http://support.idrsolutions.com/default.asp?W22

Answer 3

Hi,

I was looking for similar kind of solution for myself. When I tried the same example with a pdf file with more than 1 page, all output png files are coming for first page only. Any idea whats wrong here.

Thanks, Abhi

Answer 4

hi.

jst start your for loop from 1 instead of 0...Your problem will be solved..

cheers, Ravie