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

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

UPDATED: How to convert buffered image to image and vice-versa?

Saving a Generated Graphic to a PNG or JPEG File

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

UPDATED: http://docs.oracle.com/javase/tutorial/2d/images/saveimage.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.Graphics; import java.awt.GraphicsConfiguration; import java.awt.GraphicsDevice; import java.awt.GraphicsEnvironment; import java.awt.HeadlessException; import java.awt.Image; import java.awt.Rectangle; import java.awt.Transparency; 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 boolean hasAlpha(Image image) {         // If buffered image, the color model is readily available         if (image instanceof BufferedImage) {             BufferedImage bimage = (BufferedImage) image;             return bimage.getColorModel().hasAlpha();         }         // Use a pixel grabber to retrieve the image's color model;         // grabbing a single pixel is usually sufficient         PixelGrabber pg = new PixelGrabber(image, 0, 0, 1, 1, false);         try {             pg.grabPixels();         } catch (InterruptedException e) {         }         // Get the image's color model         ColorModel cm = pg.getColorModel();         return cm.hasAlpha();     }      public static void main(final String[] args) {         SwingUtilities.invokeLater(new Runnable() {             public void run() {                 try {                     ImageMain.setup();                 } catch (IOException ex) {                     ex.printStackTrace();                 }             }         });     } }