Monday, March 2, 2015

Generate PDF page as image

We can generate the image of pdf page by using the Pdf-renderer

Simple class which generate the images file of given pdf file.

/*
 * To change this license header, choose License Headers in Project Properties.
 * To change this template file, choose Tools | Templates
 * and open the template in the editor.
 */
package mayan.pdf;

/**
 *
 * @author Uttesh Kumar T.H.
 */
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.awt.image.*;
import java.io.*;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import javax.imageio.*;
import javax.swing.*;

public class PdfPageImageGenerator {

    public static void ImageGenerator() throws IOException {
        // load a pdf from a byte buffer
        File file = new File("sample.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++) {
            PDFPage page = pdffile.getPage(i);
            Rectangle rect = new Rectangle(0, 0, (int) page.getBBox().getWidth(), (int) page.getBBox().getHeight());
            Image img = page.getImage(rect.width, rect.height, rect, null, true, true);
            BufferedImage bImg = toBufferedImage(img);
            File yourImageFile = new File("pics\\page_" + i + ".png");
            ImageIO.write(bImg, "png", yourImageFile);
        }
    }

    public static BufferedImage toBufferedImage(Image image) {
        if (image instanceof BufferedImage) {
            return (BufferedImage) image;
        }
        image = new ImageIcon(image).getImage();
        boolean hasAlpha = hasAlpha(image);
        BufferedImage bimage = null;
        GraphicsEnvironment ge = GraphicsEnvironment.getLocalGraphicsEnvironment();
        try {
            int transparency = Transparency.OPAQUE;
            if (hasAlpha) {
                transparency = Transparency.BITMASK;
            }
            GraphicsDevice gs = ge.getDefaultScreenDevice();
            GraphicsConfiguration gc = gs.getDefaultConfiguration();
            bimage = gc.createCompatibleImage(image.getWidth(null), image.getHeight(null), transparency);
        } catch (HeadlessException e) {
        }
        if (bimage == null) {
            int type = BufferedImage.TYPE_INT_RGB;
            if (hasAlpha) {
                type = BufferedImage.TYPE_INT_ARGB;
            }
            bimage = new BufferedImage(image.getWidth(null), image.getHeight(null), type);
        }
        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 (image instanceof BufferedImage) {
            BufferedImage bimage = (BufferedImage) image;
            return bimage.getColorModel().hasAlpha();
        }
        PixelGrabber pg = new PixelGrabber(image, 0, 0, 1, 1, false);
        try {
            pg.grabPixels();
        } catch (InterruptedException e) {
        }
        ColorModel cm = pg.getColorModel();
        return cm.hasAlpha();
    }

    public static void main(final String[] args) {
        new Runnable() {
            public void run() {
                try {
                    PdfPageImageGenerator.ImageGenerator();
                } catch (IOException ex) {
                    ex.printStackTrace();
                }
            }
        }.run();
    }
}


formatted view of above code



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