如何将可滚动的JPanel导出到pdf文件

Question

i have design a jpanel with so many swing components with scrollable capability. i want to export whole Jpanle into pdf file.but i am not able to export whole Jpanle. I have use itext for pdf generation. My problem is that i am not able to export whole jpanel into pdf. When i export half of Jpanel components export.but half portion do not export. this is my code.

public void PrintFrameToPDF(JPanel c, File file) {
    try {           
        Document d = new Document();
        PdfWriter writer = PdfWriter.getInstance(d, new FileOutputStream("F://newfile.pdf"));
        d.open();

        PdfContentByte cb = writer.getDirectContent();
        PdfTemplate template = cb.createTemplate(800, 1600);
        Graphics2D g2d = template.createGraphics(800, 1600);
        // g2d.translate(1.0, 1.0);
        c.paintAll(g2d);
        // c.addNotify();
        // c.validate();
        g2d.dispose();
        cb.addTemplate(template, 0, 0);
        d.close();          
    } catch (Exception e) {
        //
    }
}

plz help me . tnx

Answer 1

Consider creating a java.awt.Image from the panel first (by painting the panel to an Image). You can then get an instance of com.itextpdf.text.Image using:

com.itextpdf.text.Image.getInstance(PdfWriter writer, java.awt.Image awtImage, float quality) -
Gets an instance of a com.itextpdf.textImage from a java.awt.Image . The image is added as a JPEG with a user defined quality.

Then you can scale the image with the com.itextpdf.text.Image API methods scaleToFit or scalePercent() (as used in the example below). More information on using images (in iText) can be found here

The following program create a panel of size 2000x2000 in which squares 20x20 (of 100px each) are drawn onto a panel. The panel is contained inside a scroll pane. It is then painted on to an image, where the image will be scaled and added to the pdf document and printed to pdf.

_{The below image just shows how the entire panel is drawn onto the image then another panel is created, using the previous panel image, to draw onto the the new panel. The new panel is then shown via a dialog.}

import java.awt.Color;
import java.awt.Component;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.image.BufferedImage;
import java.io.FileOutputStream;

import javax.swing.JFrame;
import javax.swing.JOptionPane;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.SwingUtilities;

import com.itextpdf.text.Document;
import com.itextpdf.text.Image;
import com.itextpdf.text.pdf.PdfWriter;

/**
 * This example requires iText. I retrieved it from Maven repository
 * 
 *      <dependency>
 *          <groupId>com.itextpdf</groupId>
 *          <artifactId>itextpdf</artifactId>
 *          <version>5.5.2</version>
 *      </dependency>
 *
 * The program can be run without iText if you comment out the entire
 * method printToPDF (and iText imports), along with it's method call in 
 * the class constructor. The result will be the the image above.
 */

public class LargePanelToImageMCVE {

    public LargePanelToImageMCVE() {
        LargeImagePanel panel = new LargeImagePanel();
        JFrame frame = new JFrame();
        frame.add(new JScrollPane(panel));
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.setExtendedState(JFrame.MAXIMIZED_BOTH);
        frame.setVisible(true);

        final java.awt.Image image = getImageFromPanel(panel);

        /* This was just a text panel to make sure the full panel was
         * drawn to the panel.
         */
        JPanel newPanel = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);
                g.drawImage(image, 0, 0, getWidth(), getHeight(), this);
            }

            @Override
            public Dimension getPreferredSize() {
                return new Dimension(300, 300);
            }
        };

        /* Print Image to PDF */
        String fileName = "D://newfile.pdf";
        printToPDF(image, fileName);

        /* This was just a test to show the newPanel drew the entire
         * original panel (scaled)
         */
        JOptionPane.showMessageDialog(null, newPanel);

    }

    public void printToPDF(java.awt.Image awtImage, String fileName) {
        try {
            Document d = new Document();
            PdfWriter writer = PdfWriter.getInstance(d, new FileOutputStream(
                    fileName));
            d.open();


            Image iTextImage = Image.getInstance(writer, awtImage, 1);
            iTextImage.setAbsolutePosition(50, 50);
            iTextImage.scalePercent(25);
            d.add(iTextImage);

            d.close();

        } catch (Exception e) {
            e.printStackTrace();
        }   
    }

    public static java.awt.Image getImageFromPanel(Component component) {

        BufferedImage image = new BufferedImage(component.getWidth(),
                component.getHeight(), BufferedImage.TYPE_INT_RGB);
        component.paint(image.getGraphics());
        return image;
    }

    /**
     * Demo panel that is 2000x2000 px with alternating squares
     * to check all squares are drawn to image
     */
    public class LargeImagePanel extends JPanel {
        private static final int FULL_SIZE = 2000;
        private static final int PER_ROW_COLUMN = 20;
        private static final int SQUARE_SIZE = FULL_SIZE / PER_ROW_COLUMN;

        protected void paintComponent(Graphics g) {
            super.paintComponent(g);
            for (int row = 0; row < PER_ROW_COLUMN; row++) {
                for (int col = 0; col < PER_ROW_COLUMN; col++) {
                    if ((row % 2) == (col % 2)) {
                        g.setColor(Color.BLACK);
                    } else {
                        g.setColor(Color.WHITE);
                    }
                    g.fillRect(col * SQUARE_SIZE, row * SQUARE_SIZE,
                            SQUARE_SIZE, SQUARE_SIZE);
                }
            }
        }

        @Override
        public Dimension getPreferredSize() {
            return new Dimension(FULL_SIZE, FULL_SIZE);
        }
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                new LargePanelToImageMCVE();
            }
        });
    }
}