PDFViewer.java

/*
    Copyright (C) 2013  Tobias Baum <tbaum at tntinteractive.de>

    This file is a part of Portalsammler.

    Portalsammler is free software: you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation, either version 3 of the License, or
    (at your option) any later version.

    Portalsammler is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with Portalsammler.  If not, see <http://www.gnu.org/licenses/>.
 */
package de.tntinteractive.portalsammler.gui;

import java.awt.Image;
import java.awt.Rectangle;
import java.awt.Toolkit;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.geom.Rectangle2D;

import javax.swing.ImageIcon;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;

import com.jgoodies.forms.builder.ButtonBarBuilder;
import com.jgoodies.forms.builder.PanelBuilder;
import com.jgoodies.forms.factories.CC;
import com.jgoodies.forms.layout.FormLayout;
import com.sun.pdfview.PDFFile;
import com.sun.pdfview.PDFPage;

public class PDFViewer extends JFrame {

    private static final long serialVersionUID = 843311728636015602L;

    private final PDFFile pdfFile;
    private int currentPage;
    private final JLabel posLabel;
    private final JLabel contentLabel;

    public PDFViewer(final String title, final PDFFile pdfFile) {
        super(title);

        this.pdfFile = pdfFile;
        this.currentPage = 1;

        this.contentLabel = new JLabel();
        this.contentLabel.setVerticalAlignment(JLabel.TOP);
        final JScrollPane scrollPane = new JScrollPane(this.contentLabel);

        final JButton backwardButton = new JButton("<");
        backwardButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(final ActionEvent e) {
                PDFViewer.this.backward();
            }
        });
        this.posLabel = new JLabel();
        final JButton forwardButton = new JButton(">");
        forwardButton.addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(final ActionEvent e) {
                PDFViewer.this.forward();
            }
        });

        final ButtonBarBuilder bbb = new ButtonBarBuilder();
        bbb.addButton(backwardButton, this.posLabel, forwardButton);

        this.showCurrentPage();

        final PanelBuilder builder = new PanelBuilder(new FormLayout(
                "4dlu, p, 4dlu",
                "4dlu, fill:300dlu:grow, 4dlu, p, 4dlu"));
        builder.add(scrollPane, CC.xy(2, 2));
        builder.add(bbb.getPanel(), CC.xy(2, 4));
        this.setContentPane(builder.getPanel());

        this.pack();
    }

    private void backward() {
        if (this.currentPage > 1) {
            this.currentPage--;
            this.showCurrentPage();
        }
    }

    private void forward() {
        if (this.currentPage < this.pdfFile.getNumPages()) {
            this.currentPage++;
            this.showCurrentPage();
        }
    }

    private void showCurrentPage() {
        this.posLabel.setText(this.currentPage + " / " + this.pdfFile.getNumPages());

        final PDFPage page = this.pdfFile.getPage(this.currentPage);

        final Rectangle2D r2d = page.getBBox();
        double width = r2d.getWidth();
        double height = r2d.getHeight();
        width /= 72.0;
        height /= 72.0;
        final int res = Toolkit.getDefaultToolkit().getScreenResolution();
        width *= res;
        height *= res;

        final Image image = page.getImage((int) width, (int) height, r2d, null, true, true);
        final ImageIcon icon = new ImageIcon(image);
        this.contentLabel.setIcon(icon);
        this.validate();

        this.contentLabel.scrollRectToVisible(
                new Rectangle(icon.getIconWidth() / 4, icon.getIconHeight() / 4, 1, 1));
    }

}