pdfscrollpane.java

Java生成PDF Java生成PDF Java生成PDF

// $Id: PDFScrollPane.java,v 1.18 2006/09/28 14:38:07 mike Exp $

package org.faceless.pdf2.viewer;

import org.faceless.pdf2.PDF;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;

/**
 * <p>
 * The <code>PDFScrollPane</code> provides a scrollable view of a PDF document.
 * A <code>PDFScrollPane</code> manages a viewport, horizontal and vertical scroll bars.
 * Note that <code>PDFScrollPane</code> can only contain {@link PDF} objects.
 * </p><p>
 * Initially <code>PDFScrollPane</code>'s viewport is empty - here is an example of how
 * to initialise the <code>PDFViewport</code> to display {@link PDF} objects.</p>
 * </p><pre class=example>
 * PDF pdf = loadMyPDF();       // Create your PDF somehow (probably from a PDFReader)
 * PDFScrollPane scrollpane = new PDFScrollPane();
 * PDFViewport viewport = scrollpane.getViewport();
 * viewport.setDocument(pdf);
 * </pre>
 * <p>This PDF scrollable view can be incorporated in to any Swing application.</p>
 * <p><i>
 * This code is copyright the Big Faceless Organization. You're welcome to
 * use, modify and distribute it in any form in your own projects, provided
 * those projects continue to make use of the Big Faceless PDF library.
 * </i></p>
 *
 * @since 2.5
 */
public class PDFScrollPane extends JPanel implements PDFViewport.ViewportObserver
{
    private JScrollBar sbv, sbh;                // Vertical/Horizontal scrollbars
    private PDFViewport view;

    /**
     * Creates a new, empty PDF scroll pane.
     */
    public PDFScrollPane() {
        this(new PDFViewport());
    }

    /**
     * Creates a new, empty PDF scroll pane with the
     * specified {@link PDFViewport}.
     * @param viewport the viewport to use in this scrollpane
     * @since 2.7.3
     */
    public PDFScrollPane(PDFViewport viewport) {
        super();

        setDoubleBuffered(true);
        addComponentListener(new PDFPaneListener());

        sbv = new JScrollBar(JScrollBar.VERTICAL);
        sbh = new JScrollBar(JScrollBar.HORIZONTAL);
        addMouseWheelListener(new VerticalWheelListener());

        sbh.setMinimum(0);
        sbh.setBlockIncrement(15);
        sbh.setUnitIncrement(15);
        sbh.addAdjustmentListener(new HorizontalListener());

        sbv.setMinimum(0);
        sbv.setBlockIncrement(15);
        sbv.setUnitIncrement(15);
        sbv.addAdjustmentListener(new VerticalListener());

        setLayout(new BorderLayout());
        sbv.setVisible(true);
        sbh.setVisible(true);

        this.view = viewport;
        view.addObserver(this);
        add(view, BorderLayout.CENTER);
        add(sbv, BorderLayout.EAST);
        add(sbh, BorderLayout.SOUTH);
    }

    public void viewportChanged(double x, double y) {
        final int sx = (int)x;
        final int sy = (int)y;

        Runnable UpdateBars = new Runnable() {
            public void run() {
                sbh.setMaximum(view.getPageWidth());
                sbv.setMaximum(view.getPageHeight());
                sbh.setValue(sx);
                sbv.setValue(sy);
                sbh.setVisibleAmount((int)view.getVisibleWidth());
                sbv.setVisibleAmount((int)view.getVisibleHeight());
            }
        };
        SwingUtilities.invokeLater(UpdateBars);
    }

    /**
     * Returns the current {@link PDFViewport}.
     *
     * @return the viewport property
     */
    public PDFViewport getViewport() {
        return view;
    }

    class VerticalListener implements AdjustmentListener {
        public void adjustmentValueChanged(AdjustmentEvent e) {
            view.setViewPosition(sbh.getValue(), sbv.getValue());
        }
    }

    class HorizontalListener implements AdjustmentListener {
        public void adjustmentValueChanged(AdjustmentEvent e) {
            view.setViewPosition(sbh.getValue(), sbv.getValue());
        }
    }

    class PDFPaneListener extends ComponentAdapter {
        public void componentResized(ComponentEvent e) {
            int sx = (int)Math.min(view.getMaxScrollX(), sbh.getValue());
            int sy = (int)Math.min(view.getMaxScrollY(), sbv.getValue());
            sbh.setValue(sx);
            sbv.setValue(sy);

            view.setViewPosition(sbh.getValue(), sbv.getValue());

            Runnable UpdateBars = new Runnable() {
                public void run() {
                    sbh.setVisibleAmount((int)view.getVisibleWidth());
                    sbv.setVisibleAmount((int)view.getVisibleHeight());
                }
            };
            SwingUtilities.invokeLater(UpdateBars);
        }

    }

    class VerticalWheelListener implements MouseWheelListener {
        public void mouseWheelMoved(MouseWheelEvent e) {
            if (e.getScrollType() == MouseWheelEvent.WHEEL_UNIT_SCROLL) {
                int totalScrollAmount = e.getUnitsToScroll() * sbv.getUnitIncrement();
                sbv.setValue(sbv.getValue() + totalScrollAmount);
            }
        }

    }

    public void writeAsTIFFComplete() { }
}