001// License: GPL. For details, see LICENSE file.
002package org.openstreetmap.josm.gui.widgets;
003
004import java.awt.Dimension;
005import java.awt.LayoutManager;
006import java.awt.Rectangle;
007
008import javax.swing.JPanel;
009import javax.swing.JScrollPane;
010import javax.swing.Scrollable;
011
012import org.openstreetmap.josm.gui.util.GuiHelper;
013
014/**
015 * A panel that can be scrolled vertically. It enhances the normal {@link JPanel} to allow for better scrolling.
016 * Scroll pane contents may extend this.
017 * Use {@link #getVerticalScrollPane()} once to embed it into a scroll pane.
018 */
019public class VerticallyScrollablePanel extends JPanel implements Scrollable {
020
021    /**
022     * Constructs a new {@code VerticallyScrollablePanel}.
023     */
024    public VerticallyScrollablePanel() {
025        super();
026    }
027
028    /**
029     * Constructs a new {@code VerticallyScrollablePanel}.
030     * @param isDoubleBuffered  a boolean, true for double-buffering, which
031     *        uses additional memory space to achieve fast, flicker-free updates
032     */
033    public VerticallyScrollablePanel(boolean isDoubleBuffered) {
034        super(isDoubleBuffered);
035    }
036
037    /**
038     * Constructs a new {@code VerticallyScrollablePanel}.
039     * @param layout  the LayoutManager to use
040     * @param isDoubleBuffered  a boolean, true for double-buffering, which
041     *        uses additional memory space to achieve fast, flicker-free updates
042     */
043    public VerticallyScrollablePanel(LayoutManager layout, boolean isDoubleBuffered) {
044        super(layout, isDoubleBuffered);
045    }
046
047    /**
048     * Constructs a new {@code VerticallyScrollablePanel}.
049     * @param layout  the LayoutManager to use
050     */
051    public VerticallyScrollablePanel(LayoutManager layout) {
052        super(layout);
053    }
054
055    /**
056     * Returns a vertical scrollable {@code JScrollPane} containing this panel.
057     * @return the vertical scrollable {@code JScrollPane}
058     * @since 6666
059     */
060    public final JScrollPane getVerticalScrollPane() {
061        return GuiHelper.embedInVerticalScrollPane(this);
062    }
063
064    @Override
065    public Dimension getPreferredScrollableViewportSize() {
066        return getPreferredSize();
067    }
068
069    @Override
070    public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
071        return 20;
072    }
073
074    @Override
075    public boolean getScrollableTracksViewportHeight() {
076        return false;
077    }
078
079    @Override
080    public boolean getScrollableTracksViewportWidth() {
081        return true;
082    }
083
084    @Override
085    public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
086        return 10;
087    }
088}