can JViewport Scroll - Java Swing

Java examples for Swing:JViewport

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Description

can JViewport Scroll

Demo Code

/**//from w  ww .j a  v a 2s. co  m
 * MySwing: Advanced Swing Utilites
 * Copyright (C) 2005  Santhosh Kumar T
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library 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
 * Lesser General Public License for more details.
 */
//package com.java2s;
import javax.swing.*;
import java.awt.*;

public class Main {
    public static boolean canScroll(JViewport viewport) {
        return canHScroll(viewport) || canVScroll(viewport);
    }

    public static boolean canHScroll(JViewport viewport) {
        JScrollPane scrollPane = (JScrollPane) viewport.getParent();
        Rectangle availR = scrollPane.getBounds();

        Component view = viewport.getView();
        Dimension viewPrefSize = view != null ? view.getPreferredSize()
                : new Dimension(0, 0);
        Dimension extentSize = viewport.toViewCoordinates(availR.getSize());

        boolean canHScroll = true;
        if (view instanceof Scrollable)
            canHScroll = !((Scrollable) view)
                    .getScrollableTracksViewportWidth();
        if (canHScroll && (viewPrefSize.width <= extentSize.width))
            canHScroll = false;

        return canHScroll;
    }

    public static boolean canVScroll(JViewport viewport) {
        JScrollPane scrollPane = (JScrollPane) viewport.getParent();
        Rectangle availR = scrollPane.getBounds();

        Component view = viewport.getView();
        Dimension viewPrefSize = view != null ? view.getPreferredSize()
                : new Dimension(0, 0);
        Dimension extentSize = viewport.toViewCoordinates(availR.getSize());

        boolean canVScroll = true;
        if (view instanceof Scrollable)
            canVScroll = !((Scrollable) view)
                    .getScrollableTracksViewportHeight();
        if (canVScroll && (viewPrefSize.height <= extentSize.height))
            canVScroll = false;

        return canVScroll;
    }
}

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