components.ScrollablePicture.java Source code

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Here is the source code for components.ScrollablePicture.java

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/*
 * Copyright (c) 1995, 2008, Oracle and/or its affiliates. All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   - Redistributions of source code must retain the above copyright
 *     notice, this list of conditions and the following disclaimer.
 *
 *   - Redistributions in binary form must reproduce the above copyright
 *     notice, this list of conditions and the following disclaimer in the
 *     documentation and/or other materials provided with the distribution.
 *
 *   - Neither the name of Oracle or the names of its
 *     contributors may be used to endorse or promote products derived
 *     from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS
 * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
 * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
 * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

package components;

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
import javax.swing.border.*;

/* ScrollablePicture.java is used by ScrollDemo.java. */

public class ScrollablePicture extends JLabel implements Scrollable, MouseMotionListener {

    private int maxUnitIncrement = 1;
    private boolean missingPicture = false;

    public ScrollablePicture(ImageIcon i, int m) {
        super(i);
        if (i == null) {
            missingPicture = true;
            setText("No picture found.");
            setHorizontalAlignment(CENTER);
            setOpaque(true);
            setBackground(Color.white);
        }
        maxUnitIncrement = m;

        //Let the user scroll by dragging to outside the window.
        setAutoscrolls(true); //enable synthetic drag events
        addMouseMotionListener(this); //handle mouse drags
    }

    //Methods required by the MouseMotionListener interface:
    public void mouseMoved(MouseEvent e) {
    }

    public void mouseDragged(MouseEvent e) {
        //The user is dragging us, so scroll!
        Rectangle r = new Rectangle(e.getX(), e.getY(), 1, 1);
        scrollRectToVisible(r);
    }

    public Dimension getPreferredSize() {
        if (missingPicture) {
            return new Dimension(320, 480);
        } else {
            return super.getPreferredSize();
        }
    }

    public Dimension getPreferredScrollableViewportSize() {
        return getPreferredSize();
    }

    public int getScrollableUnitIncrement(Rectangle visibleRect, int orientation, int direction) {
        //Get the current position.
        int currentPosition = 0;
        if (orientation == SwingConstants.HORIZONTAL) {
            currentPosition = visibleRect.x;
        } else {
            currentPosition = visibleRect.y;
        }

        //Return the number of pixels between currentPosition
        //and the nearest tick mark in the indicated direction.
        if (direction < 0) {
            int newPosition = currentPosition - (currentPosition / maxUnitIncrement) * maxUnitIncrement;
            return (newPosition == 0) ? maxUnitIncrement : newPosition;
        } else {
            return ((currentPosition / maxUnitIncrement) + 1) * maxUnitIncrement - currentPosition;
        }
    }

    public int getScrollableBlockIncrement(Rectangle visibleRect, int orientation, int direction) {
        if (orientation == SwingConstants.HORIZONTAL) {
            return visibleRect.width - maxUnitIncrement;
        } else {
            return visibleRect.height - maxUnitIncrement;
        }
    }

    public boolean getScrollableTracksViewportWidth() {
        return false;
    }

    public boolean getScrollableTracksViewportHeight() {
        return false;
    }

    public void setMaxUnitIncrement(int pixels) {
        maxUnitIncrement = pixels;
    }
}