com.languageExplorer.widgets.ScrollableBarUI Maven / Gradle / Ivy

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/*
 * ===========================================================================
 * Copyright 2004 by Volker H. Simonis. All rights reserved.
 * ===========================================================================
 */
package com.languageExplorer.widgets;

import java.awt.Component;
import java.awt.Container;
import java.awt.Dimension;
import java.awt.Graphics;
import java.awt.LayoutManager;
import java.awt.Point;

import java.awt.event.MouseEvent;
import java.awt.event.MouseListener;
import java.awt.event.MouseWheelEvent;
import java.awt.event.MouseWheelListener;

import java.beans.PropertyChangeEvent;
import java.beans.PropertyChangeListener;

import javax.swing.BoxLayout;
import javax.swing.JButton;
import javax.swing.JComponent;
import javax.swing.JViewport;
import javax.swing.SwingConstants;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.ViewportLayout;

import javax.swing.plaf.ComponentUI;

import javax.swing.event.ChangeEvent;
import javax.swing.event.ChangeListener;

public class ScrollableBarUI extends ComponentUI 
implements SwingConstants, 
MouseListener,
ChangeListener, 
PropertyChangeListener {

	private ScrollableBar sb;
	private JViewport scroll;
	private JButton scrollF, scrollB;
	private boolean pressed = false;
	private int inc;

	public static ComponentUI createUI(JComponent c) {
		return new ScrollableBarUI();
	}

	// BEGIN installUI
	public void installUI(JComponent c) {

		sb = (ScrollableBar)c;

		inc = sb.getIncrement();
		boolean small = sb.isSmallArrows();

		// Create the Buttons
		int sbSize = ((Integer)(UIManager.get( "ScrollBar.width" ))).intValue();
		scrollB = createButton(sb.isHorizontal()?WEST:NORTH, sbSize, small);
		scrollB.setVisible(false);
		scrollB.addMouseListener(this);

		scrollF = createButton(sb.isHorizontal()?EAST:SOUTH, sbSize, small);
		scrollF.setVisible(false);
		scrollF.addMouseListener(this);

		sb.addMouseWheelListener(new MouseWheelListener() {
			@Override
			public void mouseWheelMoved(MouseWheelEvent e) {
				if (e.getWheelRotation()!=0){
					if (e.getWheelRotation()>0){
						for (int k=0;ke.getWheelRotation();k--){
							SwingUtilities.invokeLater(
									new Runnable(){
										public void run(){
											processEvent(scrollF);
										}
									});
						}
					}
				}
			}
		});

		int axis = sb.isHorizontal()?BoxLayout.X_AXIS:BoxLayout.Y_AXIS;
		sb.setLayout(new BoxLayout(sb, axis));

		scroll = new JViewport() {
			// ... "see source code"
			// Create a customized layout manager
			protected LayoutManager createLayoutManager() {
				return new ViewportLayout() {
					public Dimension minimumLayoutSize(Container parent) {
						Component view = ((JViewport)parent).getView();
						if (view == null) {
							return new Dimension(4, 4);
						}
						else {
							Dimension d = view.getPreferredSize();
							if (sb.isHorizontal()) {
								return new Dimension(4, (int)d.getHeight());
							}
							else {
								return new Dimension((int)d.getWidth(), 4);
							}
						}  
					}
				};
			}
			// ...
		};

		Component box = sb.getComponent();
		scroll.setView(box);

		sb.add(scrollB);
		sb.add(scroll);
		sb.add(scrollF);

		// Install the change listeners
		scroll.addChangeListener(this);
		sb.addPropertyChangeListener(this);
	}
	// END installUI

	public void uninstallUI(JComponent c) {
		// Remove the change listeners
		scroll.removeChangeListener(this);
		sb.removePropertyChangeListener(this);
	}

	protected JButton createButton(int direction, int width, boolean small) {
		JButton button = new ScrollButton(direction, width, small);
		button.setAlignmentX(0.5f);
		button.setAlignmentY(0.5f);
		return button;
	}

	// PropertyChangeListner methods.

	public void propertyChange(PropertyChangeEvent evt) {
		if ("increment".equals(evt.getPropertyName())) {
			inc = ((Integer)evt.getNewValue()).intValue();
		}
		else if ("smallArrows".equals(evt.getPropertyName())) {
			boolean small = ((Boolean)evt.getNewValue()).booleanValue();
			((ScrollButton)scrollB).setSmallArrows(small);
			((ScrollButton)scrollF).setSmallArrows(small);
		}
		else if ("component".equals(evt.getPropertyName())) {
			scroll.setView((Component)evt.getNewValue());
		}
	}

	// ChangeListner methods.

	public void stateChanged(ChangeEvent e) {
		boolean cond = sb.isHorizontal() ?
				sb.getWidth() < scroll.getViewSize().width:
					sb.getHeight() < scroll.getViewSize().height;
				if (cond) {
					scrollB.setVisible(true);
					scrollF.setVisible(true);
				}
				else {
					scrollB.setVisible(false);
					scrollF.setVisible(false);
					sb.doLayout();
				}
	}

	// MouseListener methods.

	public void mouseClicked(MouseEvent e) {
	}

	public void mouseEntered(MouseEvent e) {
	}

	// BEGIN mouseRelease
	public void mouseExited(MouseEvent e) {
		pressed = false;
	}

	public void mouseReleased(MouseEvent e) {
		pressed = false;
	}
	// END mouseRelease

	// BEGIN mousePressed
	public void mousePressed(MouseEvent e) {
		pressed = true;
		final Object o = e.getSource();
		Thread scroller = new Thread(new Runnable() {
			public void run() {
				int accl = 500;
				boolean processed=false;
				while (pressed && !processed) {          
					// ... "Compute new view position"
					processed=    processEvent(o);
					try {
						Thread.sleep(accl);
						if (accl <= 10) accl = 10;
						else accl /= 2;
					} catch (InterruptedException ie) {}
				}
			}
		});
		scroller.start();
	}

	private boolean  processEvent(final Object o) {
		Point p = scroll.getViewPosition();
		if (sb.isHorizontal()) {
			if (o == scrollB) {
				p.x -= inc;
				if (p.x < 0) {
					p.x = 0;
					scroll.setViewPosition(p);
					return true;
				}
			}
			else {
				if (scroll.getViewSize().width - p.x - 
						scroll.getExtentSize().width > inc) {
					p.x += inc;
					scroll.setViewPosition(p);
					return false;
				}else {
					p.x = scroll.getViewSize().width - 
							scroll.getExtentSize().width;
					scroll.setViewPosition(p);
					return true;
				}
			}
		}
		else {
			if (o == scrollB) {
				p.y -= inc;
				if (p.y < 0) {
					p.y = 0;
					scroll.setViewPosition(p);
					return true;
				} else {
					scroll.setViewPosition(p);
					return false;
				}

			} else

				if (scroll.getViewSize().height - p.y - 
						scroll.getExtentSize().height > inc) {
					p.y += inc;
					scroll.setViewPosition(p);
					return false;
				} else {
					p.y = scroll.getViewSize().height - 
							scroll.getExtentSize().height;
					scroll.setViewPosition(p);
					return true;
				}

		}
		return true;
	}
}


// END mousePressed