org.mihalis.opal/src/main/java/org/mihalis/opal/obutton/OButton.java - osbp/org.eclipse.osbp.fork.mihalis.opal.imageSelector.osgi - Git at Google

 /*******************************************************************************
  * Copyright (c) 2012 Laurent CARON
  * All rights reserved. This program and the accompanying materials
  * are made available under the terms of the Eclipse Public License v1.0
  * which accompanies this distribution, and is available at
  * http://www.eclipse.org/legal/epl-v10.html
  *
  * Contributors:
  *     Laurent CARON (laurent.caron at gmail dot com) - initial API and implementation
  *******************************************************************************/
 package org.mihalis.opal.obutton;

 import java.util.ArrayList;
 import java.util.List;

 import org.eclipse.swt.SWT;
 import org.eclipse.swt.SWTException;
 import org.eclipse.swt.events.SelectionEvent;
 import org.eclipse.swt.events.SelectionListener;
 import org.eclipse.swt.graphics.Image;
 import org.eclipse.swt.graphics.Point;
 import org.eclipse.swt.widgets.Canvas;
 import org.eclipse.swt.widgets.Composite;
 import org.eclipse.swt.widgets.Event;
 import org.eclipse.swt.widgets.Listener;
 import org.eclipse.swt.widgets.Widget;

 /**
  * Instances of this class represent a selectable user interface object that issues notification when pressed and released.
  * <dl>
  * <dt><b>Styles:</b></dt>
  * <dd>ARROW, PUSH, TOGGLE</dd>
  * <dd>UP, DOWN, LEFT, RIGHT, CENTER</dd>
  * <dt><b>Events:</b></dt>
  * <dd>Selection</dd>
  * </dl>
  * <p>
  * Note: Only one of the styles ARROW, PUSH and TOGGLE may be specified.
  * </p>
  * <p>
  * Note: Only one of the styles LEFT, RIGHT, and CENTER may be specified.
  * </p>
  * <p>
  * Note: Only one of the styles UP, DOWN, LEFT, and RIGHT may be specified when the ARROW style is specified.
  * </p>
  */
 public class OButton extends Canvas {

 	/** The Constant IS_BUTTON_PRESSED. */
 	private static final String IS_BUTTON_PRESSED = OButton.class.toString() + "_pressed";

 	/** The selection listeners. */
 	private final List<SelectionListener> selectionListeners;

 	/** The alignment. */
 	int alignment = SWT.LEFT;

 	/** The button renderer. */
 	private ButtonRenderer buttonRenderer;

 	/** The selected. */
 	boolean selected;

 	/** The hover. */
 	boolean hover;

 	/** The text. */
 	String text;

 	/** The image. */
 	Image image;

 	/** The width. */
 	private int width;

 	/** The height. */
 	private int height;

 	/** The clicked. */
 	private boolean clicked;

 	/**
 	 * Constructs a new instance of this class given its parent and a style
 	 * value describing its behavior and appearance.
 	 * <p>
 	 * The style value is either one of the style constants defined in class
 	 * <code>SWT</code> which is applicable to instances of this class, or must
 	 * be built by <em>bitwise OR</em>'ing together (that is, using the
 	 * <code>int</code> "|" operator) two or more of those <code>SWT</code>
 	 * style constants. The class description lists the style constants that are
 	 * applicable to the class. Style bits are also inherited from superclasses.
 	 * </p>
 	 *
 	 * @param parent a composite control which will be the parent of the new
 	 *            instance (cannot be null)
 	 * @param style the style of control to construct
 	 * @see SWT#ARROW
 	 * @see SWT#CHECK
 	 * @see SWT#PUSH
 	 * @see SWT#RADIO
 	 * @see SWT#TOGGLE
 	 * @see SWT#FLAT
 	 * @see SWT#UP
 	 * @see SWT#DOWN
 	 * @see SWT#LEFT
 	 * @see SWT#RIGHT
 	 * @see SWT#CENTER
 	 * @see Widget#checkSubclass
 	 * @see Widget#getStyle
 	 * @exception IllegalArgumentException <ul>
 	 *                <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 	 *                </ul>
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
 	 *                thread that created the parent</li>
 	 *                <li>ERROR_INVALID_SUBCLASS - if this class is not an
 	 *                allowed subclass</li>
 	 *                </ul>
 	 */
 	public OButton(final Composite parent, final int style) {
 		super(parent, checkStyle(style) | SWT.DOUBLE_BUFFERED);
 		this.selectionListeners = new ArrayList<SelectionListener>();
 		this.buttonRenderer = DefaultButtonRenderer.getInstance();
 		this.width = this.height = -1;
 		addListeners();
 	}

 	/**
 	 * Check style.
 	 *
 	 * @param style the style
 	 * @return the int
 	 */
 	private static int checkStyle(int style) {
 		style = checkBits(style, SWT.PUSH, SWT.ARROW, SWT.TOGGLE, 0);
 		if ((style & (SWT.PUSH | SWT.TOGGLE)) != 0) {
 			return checkBits(style, SWT.CENTER, SWT.LEFT, SWT.RIGHT, 0);
 		}
 		if ((style & SWT.ARROW) != 0) {
 			return checkBits(style, SWT.UP, SWT.DOWN, SWT.LEFT, SWT.RIGHT);
 		}
 		return style;
 	}

 	/**
 	 * Check bits.
 	 *
 	 * @param style the style
 	 * @param int0 the int0
 	 * @param int1 the int1
 	 * @param int2 the int2
 	 * @param int3 the int3
 	 * @return the int
 	 */
 	private static int checkBits(int style, final int int0, final int int1, final int int2, final int int3) {
 		final int mask = int0 | int1 | int2 | int3;
 		if ((style & mask) == 0) {
 			style |= int0;
 		}
 		if ((style & int0) != 0) {
 			style = style & ~mask | int0;
 		}
 		if ((style & int1) != 0) {
 			style = style & ~mask | int1;
 		}
 		if ((style & int2) != 0) {
 			style = style & ~mask | int2;
 		}
 		if ((style & int3) != 0) {
 			style = style & ~mask | int3;
 		}
 		return style;
 	}

 	/**
 	 * Adds the listeners.
 	 */
 	private void addListeners() {
 		final Listener listener = new Listener() {

 			@Override
 			public void handleEvent(final Event event) {
 				switch (event.type) {
 					case SWT.MouseEnter:
 						OButton.this.hover = true;
 						redraw();
 						update();
 						break;
 					case SWT.MouseExit:
 						OButton.this.hover = false;
 						redraw();
 						update();
 						break;
 					case SWT.MouseDown:
 						OButton.this.clicked = true;
 						OButton.this.setData(IS_BUTTON_PRESSED, "*");
 						redraw();
 						update();
 						break;
 					case SWT.MouseUp:
 						if (OButton.this.getData(IS_BUTTON_PRESSED) == null) {
 							return;
 						}
 						OButton.this.setData(IS_BUTTON_PRESSED, null);
 						OButton.this.clicked = false;
 						OButton.this.selected = !OButton.this.selected;
 						redraw();
 						update();
 						fireSelectionEvent();
 						break;
 					case SWT.Paint:
 						handlePaintEvent(event);
 						break;
 					case SWT.KeyDown:
 						if (event.keyCode == SWT.TAB) {
 							if (event.stateMask == SWT.SHIFT) {
 								OButton.this.traverse(SWT.TRAVERSE_TAB_PREVIOUS);
 							} else {
 								OButton.this.traverse(SWT.TRAVERSE_TAB_NEXT);
 							}
 						}
 						break;
 					case SWT.Dispose:
 						OButton.this.buttonRenderer.dispose();
 						break;

 				}

 			}
 		};

 		final int[] events = new int[] { SWT.MouseEnter, SWT.MouseExit, SWT.MouseDown, SWT.MouseUp, SWT.Paint, SWT.Dispose };
 		for (final int event : events) {
 			addListener(event, listener);
 		}
 	}

 	/**
 	 * Fire selection event.
 	 */
 	protected void fireSelectionEvent() {
 		final Event event = new Event();
 		event.widget = this;
 		event.display = getDisplay();
 		event.type = SWT.Selection;
 		for (final SelectionListener selectionListener : this.selectionListeners) {
 			selectionListener.widgetSelected(new SelectionEvent(event));
 		}
 	}

 	/**
 	 * Handle paint event.
 	 *
 	 * @param event the event
 	 */
 	private void handlePaintEvent(final Event event) {
 		if (!isEnabled()) {
 			this.buttonRenderer.drawButtonWhenDisabled(event.gc, this);
 			return;
 		}

 		if (this.clicked) {
 			this.buttonRenderer.drawButtonWhenClicked(event.gc, this);
 			return;
 		}

 		if (this.hover) {
 			this.buttonRenderer.drawButtonWhenMouseHover(event.gc, this);
 			return;
 		}

 		final boolean isToggleButton = (getStyle() & SWT.TOGGLE) == SWT.TOGGLE;
 		if (isToggleButton && this.selected) {
 			this.buttonRenderer.drawButtonWhenSelected(event.gc, this);
 			return;
 		}

 		this.buttonRenderer.drawButton(event.gc, this);
 	}

 	/**
 	 * Adds the listener to the collection of listeners who will be notified
 	 * when the control is selected by the user, by sending it one of the
 	 * messages defined in the <code>SelectionListener</code> interface.
 	 * <p>
 	 * <code>widgetSelected</code> is called when the control is selected by the
 	 * user. <code>widgetDefaultSelected</code> is not called.
 	 * </p>
 	 *
 	 * @param listener the listener which should be notified
 	 * @see SelectionListener
 	 * @see #removeSelectionListener
 	 * @see SelectionEvent
 	 * @exception IllegalArgumentException <ul>
 	 *                <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 	 *                </ul>
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been
 	 *                disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
 	 *                thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void addSelectionListener(final SelectionListener listener) {
 		checkWidget();
 		if (listener == null) {
 			SWT.error(SWT.ERROR_NULL_ARGUMENT);
 		}
 		this.selectionListeners.add(listener);
 	}

 	/**
 	 * Compute size.
 	 *
 	 * @param wHint the w hint
 	 * @param hHint the h hint
 	 * @param changed the changed
 	 * @return the point
 	 * @see org.eclipse.swt.widgets.Composite#computeSize(int, int, boolean)
 	 */
 	@Override
 	public Point computeSize(final int wHint, final int hHint, final boolean changed) {
 		checkWidget();
 		final Point computedSize = this.buttonRenderer.computeSize(this, wHint, hHint, changed);

 		if (wHint != SWT.DEFAULT) {
 			computedSize.x = wHint;
 		}
 		if (hHint != SWT.DEFAULT) {
 			computedSize.y = hHint;
 		}
 		setWidth(computedSize.x);
 		setHeight(computedSize.y);
 		return computedSize;
 	}

 	/**
 	 * Returns a value which describes the position of the text or image in the receiver. The value will be one of <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code> unless the receiver is an <code>ARROW</code> button, in which case, the
 	 * alignment will indicate the direction of the arrow (one of <code>LEFT</code>, <code>RIGHT</code>, <code>UP</code> or <code>DOWN</code>).
 	 *
 	 * @return the alignment
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public int getAlignment() {
 		checkWidget();
 		return this.alignment;
 	}

 	/**
 	 * Gets the button renderer.
 	 *
 	 * @return the associated button renderer
 	 */
 	public ButtonRenderer getButtonRenderer() {
 		checkWidget();
 		return this.buttonRenderer;
 	}

 	/**
 	 * Returns the whole height of the widget.
 	 *
 	 * @return the receiver's height
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public int getHeight() {
 		checkWidget();
 		if (this.height == -1) {
 			return this.computeSize(SWT.DEFAULT, SWT.DEFAULT, false).y;
 		}
 		return this.height;
 	}

 	/**
 	 * Returns the receiver's image if it has one, or null if it does not.
 	 *
 	 * @return the receiver's image
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public Image getImage() {
 		checkWidget();
 		return this.image;
 	}

 	/**
 	 * Returns <code>true</code> if the receiver is selected, and false otherwise.
 	 *
 	 * @return the selection state
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public boolean getSelection() {
 		checkWidget();
 		return this.selected;
 	}

 	/**
 	 * Returns the receiver's text, which will be an empty string if it has never been set or if the receiver is an <code>ARROW</code> button.
 	 *
 	 * @return the receiver's text
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public String getText() {
 		checkWidget();
 		return this.text;
 	}

 	/**
 	 * Returns the whole width of the widget.
 	 *
 	 * @return the receiver's height
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public int getWidth() {
 		checkWidget();
 		if (this.width == -1) {
 			return computeSize(SWT.DEFAULT, SWT.DEFAULT, false).x;
 		}
 		return this.width;
 	}

 	/**
 	 * Removes the listener from the collection of listeners who will be
 	 * notified when the control is selected by the user.
 	 *
 	 * @param listener the listener which should no longer be notified
 	 * @see SelectionListener
 	 * @see #addSelectionListener
 	 * @exception IllegalArgumentException <ul>
 	 *                <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
 	 *                </ul>
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been
 	 *                disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
 	 *                thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void removeSelectionListener(final SelectionListener listener) {
 		checkWidget();
 		if (listener == null) {
 			SWT.error(SWT.ERROR_NULL_ARGUMENT);
 		}
 		this.selectionListeners.remove(listener);
 	}

 	/**
 	 * Controls how text, images and arrows will be displayed in the receiver. The argument should be one of <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code> unless the receiver is an <code>ARROW</code> button, in which case, the argument
 	 * indicates the direction of the arrow (one of <code>LEFT</code>, <code>RIGHT</code>, <code>UP</code> or <code>DOWN</code>).
 	 *
 	 * @param alignment the new alignment
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void setAlignment(final int alignment) {
 		checkWidget();
 		if (alignment != SWT.LEFT && alignment != SWT.RIGHT && alignment != SWT.CENTER) {
 			SWT.error(SWT.ERROR_INVALID_ARGUMENT);
 		}
 		this.alignment = alignment;
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the button renderer.
 	 *
 	 * @param buttonRenderer the button renderer to set
 	 */
 	public void setButtonRenderer(final ButtonRenderer buttonRenderer) {
 		this.buttonRenderer = buttonRenderer;
 	}

 	/**
 	 * Sets the height of the receiver.
 	 * <p>
 	 * Note: Attempting to set the width or height of the receiver to a negative number will cause that value to be set to zero instead.
 	 * </p>
 	 *
 	 * @param height the new width
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void setHeight(final int height) {
 		checkWidget();
 		this.height = Math.max(height, 0);
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the receiver's image to the argument, which may be <code>null</code> indicating that no image should be displayed.
 	 *
 	 * @param image the image to display on the receiver (may be <code>null</code>)
 	 *
 	 * @exception IllegalArgumentException <ul>
 	 *                <li>ERROR_INVALID_ARGUMENT - if the image has been disposed</li>
 	 *                </ul>
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void setImage(final Image image) {
 		checkWidget();
 		if (image != null && image.isDisposed()) {
 			SWT.error(SWT.ERROR_INVALID_ARGUMENT);
 		}
 		this.image = image;
 		this.buttonRenderer.createDisabledImage();
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the selection state of the receiver, if it is of type <code>TOGGLE</code>.
 	 *
 	 * @param selected the new selection state
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void setSelection(final boolean selected) {
 		checkWidget();
 		this.selected = selected;
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the receiver's text.
 	 *
 	 * @param string the new text
 	 *
 	 * @exception IllegalArgumentException <ul>
 	 *                <li>ERROR_NULL_ARGUMENT - if the text is null</li>
 	 *                </ul>
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void setText(final String string) {
 		checkWidget();
 		this.text = string;
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the width of the receiver.
 	 * <p>
 	 * Note: Attempting to set the width or height of the receiver to a negative number will cause that value to be set to zero instead.
 	 * </p>
 	 *
 	 * @param width the new width
 	 *
 	 * @exception SWTException <ul>
 	 *                <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
 	 *                <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
 	 *                </ul>
 	 */
 	public void setWidth(final int width) {
 		checkWidget();
 		this.width = Math.max(0, width);
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the enabled.
 	 *
 	 * @param enabled the new enabled
 	 * @see org.eclipse.swt.widgets.Control#setEnabled(boolean)
 	 */
 	@Override
 	public void setEnabled(final boolean enabled) {
 		super.setEnabled(enabled);
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the size.
 	 *
 	 * @param width the width
 	 * @param height the height
 	 * @see org.eclipse.swt.widgets.Control#setSize(int, int)
 	 */
 	@Override
 	public void setSize(final int width, final int height) {
 		super.setSize(width, height);
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the size.
 	 *
 	 * @param size the new size
 	 * @see org.eclipse.swt.widgets.Control#setSize(org.eclipse.swt.graphics.Point)
 	 */
 	@Override
 	public void setSize(final Point size) {
 		super.setSize(size);
 		redraw();
 		update();
 	}

 	/**
 	 * Sets the visible.
 	 *
 	 * @param visible the new visible
 	 * @see org.eclipse.swt.widgets.Control#setVisible(boolean)
 	 */
 	@Override
 	public void setVisible(final boolean visible) {
 		super.setVisible(visible);
 		redraw();
 		update();
 	}

 }
	/*******************************************************************************
	* Copyright (c) 2012 Laurent CARON
	* All rights reserved. This program and the accompanying materials
	* are made available under the terms of the Eclipse Public License v1.0
	* which accompanies this distribution, and is available at
	* http://www.eclipse.org/legal/epl-v10.html
	*
	* Contributors:
	* Laurent CARON (laurent.caron at gmail dot com) - initial API and implementation
	*******************************************************************************/
	package org.mihalis.opal.obutton;

	import java.util.ArrayList;
	import java.util.List;

	import org.eclipse.swt.SWT;
	import org.eclipse.swt.SWTException;
	import org.eclipse.swt.events.SelectionEvent;
	import org.eclipse.swt.events.SelectionListener;
	import org.eclipse.swt.graphics.Image;
	import org.eclipse.swt.graphics.Point;
	import org.eclipse.swt.widgets.Canvas;
	import org.eclipse.swt.widgets.Composite;
	import org.eclipse.swt.widgets.Event;
	import org.eclipse.swt.widgets.Listener;
	import org.eclipse.swt.widgets.Widget;

	/**
	* Instances of this class represent a selectable user interface object that issues notification when pressed and released.
	* <dl>
	* <dt><b>Styles:</b></dt>
	* <dd>ARROW, PUSH, TOGGLE</dd>
	* <dd>UP, DOWN, LEFT, RIGHT, CENTER</dd>
	* <dt><b>Events:</b></dt>
	* <dd>Selection</dd>
	* </dl>
	* <p>
	* Note: Only one of the styles ARROW, PUSH and TOGGLE may be specified.
	* </p>
	* <p>
	* Note: Only one of the styles LEFT, RIGHT, and CENTER may be specified.
	* </p>
	* <p>
	* Note: Only one of the styles UP, DOWN, LEFT, and RIGHT may be specified when the ARROW style is specified.
	* </p>
	*/
	public class OButton extends Canvas {

	/** The Constant IS_BUTTON_PRESSED. */
	private static final String IS_BUTTON_PRESSED = OButton.class.toString() + "_pressed";

	/** The selection listeners. */
	private final List<SelectionListener> selectionListeners;

	/** The alignment. */
	int alignment = SWT.LEFT;

	/** The button renderer. */
	private ButtonRenderer buttonRenderer;

	/** The selected. */
	boolean selected;

	/** The hover. */
	boolean hover;

	/** The text. */
	String text;

	/** The image. */
	Image image;

	/** The width. */
	private int width;

	/** The height. */
	private int height;

	/** The clicked. */
	private boolean clicked;

	/**
	* Constructs a new instance of this class given its parent and a style
	* value describing its behavior and appearance.
	* <p>
	* The style value is either one of the style constants defined in class
	* <code>SWT</code> which is applicable to instances of this class, or must
	* be built by <em>bitwise OR</em>'ing together (that is, using the
	* <code>int</code> "\|" operator) two or more of those <code>SWT</code>
	* style constants. The class description lists the style constants that are
	* applicable to the class. Style bits are also inherited from superclasses.
	* </p>
	*
	* @param parent a composite control which will be the parent of the new
	* instance (cannot be null)
	* @param style the style of control to construct
	* @see SWT#ARROW
	* @see SWT#CHECK
	* @see SWT#PUSH
	* @see SWT#RADIO
	* @see SWT#TOGGLE
	* @see SWT#FLAT
	* @see SWT#UP
	* @see SWT#DOWN
	* @see SWT#LEFT
	* @see SWT#RIGHT
	* @see SWT#CENTER
	* @see Widget#checkSubclass
	* @see Widget#getStyle
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the parent</li>
	* <li>ERROR_INVALID_SUBCLASS - if this class is not an
	* allowed subclass</li>
	* </ul>
	*/
	public OButton(final Composite parent, final int style) {
	super(parent, checkStyle(style) \| SWT.DOUBLE_BUFFERED);
	this.selectionListeners = new ArrayList<SelectionListener>();
	this.buttonRenderer = DefaultButtonRenderer.getInstance();
	this.width = this.height = -1;
	addListeners();
	}

	/**
	* Check style.
	*
	* @param style the style
	* @return the int
	*/
	private static int checkStyle(int style) {
	style = checkBits(style, SWT.PUSH, SWT.ARROW, SWT.TOGGLE, 0);
	if ((style & (SWT.PUSH \| SWT.TOGGLE)) != 0) {
	return checkBits(style, SWT.CENTER, SWT.LEFT, SWT.RIGHT, 0);
	}
	if ((style & SWT.ARROW) != 0) {
	return checkBits(style, SWT.UP, SWT.DOWN, SWT.LEFT, SWT.RIGHT);
	}
	return style;
	}

	/**
	* Check bits.
	*
	* @param style the style
	* @param int0 the int0
	* @param int1 the int1
	* @param int2 the int2
	* @param int3 the int3
	* @return the int
	*/
	private static int checkBits(int style, final int int0, final int int1, final int int2, final int int3) {
	final int mask = int0 \| int1 \| int2 \| int3;
	if ((style & mask) == 0) {
	style \|= int0;
	}
	if ((style & int0) != 0) {
	style = style & ~mask \| int0;
	}
	if ((style & int1) != 0) {
	style = style & ~mask \| int1;
	}
	if ((style & int2) != 0) {
	style = style & ~mask \| int2;
	}
	if ((style & int3) != 0) {
	style = style & ~mask \| int3;
	}
	return style;
	}

	/**
	* Adds the listeners.
	*/
	private void addListeners() {
	final Listener listener = new Listener() {

	@Override
	public void handleEvent(final Event event) {
	switch (event.type) {
	case SWT.MouseEnter:
	OButton.this.hover = true;
	redraw();
	update();
	break;
	case SWT.MouseExit:
	OButton.this.hover = false;
	redraw();
	update();
	break;
	case SWT.MouseDown:
	OButton.this.clicked = true;
	OButton.this.setData(IS_BUTTON_PRESSED, "*");
	redraw();
	update();
	break;
	case SWT.MouseUp:
	if (OButton.this.getData(IS_BUTTON_PRESSED) == null) {
	return;
	}
	OButton.this.setData(IS_BUTTON_PRESSED, null);
	OButton.this.clicked = false;
	OButton.this.selected = !OButton.this.selected;
	redraw();
	update();
	fireSelectionEvent();
	break;
	case SWT.Paint:
	handlePaintEvent(event);
	break;
	case SWT.KeyDown:
	if (event.keyCode == SWT.TAB) {
	if (event.stateMask == SWT.SHIFT) {
	OButton.this.traverse(SWT.TRAVERSE_TAB_PREVIOUS);
	} else {
	OButton.this.traverse(SWT.TRAVERSE_TAB_NEXT);
	}
	}
	break;
	case SWT.Dispose:
	OButton.this.buttonRenderer.dispose();
	break;

	}

	}
	};

	final int[] events = new int[] { SWT.MouseEnter, SWT.MouseExit, SWT.MouseDown, SWT.MouseUp, SWT.Paint, SWT.Dispose };
	for (final int event : events) {
	addListener(event, listener);
	}
	}

	/**
	* Fire selection event.
	*/
	protected void fireSelectionEvent() {
	final Event event = new Event();
	event.widget = this;
	event.display = getDisplay();
	event.type = SWT.Selection;
	for (final SelectionListener selectionListener : this.selectionListeners) {
	selectionListener.widgetSelected(new SelectionEvent(event));
	}
	}

	/**
	* Handle paint event.
	*
	* @param event the event
	*/
	private void handlePaintEvent(final Event event) {
	if (!isEnabled()) {
	this.buttonRenderer.drawButtonWhenDisabled(event.gc, this);
	return;
	}

	if (this.clicked) {
	this.buttonRenderer.drawButtonWhenClicked(event.gc, this);
	return;
	}

	if (this.hover) {
	this.buttonRenderer.drawButtonWhenMouseHover(event.gc, this);
	return;
	}

	final boolean isToggleButton = (getStyle() & SWT.TOGGLE) == SWT.TOGGLE;
	if (isToggleButton && this.selected) {
	this.buttonRenderer.drawButtonWhenSelected(event.gc, this);
	return;
	}

	this.buttonRenderer.drawButton(event.gc, this);
	}

	/**
	* Adds the listener to the collection of listeners who will be notified
	* when the control is selected by the user, by sending it one of the
	* messages defined in the <code>SelectionListener</code> interface.
	* <p>
	* <code>widgetSelected</code> is called when the control is selected by the
	* user. <code>widgetDefaultSelected</code> is not called.
	* </p>
	*
	* @param listener the listener which should be notified
	* @see SelectionListener
	* @see #removeSelectionListener
	* @see SelectionEvent
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been
	* disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public void addSelectionListener(final SelectionListener listener) {
	checkWidget();
	if (listener == null) {
	SWT.error(SWT.ERROR_NULL_ARGUMENT);
	}
	this.selectionListeners.add(listener);
	}

	/**
	* Compute size.
	*
	* @param wHint the w hint
	* @param hHint the h hint
	* @param changed the changed
	* @return the point
	* @see org.eclipse.swt.widgets.Composite#computeSize(int, int, boolean)
	*/
	@Override
	public Point computeSize(final int wHint, final int hHint, final boolean changed) {
	checkWidget();
	final Point computedSize = this.buttonRenderer.computeSize(this, wHint, hHint, changed);

	if (wHint != SWT.DEFAULT) {
	computedSize.x = wHint;
	}
	if (hHint != SWT.DEFAULT) {
	computedSize.y = hHint;
	}
	setWidth(computedSize.x);
	setHeight(computedSize.y);
	return computedSize;
	}

	/**
	* Returns a value which describes the position of the text or image in the receiver. The value will be one of <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code> unless the receiver is an <code>ARROW</code> button, in which case, the
	* alignment will indicate the direction of the arrow (one of <code>LEFT</code>, <code>RIGHT</code>, <code>UP</code> or <code>DOWN</code>).
	*
	* @return the alignment
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public int getAlignment() {
	checkWidget();
	return this.alignment;
	}

	/**
	* Gets the button renderer.
	*
	* @return the associated button renderer
	*/
	public ButtonRenderer getButtonRenderer() {
	checkWidget();
	return this.buttonRenderer;
	}

	/**
	* Returns the whole height of the widget.
	*
	* @return the receiver's height
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public int getHeight() {
	checkWidget();
	if (this.height == -1) {
	return this.computeSize(SWT.DEFAULT, SWT.DEFAULT, false).y;
	}
	return this.height;
	}

	/**
	* Returns the receiver's image if it has one, or null if it does not.
	*
	* @return the receiver's image
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public Image getImage() {
	checkWidget();
	return this.image;
	}

	/**
	* Returns <code>true</code> if the receiver is selected, and false otherwise.
	*
	* @return the selection state
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public boolean getSelection() {
	checkWidget();
	return this.selected;
	}

	/**
	* Returns the receiver's text, which will be an empty string if it has never been set or if the receiver is an <code>ARROW</code> button.
	*
	* @return the receiver's text
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public String getText() {
	checkWidget();
	return this.text;
	}

	/**
	* Returns the whole width of the widget.
	*
	* @return the receiver's height
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public int getWidth() {
	checkWidget();
	if (this.width == -1) {
	return computeSize(SWT.DEFAULT, SWT.DEFAULT, false).x;
	}
	return this.width;
	}

	/**
	* Removes the listener from the collection of listeners who will be
	* notified when the control is selected by the user.
	*
	* @param listener the listener which should no longer be notified
	* @see SelectionListener
	* @see #addSelectionListener
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the listener is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been
	* disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the
	* thread that created the receiver</li>
	* </ul>
	*/
	public void removeSelectionListener(final SelectionListener listener) {
	checkWidget();
	if (listener == null) {
	SWT.error(SWT.ERROR_NULL_ARGUMENT);
	}
	this.selectionListeners.remove(listener);
	}

	/**
	* Controls how text, images and arrows will be displayed in the receiver. The argument should be one of <code>LEFT</code>, <code>RIGHT</code> or <code>CENTER</code> unless the receiver is an <code>ARROW</code> button, in which case, the argument
	* indicates the direction of the arrow (one of <code>LEFT</code>, <code>RIGHT</code>, <code>UP</code> or <code>DOWN</code>).
	*
	* @param alignment the new alignment
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setAlignment(final int alignment) {
	checkWidget();
	if (alignment != SWT.LEFT && alignment != SWT.RIGHT && alignment != SWT.CENTER) {
	SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	}
	this.alignment = alignment;
	redraw();
	update();
	}

	/**
	* Sets the button renderer.
	*
	* @param buttonRenderer the button renderer to set
	*/
	public void setButtonRenderer(final ButtonRenderer buttonRenderer) {
	this.buttonRenderer = buttonRenderer;
	}

	/**
	* Sets the height of the receiver.
	* <p>
	* Note: Attempting to set the width or height of the receiver to a negative number will cause that value to be set to zero instead.
	* </p>
	*
	* @param height the new width
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setHeight(final int height) {
	checkWidget();
	this.height = Math.max(height, 0);
	redraw();
	update();
	}

	/**
	* Sets the receiver's image to the argument, which may be <code>null</code> indicating that no image should be displayed.
	*
	* @param image the image to display on the receiver (may be <code>null</code>)
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_INVALID_ARGUMENT - if the image has been disposed</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setImage(final Image image) {
	checkWidget();
	if (image != null && image.isDisposed()) {
	SWT.error(SWT.ERROR_INVALID_ARGUMENT);
	}
	this.image = image;
	this.buttonRenderer.createDisabledImage();
	redraw();
	update();
	}

	/**
	* Sets the selection state of the receiver, if it is of type <code>TOGGLE</code>.
	*
	* @param selected the new selection state
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setSelection(final boolean selected) {
	checkWidget();
	this.selected = selected;
	redraw();
	update();
	}

	/**
	* Sets the receiver's text.
	*
	* @param string the new text
	*
	* @exception IllegalArgumentException <ul>
	* <li>ERROR_NULL_ARGUMENT - if the text is null</li>
	* </ul>
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setText(final String string) {
	checkWidget();
	this.text = string;
	redraw();
	update();
	}

	/**
	* Sets the width of the receiver.
	* <p>
	* Note: Attempting to set the width or height of the receiver to a negative number will cause that value to be set to zero instead.
	* </p>
	*
	* @param width the new width
	*
	* @exception SWTException <ul>
	* <li>ERROR_WIDGET_DISPOSED - if the receiver has been disposed</li>
	* <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the receiver</li>
	* </ul>
	*/
	public void setWidth(final int width) {
	checkWidget();
	this.width = Math.max(0, width);
	redraw();
	update();
	}

	/**
	* Sets the enabled.
	*
	* @param enabled the new enabled
	* @see org.eclipse.swt.widgets.Control#setEnabled(boolean)
	*/
	@Override
	public void setEnabled(final boolean enabled) {
	super.setEnabled(enabled);
	redraw();
	update();
	}

	/**
	* Sets the size.
	*
	* @param width the width
	* @param height the height
	* @see org.eclipse.swt.widgets.Control#setSize(int, int)
	*/
	@Override
	public void setSize(final int width, final int height) {
	super.setSize(width, height);
	redraw();
	update();
	}

	/**
	* Sets the size.
	*
	* @param size the new size
	* @see org.eclipse.swt.widgets.Control#setSize(org.eclipse.swt.graphics.Point)
	*/
	@Override
	public void setSize(final Point size) {
	super.setSize(size);
	redraw();
	update();
	}

	/**
	* Sets the visible.
	*
	* @param visible the new visible
	* @see org.eclipse.swt.widgets.Control#setVisible(boolean)
	*/
	@Override
	public void setVisible(final boolean visible) {
	super.setVisible(visible);
	redraw();
	update();
	}

	}