bundles/org.eclipse.swt/Eclipse SWT/carbon/org/eclipse/swt/widgets/Link.java

/*******************************************************************************
 * Copyright (c) 2000, 2008 IBM Corporation and others.
 * 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:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;

import org.eclipse.swt.internal.carbon.CFRange;
import org.eclipse.swt.internal.carbon.OS;
import org.eclipse.swt.internal.carbon.Rect;
import org.eclipse.swt.internal.carbon.CGPoint;

import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;

/**
 * Instances of this class represent a selectable
 * user interface object that displays a text with 
 * links.
 * <p>
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>(none)</dd>
 * <dt><b>Events:</b></dt>
 * <dd>Selection</dd>
 * </dl>
 * <p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see <a href="http://www.eclipse.org/swt/snippets/#link">Link snippets</a>
 * @see <a href="http://www.eclipse.org/swt/examples.php">SWT Example: ControlExample</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 * 
 * @since 3.1
 * @noextend This class is not intended to be subclassed by clients.
 */
public class Link extends Control {
	String text;
	TextLayout layout;
	Color linkColor, disabledColor;
	Point [] offsets;
	Point selection;
	String [] ids;
	int [] mnemonics;
	int focusIndex;
	
	static final RGB LINK_FOREGROUND = new RGB (0, 51, 153);
	static final RGB LINK_DISABLED_FOREGROUND = new RGB (172, 168, 153);
	static final String [] AX_ATTRIBUTES = {
		OS.kAXTitleAttribute,
	};

/**
 * 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
 *
 * @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>
 *
 * @see Widget#checkSubclass
 * @see Widget#getStyle
 */
public Link (Composite parent, int style) {
	super (parent, style);
}

/**
 * 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
 *
 * @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>
 *
 * @see SelectionListener
 * @see #removeSelectionListener
 * @see SelectionEvent
 */
public void addSelectionListener (SelectionListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	TypedListener typedListener = new TypedListener (listener);
	addListener (SWT.Selection, typedListener);
	addListener (SWT.DefaultSelection, typedListener);
}

int callFocusEventHandler (int nextHandler, int theEvent) {
	return OS.noErr;
}

public Point computeSize (int wHint, int hHint, boolean changed) {
	checkWidget ();
	if (wHint != SWT.DEFAULT && wHint < 0) wHint = 0;
	if (hHint != SWT.DEFAULT && hHint < 0) hHint = 0;
	int width, height;
	int layoutWidth = layout.getWidth ();
	//TEMPORARY CODE
	if (wHint == 0) {
		layout.setWidth (1);
		Rectangle rect = layout.getBounds ();
		width = 0;
		height = rect.height;
	} else {
		layout.setWidth (wHint);
		Rectangle rect = layout.getBounds ();
		width = rect.width;
		height = rect.height;
	}
	layout.setWidth (layoutWidth);		
	if (wHint != SWT.DEFAULT) width = wHint;
	if (hHint != SWT.DEFAULT) height = hHint;
	int border = getBorderWidth ();
	width += border * 2;
	height += border * 2;
	return new Point (width, height);
}

void createHandle () {
	state |= GRAB | THEME_BACKGROUND;
	int features = OS.kControlSupportsFocus;
	int [] outControl = new int [1];
	int window = OS.GetControlOwner (parent.handle);
	OS.CreateUserPaneControl (window, null, features, outControl);
	if (outControl [0] == 0) error (SWT.ERROR_NO_HANDLES);
	handle = outControl [0];
	layout = new TextLayout (display);
	linkColor = new Color (display, LINK_FOREGROUND);
	disabledColor = new Color (display, LINK_DISABLED_FOREGROUND);
	offsets = new Point [0];
	ids = new String [0];
	mnemonics = new int [0]; 
	selection = new Point (-1, -1);
	focusIndex = -1;
}

void createWidget () {
	super.createWidget ();
	layout.setFont (getFont ());
	text = "";
}

void drawBackground (int control, int context) {
	fillBackground (control, context, null);
	if (!hasFocus () || !drawFocusRing () || focusIndex == -1) return;
	int [] outMetric = new int [1];
	OS.GetThemeMetric (OS.kThemeMetricFocusRectOutset, outMetric);
	outMetric[0]--;
	Rect r = new Rect ();
	Rectangle [] rects = getRectangles (focusIndex);
	for (int i = 0; i < rects.length; i++) {
		Rectangle rect = rects [i];
		r.left = (short) (rect.x + outMetric[0]);
		r.top = (short) (rect.y + outMetric[0]);
		r.right = (short) (r.left + rect.width - (outMetric[0] * 2));
		r.bottom = (short) (r.top + rect.height - (outMetric[0] * 2));
		OS.DrawThemeFocusRect (r, true);
	}
}

void drawWidget (int control, int context, int damageRgn, int visibleRgn, int theEvent) {
	GCData data = new GCData ();
	data.paintEvent = theEvent;
	data.visibleRgn = visibleRgn;
	GC gc = GC.carbon_new (this, data);
	int selStart = selection.x;
	int selEnd = selection.y;
	if (selStart > selEnd) {
		selStart = selection.y;
		selEnd = selection.x;
	}
	// temporary code to disable text selection
	selStart = selEnd = -1;
	if ((state & DISABLED) != 0) gc.setForeground (disabledColor);
	layout.draw (gc, 0, 0, selStart, selEnd, null, null);
	gc.dispose ();
	super.drawWidget (control, context, damageRgn, visibleRgn, theEvent);
}

void enableWidget (boolean enabled) {
	super.enableWidget (enabled);
	TextStyle linkStyle = new TextStyle (null, enabled ? linkColor : disabledColor, null);
	linkStyle.underline = true;
	for (int i = 0; i < offsets.length; i++) {
		Point point = offsets [i];
		layout.setStyle (linkStyle, point.x, point.y);
	}
	redraw ();
}

String [] getAxAttributes () {
	return AX_ATTRIBUTES;
}

String getNameText () {
	return getText ();
}

Rectangle [] getRectangles (int linkIndex) {
	int lineCount = layout.getLineCount ();
	Rectangle [] rects = new Rectangle [lineCount];
	int [] lineOffsets = layout.getLineOffsets ();
	Point point = offsets [linkIndex];
	int lineStart = 1;
	while (point.x > lineOffsets [lineStart]) lineStart++;
	int lineEnd = 1;
	while (point.y > lineOffsets [lineEnd]) lineEnd++;
	int index = 0;
	if (lineStart == lineEnd) {
		rects [index++] = layout.getBounds (point.x, point.y);		
	} else {
		rects [index++] = layout.getBounds (point.x, lineOffsets [lineStart]-1);
		rects [index++] = layout.getBounds (lineOffsets [lineEnd-1], point.y);
		if (lineEnd - lineStart > 1) {
			for (int i = lineStart; i < lineEnd - 1; i++) {
				rects [index++] = layout.getLineBounds (i);
			}
		}
	}
	if (rects.length != index) {
		Rectangle [] tmp = new Rectangle [index];
		System.arraycopy (rects, 0, tmp, 0, index);
		rects = tmp;
	}	
	return rects;
}

/**
 * Returns the receiver's text, which will be an empty
 * string if it has never been set.
 *
 * @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 text;
}

int kEventAccessibleGetNamedAttribute (int nextHandler, int theEvent, int userData) {
	int code = OS.eventNotHandledErr;
	int [] stringRef = new int [1];
	OS.GetEventParameter (theEvent, OS.kEventParamAccessibleAttributeName, OS.typeCFStringRef, null, 4, null, stringRef);
	int length = 0;
	if (stringRef [0] != 0) length = OS.CFStringGetLength (stringRef [0]);
	char [] buffer = new char [length];
	CFRange range = new CFRange ();
	range.length = length;
	OS.CFStringGetCharacters (stringRef [0], range, buffer);
	String attributeName = new String(buffer);
	if (attributeName.equals (OS.kAXRoleAttribute) || attributeName.equals (OS.kAXRoleDescriptionAttribute)) {
		String roleText = OS.kAXLinkRole;
		buffer = new char [roleText.length ()];
		roleText.getChars (0, buffer.length, buffer, 0);
		stringRef [0] = OS.CFStringCreateWithCharacters (OS.kCFAllocatorDefault, buffer, buffer.length);
		if (stringRef [0] != 0) {
			if (attributeName.equals (OS.kAXRoleAttribute)) {
				OS.SetEventParameter (theEvent, OS.kEventParamAccessibleAttributeValue, OS.typeCFStringRef, 4, stringRef);
			} else { // kAXRoleDescriptionAttribute
				int stringRef2 = OS.HICopyAccessibilityRoleDescription (stringRef [0], 0);
				OS.SetEventParameter (theEvent, OS.kEventParamAccessibleAttributeValue, OS.typeCFStringRef, 4, new int [] {stringRef2});
				OS.CFRelease(stringRef2);
			}
			OS.CFRelease(stringRef [0]);
			code = OS.noErr;
		}
	} else if (attributeName.equals (OS.kAXTitleAttribute) || attributeName.equals (OS.kAXDescriptionAttribute)) {
		String text = parse (getText ());
		if (text != null) {
			buffer = new char [text.length ()];
			text.getChars (0, buffer.length, buffer, 0);
			stringRef [0] = OS.CFStringCreateWithCharacters (OS.kCFAllocatorDefault, buffer, buffer.length);
			if (stringRef [0] != 0) {
				OS.SetEventParameter (theEvent, OS.kEventParamAccessibleAttributeValue, OS.typeCFStringRef, 4, stringRef);
				OS.CFRelease(stringRef [0]);
				code = OS.noErr;
			}
		}
	}
	if (accessible != null) {
		code = accessible.internal_kEventAccessibleGetNamedAttribute (nextHandler, theEvent, code);
	}
	return code;
}

int kEventControlGetFocusPart (int nextHandler, int theEvent, int userData) {
	return OS.noErr;
}

int kEventControlSetFocusPart (int nextHandler, int theEvent, int userData) {
	int result = super.kEventControlSetFocusPart (nextHandler, theEvent, userData);
	if (result == OS.noErr) redraw ();
	return result;
}

int kEventMouseMoved (int nextHandler, int theEvent, int userData) {
	int result = super.kEventMouseMoved (nextHandler, theEvent, userData);
	if (result == OS.noErr) return result;
	CGPoint pt = new CGPoint ();
	OS.GetEventParameter (theEvent, OS.kEventParamWindowMouseLocation, OS.typeHIPoint, null, CGPoint.sizeof, null, pt);
	OS.HIViewConvertPoint (pt, 0, handle);
	int x = (int) pt.x;
	int y = (int) pt.y;
	for (int j = 0; j < offsets.length; j++) {
		Rectangle [] rects = getRectangles (j);
		for (int i = 0; i < rects.length; i++) {
			Rectangle rectangle = rects [i];
			if (rectangle.contains (x, y)) {
				setCursor (display.getSystemCursor (SWT.CURSOR_HAND));
				return result;
			}
		}
	}
	setCursor (null);
	return result;
}

int kEventUnicodeKeyPressed (int nextHandler, int theEvent, int userData) {
	int result = super.kEventUnicodeKeyPressed (nextHandler, theEvent, userData);
	if (result == OS.noErr) return result;
	if (focusIndex == -1) return result;
	int [] keyboardEvent = new int [1];
	OS.GetEventParameter (theEvent, OS.kEventParamTextInputSendKeyboardEvent, OS.typeEventRef, null, keyboardEvent.length * 4, null, keyboardEvent);
	int [] keyCode = new int [1];
	OS.GetEventParameter (keyboardEvent [0], OS.kEventParamKeyCode, OS.typeUInt32, null, keyCode.length * 4, null, keyCode);
	switch (keyCode [0]) {
		case 36: /* Return */
		case 49: /* Space */
		case 76: /* Enter */
			Event event = new Event ();
			event.text = ids [focusIndex];
			sendEvent (SWT.Selection, event);
			break;
		case 48: /* Tab */
			int [] modifiers = new int [1];
			OS.GetEventParameter (keyboardEvent [0], OS.kEventParamKeyModifiers, OS.typeUInt32, null, 4, null, modifiers);
			boolean next = (modifiers [0] & OS.shiftKey) == 0;
			if (next) {
				if (focusIndex < offsets.length - 1) {
					focusIndex++;
					redraw ();
				}
			} else {
				if (focusIndex > 0) {
					focusIndex--;
					redraw ();
				} 
			}
			break;
			
	}
	return result;
}

void releaseWidget () {
	super.releaseWidget ();
	if (layout != null) layout.dispose ();
	layout = null;
	if (linkColor != null) linkColor.dispose ();
	linkColor = null;
	if (disabledColor != null) disabledColor.dispose ();
	disabledColor = null;
	offsets = null;
	ids = null;
	mnemonics = null;
	text = null;
}

/**
 * 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
 *
 * @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>
 *
 * @see SelectionListener
 * @see #addSelectionListener
 */
public void removeSelectionListener (SelectionListener listener) {
	checkWidget ();
	if (listener == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (eventTable == null) return;
	eventTable.unhook (SWT.Selection, listener);
	eventTable.unhook (SWT.DefaultSelection, listener);	
}

String parse (String string) {
	int length = string.length ();
	offsets = new Point [length / 4];
	ids = new String [length / 4];
	mnemonics = new int [length / 4 + 1];
	StringBuffer result = new StringBuffer ();
	char [] buffer = new char [length];
	string.getChars (0, string.length (), buffer, 0);
	int index = 0, state = 0, linkIndex = 0;
	int start = 0, tagStart = 0, linkStart = 0, endtagStart = 0, refStart = 0;
	while (index < length) {
		char c = Character.toLowerCase (buffer [index]);
		switch (state) {
			case 0: 
				if (c == '<') {
					tagStart = index;
					state++;
				}
				break;
			case 1:
				if (c == 'a') state++;
				break;
			case 2:
				switch (c) {
					case 'h':
						state = 7;
						break;
					case '>':
						linkStart = index  + 1;
						state++;
						break;
					default:
						if (Character.isWhitespace(c)) break;
						else state = 13;
				}
				break;
			case 3:
				if (c == '<') {
					endtagStart = index;
					state++;
				}
				break;
			case 4:
				state = c == '/' ? state + 1 : 3;
				break;
			case 5:
				state = c == 'a' ? state + 1 : 3;
				break;
			case 6:
				if (c == '>') {
					mnemonics [linkIndex] = parseMnemonics (buffer, start, tagStart, result);
					int offset = result.length ();
					parseMnemonics (buffer, linkStart, endtagStart, result);
					offsets [linkIndex] = new Point (offset, result.length () - 1);
					if (ids [linkIndex] == null) {
						ids [linkIndex] = new String (buffer, linkStart, endtagStart - linkStart);
					}
					linkIndex++;
					start = tagStart = linkStart = endtagStart = refStart = index + 1;
					state = 0;
				} else {
					state = 3;
				}
				break;
			case 7:
				state = c == 'r' ? state + 1 : 0;
				break;
			case 8:
				state = c == 'e' ? state + 1 : 0;
				break;
			case 9:
				state = c == 'f' ? state + 1 : 0;
				break;
			case 10:
				state = c == '=' ? state + 1 : 0;
				break;
			case 11:
				if (c == '"') {
					state++;
					refStart = index + 1;
				} else {
					state = 0;
				}
				break;
			case 12:
				if (c == '"') {
					ids[linkIndex] = new String (buffer, refStart, index - refStart);
					state = 2;
				}
				break;
			case 13:
				if (Character.isWhitespace (c)) {
					state = 0;
				} else if (c == '='){
					state++;
				}
				break;
			case 14:
				state = c == '"' ? state + 1 : 0;
				break;
			case 15:
				if (c == '"') state = 2;
				break;
			default:
				state = 0;
				break;
		}
		index++;
	}
	if (start < length) {
		int tmp = parseMnemonics (buffer, start, tagStart, result);
		int mnemonic = parseMnemonics (buffer, Math.max (tagStart, linkStart), length, result);
		if (mnemonic == -1) mnemonic = tmp;
		mnemonics [linkIndex] = mnemonic;
	} else {
		mnemonics [linkIndex] = -1;
	}
	if (offsets.length != linkIndex) {
		Point [] newOffsets = new Point [linkIndex];
		System.arraycopy (offsets, 0, newOffsets, 0, linkIndex);
		offsets = newOffsets;
		String [] newIDs = new String [linkIndex];
		System.arraycopy (ids, 0, newIDs, 0, linkIndex);
		ids = newIDs;
		int [] newMnemonics = new int [linkIndex + 1];
		System.arraycopy (mnemonics, 0, newMnemonics, 0, linkIndex + 1);
		mnemonics = newMnemonics;		
	}
	return result.toString ();
}

int parseMnemonics (char[] buffer, int start, int end, StringBuffer result) {
	int mnemonic = -1, index = start;
	while (index < end) {
		if (buffer [index] == '&') {
			if (index + 1 < end && buffer [index + 1] == '&') {
				result.append (buffer [index]);
				index++;
			} else {
				mnemonic = result.length();
			}
		} else {
			result.append (buffer [index]);
		}
		index++;
	}
	return mnemonic;
}

boolean sendMouseEvent (int type, short button, int count, int detail, boolean send, int chord, short x, short y, int modifiers) {
	boolean result = super.sendMouseEvent (type, button, count, detail, send, chord, x, y, modifiers);
	switch (type) {
		case SWT.MouseDown:
			if (button == 1 && count == 1) {
				int offset = layout.getOffset (x, y, null);
				int oldSelectionX = selection.x;
				int oldSelectionY = selection.y;
				selection.x = offset;
				selection.y = -1;
				if (oldSelectionX != -1 && oldSelectionY != -1) {
					if (oldSelectionX > oldSelectionY) {
						int temp = oldSelectionX;
						oldSelectionX = oldSelectionY;
						oldSelectionY = temp;
					}
					Rectangle rectangle = layout.getBounds (oldSelectionX, oldSelectionY);
					redraw (rectangle.x, rectangle.y, rectangle.width, rectangle.height, false);
				}		
				for (int j = 0; j < offsets.length; j++) {
					Rectangle [] rects = getRectangles (j);
					for (int i = 0; i < rects.length; i++) {
						Rectangle rectangle = rects [i];
						if (rectangle.contains (x, y)) {
							focusIndex = j;
							redraw ();
							setFocus ();
							return result;
						}
					}
				}
			}
			break;
		case SWT.MouseMove:
			if ((chord & 0x01) != 0) {
				int oldSelection = selection.y;
				selection.y = layout.getOffset (x, y, null);
				if (selection.y != oldSelection) {
					int newSelection = selection.y;
					if (oldSelection > newSelection) {
						int temp = oldSelection;
						oldSelection = newSelection;
						newSelection = temp;
					}
					Rectangle rectangle = layout.getBounds (oldSelection, newSelection);
					redraw (rectangle.x, rectangle.y, rectangle.width, rectangle.height, false);
				}
			}
			break;
		case SWT.MouseUp:
			if (focusIndex == -1) break;
			if (button == 1) {
				Rectangle [] rects = getRectangles (focusIndex);
				for (int i = 0; i < rects.length; i++) {
					Rectangle rectangle = rects [i];
					if (rectangle.contains (x, y)) {
						Event event = new Event ();
						event.text = ids [focusIndex];
						notifyListeners (SWT.Selection, event);
						return result;
					}
				}
			}
			break;
	}
	
	return result;
}

int setBounds (int x, int y, int width, int height, boolean move, boolean resize, boolean events) {
	int result = super.setBounds(x, y, width, height, move, resize, events);
	if ((result & RESIZED) != 0) {
		layout.setWidth (width > 0 ? width : -1);
	}
	return result;
}

void setFontStyle (Font font) {
	super.setFontStyle (font);
	layout.setFont (getFont ());
}

/**
 * Sets the receiver's text.
 * <p>
 * The string can contain both regular text and hyperlinks.  A hyperlink
 * is delimited by an anchor tag, &lt;A&gt; and &lt;/A&gt;.  Within an
 * anchor, a single HREF attribute is supported.  When a hyperlink is
 * selected, the text field of the selection event contains either the
 * text of the hyperlink or the value of its HREF, if one was specified.
 * In the rare case of identical hyperlinks within the same string, the
 * HREF attribute can be used to distinguish between them.  The string may
 * include the mnemonic character and line delimiters. The only delimiter
 * the HREF attribute supports is the quotation mark (").
 * </p>
 * 
 * @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 (String string) {
	checkWidget ();
	if (string == null) error (SWT.ERROR_NULL_ARGUMENT);
	if (string.equals (text)) return;
	text = string;
	layout.setText (parse (string));
	focusIndex = offsets.length > 0 ? 0 : -1 ;
	selection.x = selection.y = -1;
	boolean enabled = (state & DISABLED) == 0;
	TextStyle linkStyle = new TextStyle (null, enabled ? linkColor : disabledColor, null);
	linkStyle.underline = true;
	for (int i = 0; i < offsets.length; i++) {
		Point point = offsets [i];
		layout.setStyle (linkStyle, point.x, point.y);
	}
	/*
	* This code is intentionally commented. Mnemonics are 
	* not drawn on the Macintosh.
	*/
//	TextStyle mnemonicStyle = new TextStyle (null, null, null);
//	mnemonicStyle.underline = true;
//	for (int i = 0; i < mnemonics.length; i++) {
//		int mnemonic  = mnemonics [i];
//		if (mnemonic != -1) {
//			layout.setStyle (mnemonicStyle, mnemonic, mnemonic);
//		}
//	}
	redraw ();    
}

int traversalCode (int key, int theEvent) {
	if (offsets.length == 0) return 0;
	int bits = super.traversalCode (key, theEvent);
	if (key == 48 /* Tab */ && theEvent != 0) {
		int [] modifiers = new int [1];
		OS.GetEventParameter (theEvent, OS.kEventParamKeyModifiers, OS.typeUInt32, null, 4, null, modifiers);
		boolean next = (modifiers [0] & OS.shiftKey) == 0;
		if (next && focusIndex < offsets.length - 1) {
			return bits & ~ SWT.TRAVERSE_TAB_NEXT;
		}
		if (!next && focusIndex > 0) {
			return bits & ~ SWT.TRAVERSE_TAB_PREVIOUS;
		}
	}
	return bits;
}

}