org.eclipse.swt.widgets.Tracker.java Source code

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/*******************************************************************************
 * Copyright (c) 2000, 2013 IBM Corporation and others.
 *
 * This program and the accompanying materials
 * are made available under the terms of the Eclipse Public License 2.0
 * which accompanies this distribution, and is available at
 * https://www.eclipse.org/legal/epl-2.0/
 *
 * SPDX-License-Identifier: EPL-2.0
 *
 * Contributors:
 *     IBM Corporation - initial API and implementation
 *******************************************************************************/
package org.eclipse.swt.widgets;

import org.eclipse.swt.*;
import org.eclipse.swt.events.*;
import org.eclipse.swt.graphics.*;
import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.win32.*;

/**
 *  Instances of this class implement rubber banding rectangles that are
 *  drawn onto a parent <code>Composite</code> or <code>Display</code>.
 *  These rectangles can be specified to respond to mouse and key events
 *  by either moving or resizing themselves accordingly.  Trackers are
 *  typically used to represent window geometries in a lightweight manner.
 *
 * <dl>
 * <dt><b>Styles:</b></dt>
 * <dd>LEFT, RIGHT, UP, DOWN, RESIZE</dd>
 * <dt><b>Events:</b></dt>
 * <dd>Move, Resize</dd>
 * </dl>
 * <p>
 * Note: Rectangle move behavior is assumed unless RESIZE is specified.
 * </p><p>
 * IMPORTANT: This class is <em>not</em> intended to be subclassed.
 * </p>
 *
 * @see <a href="http://www.eclipse.org/swt/snippets/#tracker">Tracker snippets</a>
 * @see <a href="http://www.eclipse.org/swt/">Sample code and further information</a>
 * @noextend This class is not intended to be subclassed by clients.
 */
public class Tracker extends Widget {
    Control parent;
    boolean tracking, cancelled, stippled;
    Rectangle[] rectangles = new Rectangle[0], proportions = rectangles;
    Rectangle bounds;
    long resizeCursor;
    Cursor clientCursor;
    int cursorOrientation = SWT.NONE;
    boolean inEvent = false;
    boolean drawn;
    long hwndTransparent, hwndOpaque, oldTransparentProc, oldOpaqueProc;
    int oldX, oldY;

    /*
    * The following values mirror step sizes on Windows
    */
    final static int STEPSIZE_SMALL = 1;
    final static int STEPSIZE_LARGE = 9;

    /**
     * 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 widget which will be the parent of the new instance (cannot be null)
     * @param style the style of widget 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 SWT#LEFT
     * @see SWT#RIGHT
     * @see SWT#UP
     * @see SWT#DOWN
     * @see SWT#RESIZE
     * @see Widget#checkSubclass
     * @see Widget#getStyle
     */
    public Tracker(Composite parent, int style) {
        super(parent, checkStyle(style));
        this.parent = parent;
    }

    /**
     * Constructs a new instance of this class given the display
     * to create it on 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><p>
     * Note: Currently, null can be passed in for the display argument.
     * This has the effect of creating the tracker on the currently active
     * display if there is one. If there is no current display, the
     * tracker is created on a "default" display. <b>Passing in null as
     * the display argument is not considered to be good coding style,
     * and may not be supported in a future release of SWT.</b>
     * </p>
     *
     * @param display the display to create the tracker on
     * @param style the style of control to construct
     *
     * @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 SWT#LEFT
     * @see SWT#RIGHT
     * @see SWT#UP
     * @see SWT#DOWN
     * @see SWT#RESIZE
     */
    public Tracker(Display display, int style) {
        if (display == null)
            display = Display.getCurrent();
        if (display == null)
            display = Display.getDefault();
        if (!display.isValidThread()) {
            error(SWT.ERROR_THREAD_INVALID_ACCESS);
        }
        this.style = checkStyle(style);
        this.display = display;
        reskinWidget();
    }

    /**
     * Adds the listener to the collection of listeners who will
     * be notified when the control is moved or resized, by sending
     * it one of the messages defined in the <code>ControlListener</code>
     * interface.
     *
     * @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 ControlListener
     * @see #removeControlListener
     */
    public void addControlListener(ControlListener listener) {
        checkWidget();
        if (listener == null)
            error(SWT.ERROR_NULL_ARGUMENT);
        TypedListener typedListener = new TypedListener(listener);
        addListener(SWT.Resize, typedListener);
        addListener(SWT.Move, typedListener);
    }

    /**
     * Adds the listener to the collection of listeners who will
     * be notified when keys are pressed and released on the system keyboard, by sending
     * it one of the messages defined in the <code>KeyListener</code>
     * interface.
     *
     * @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 KeyListener
     * @see #removeKeyListener
     */
    public void addKeyListener(KeyListener listener) {
        checkWidget();
        if (listener == null)
            error(SWT.ERROR_NULL_ARGUMENT);
        TypedListener typedListener = new TypedListener(listener);
        addListener(SWT.KeyUp, typedListener);
        addListener(SWT.KeyDown, typedListener);
    }

    Point adjustMoveCursor() {
        if (bounds == null)
            return null;
        int newX = bounds.x + bounds.width / 2;
        int newY = bounds.y;
        POINT pt = new POINT();
        pt.x = newX;
        pt.y = newY;
        /*
         * Convert to screen coordinates iff needed
         */
        if (parent != null) {
            OS.ClientToScreen(parent.handle, pt);
        }
        OS.SetCursorPos(pt.x, pt.y);
        return new Point(pt.x, pt.y);
    }

    Point adjustResizeCursor() {
        if (bounds == null)
            return null;
        int newX, newY;

        if ((cursorOrientation & SWT.LEFT) != 0) {
            newX = bounds.x;
        } else if ((cursorOrientation & SWT.RIGHT) != 0) {
            newX = bounds.x + bounds.width;
        } else {
            newX = bounds.x + bounds.width / 2;
        }

        if ((cursorOrientation & SWT.UP) != 0) {
            newY = bounds.y;
        } else if ((cursorOrientation & SWT.DOWN) != 0) {
            newY = bounds.y + bounds.height;
        } else {
            newY = bounds.y + bounds.height / 2;
        }

        POINT pt = new POINT();
        pt.x = newX;
        pt.y = newY;
        /*
         * Convert to screen coordinates iff needed
         */
        if (parent != null) {
            OS.ClientToScreen(parent.handle, pt);
        }
        OS.SetCursorPos(pt.x, pt.y);

        /*
        * If the client has not provided a custom cursor then determine
        * the appropriate resize cursor.
        */
        if (clientCursor == null) {
            long newCursor = 0;
            switch (cursorOrientation) {
            case SWT.UP:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZENS);
                break;
            case SWT.DOWN:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZENS);
                break;
            case SWT.LEFT:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZEWE);
                break;
            case SWT.RIGHT:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZEWE);
                break;
            case SWT.LEFT | SWT.UP:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZENWSE);
                break;
            case SWT.RIGHT | SWT.DOWN:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZENWSE);
                break;
            case SWT.LEFT | SWT.DOWN:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZENESW);
                break;
            case SWT.RIGHT | SWT.UP:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZENESW);
                break;
            default:
                newCursor = OS.LoadCursor(0, OS.IDC_SIZEALL);
                break;
            }
            OS.SetCursor(newCursor);
            if (resizeCursor != 0) {
                OS.DestroyCursor(resizeCursor);
            }
            resizeCursor = newCursor;
        }

        return new Point(pt.x, pt.y);
    }

    static int checkStyle(int style) {
        if ((style & (SWT.LEFT | SWT.RIGHT | SWT.UP | SWT.DOWN)) == 0) {
            style |= SWT.LEFT | SWT.RIGHT | SWT.UP | SWT.DOWN;
        }
        return style;
    }

    /**
     * Stops displaying the tracker rectangles.  Note that this is not considered
     * to be a cancelation by the user.
     *
     * @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 close() {
        checkWidget();
        tracking = false;
    }

    Rectangle computeBounds() {
        if (rectangles.length == 0)
            return null;
        int xMin = rectangles[0].x;
        int yMin = rectangles[0].y;
        int xMax = rectangles[0].x + rectangles[0].width;
        int yMax = rectangles[0].y + rectangles[0].height;

        for (int i = 1; i < rectangles.length; i++) {
            if (rectangles[i].x < xMin)
                xMin = rectangles[i].x;
            if (rectangles[i].y < yMin)
                yMin = rectangles[i].y;
            int rectRight = rectangles[i].x + rectangles[i].width;
            if (rectRight > xMax)
                xMax = rectRight;
            int rectBottom = rectangles[i].y + rectangles[i].height;
            if (rectBottom > yMax)
                yMax = rectBottom;
        }

        return new Rectangle(xMin, yMin, xMax - xMin, yMax - yMin);
    }

    Rectangle[] computeProportions(Rectangle[] rects) {
        Rectangle[] result = new Rectangle[rects.length];
        bounds = computeBounds();
        if (bounds != null) {
            for (int i = 0; i < rects.length; i++) {
                int x = 0, y = 0, width = 0, height = 0;
                if (bounds.width != 0) {
                    x = (rects[i].x - bounds.x) * 100 / bounds.width;
                    width = rects[i].width * 100 / bounds.width;
                } else {
                    width = 100;
                }
                if (bounds.height != 0) {
                    y = (rects[i].y - bounds.y) * 100 / bounds.height;
                    height = rects[i].height * 100 / bounds.height;
                } else {
                    height = 100;
                }
                result[i] = new Rectangle(x, y, width, height);
            }
        }
        return result;
    }

    /**
     * Draw the rectangles displayed by the tracker.
     */
    void drawRectangles(Rectangle[] rects, boolean stippled) {
        if (hwndOpaque != 0) {
            RECT rect1 = new RECT();
            int bandWidth = stippled ? 3 : 1;
            for (int i = 0; i < rects.length; i++) {
                Rectangle rect = rects[i];
                rect1.left = rect.x - bandWidth;
                rect1.top = rect.y - bandWidth;
                rect1.right = rect.x + rect.width + bandWidth * 2;
                rect1.bottom = rect.y + rect.height + bandWidth * 2;
                OS.MapWindowPoints(0, hwndOpaque, rect1, 2);
                OS.RedrawWindow(hwndOpaque, rect1, 0, OS.RDW_INVALIDATE);
            }
            return;
        }
        int bandWidth = 1;
        long hwndTrack = parent == null ? OS.GetDesktopWindow() : parent.handle;
        long hDC = OS.GetDCEx(hwndTrack, 0, OS.DCX_CACHE);
        long hBitmap = 0, hBrush = 0, oldBrush = 0;
        if (stippled) {
            bandWidth = 3;
            byte[] bits = { -86, 0, 85, 0, -86, 0, 85, 0, -86, 0, 85, 0, -86, 0, 85, 0 };
            hBitmap = OS.CreateBitmap(8, 8, 1, 1, bits);
            hBrush = OS.CreatePatternBrush(hBitmap);
            oldBrush = OS.SelectObject(hDC, hBrush);
        }
        for (int i = 0; i < rects.length; i++) {
            Rectangle rect = rects[i];
            OS.PatBlt(hDC, rect.x, rect.y, rect.width, bandWidth, OS.PATINVERT);
            OS.PatBlt(hDC, rect.x, rect.y + bandWidth, bandWidth, rect.height - (bandWidth * 2), OS.PATINVERT);
            OS.PatBlt(hDC, rect.x + rect.width - bandWidth, rect.y + bandWidth, bandWidth,
                    rect.height - (bandWidth * 2), OS.PATINVERT);
            OS.PatBlt(hDC, rect.x, rect.y + rect.height - bandWidth, rect.width, bandWidth, OS.PATINVERT);
        }
        if (stippled) {
            OS.SelectObject(hDC, oldBrush);
            OS.DeleteObject(hBrush);
            OS.DeleteObject(hBitmap);
        }
        OS.ReleaseDC(hwndTrack, hDC);
    }

    /**
     * Returns the bounds that are being drawn, expressed relative to the parent
     * widget.  If the parent is a <code>Display</code> then these are screen
     * coordinates.
     *
     * @return the bounds of the Rectangles being drawn
     *
     * @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 Rectangle[] getRectangles() {
        checkWidget();
        Rectangle[] result = getRectanglesInPixels();
        for (int i = 0; i < result.length; i++) {
            result[i] = DPIUtil.autoScaleDown(result[i]);
        }
        return result;
    }

    Rectangle[] getRectanglesInPixels() {
        Rectangle[] result = new Rectangle[rectangles.length];
        for (int i = 0; i < rectangles.length; i++) {
            Rectangle current = rectangles[i];
            result[i] = new Rectangle(current.x, current.y, current.width, current.height);
        }
        return result;
    }

    /**
     * Returns <code>true</code> if the rectangles are drawn with a stippled line, <code>false</code> otherwise.
     *
     * @return the stippled effect of the rectangles
     *
     * @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 getStippled() {
        checkWidget();
        return stippled;
    }

    void moveRectangles(int xChange, int yChange) {
        if (bounds == null)
            return;
        if (xChange < 0 && ((style & SWT.LEFT) == 0))
            xChange = 0;
        if (xChange > 0 && ((style & SWT.RIGHT) == 0))
            xChange = 0;
        if (yChange < 0 && ((style & SWT.UP) == 0))
            yChange = 0;
        if (yChange > 0 && ((style & SWT.DOWN) == 0))
            yChange = 0;
        if (xChange == 0 && yChange == 0)
            return;
        bounds.x += xChange;
        bounds.y += yChange;
        for (int i = 0; i < rectangles.length; i++) {
            rectangles[i].x += xChange;
            rectangles[i].y += yChange;
        }
    }

    /**
     * Displays the Tracker rectangles for manipulation by the user.  Returns when
     * the user has either finished manipulating the rectangles or has cancelled the
     * Tracker.
     *
     * @return <code>true</code> if the user did not cancel the Tracker, <code>false</code> otherwise
     *
     * @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 open() {
        checkWidget();
        cancelled = false;
        tracking = true;

        /*
        * If exactly one of UP/DOWN is specified as a style then set the cursor
        * orientation accordingly (the same is done for LEFT/RIGHT styles below).
        */
        int vStyle = style & (SWT.UP | SWT.DOWN);
        if (vStyle == SWT.UP || vStyle == SWT.DOWN) {
            cursorOrientation |= vStyle;
        }
        int hStyle = style & (SWT.LEFT | SWT.RIGHT);
        if (hStyle == SWT.LEFT || hStyle == SWT.RIGHT) {
            cursorOrientation |= hStyle;
        }

        Callback newProc = null;
        boolean mouseDown = OS.GetKeyState(OS.VK_LBUTTON) < 0;
        /*
        * Bug in Vista. Drawing directly to the screen with XOR does not
        * perform well. The fix is to draw on layered window instead.
        *
        * Note that one window (almost opaque) is used for catching all events and a
        * second window is used for drawing the rectangles.
        */
        if (parent == null) {
            Rectangle bounds = display.getBoundsInPixels();
            hwndTransparent = OS.CreateWindowEx(OS.WS_EX_LAYERED | OS.WS_EX_NOACTIVATE | OS.WS_EX_TOOLWINDOW,
                    display.windowClass, null, OS.WS_POPUP, bounds.x, bounds.y, bounds.width, bounds.height, 0, 0,
                    OS.GetModuleHandle(null), null);
            OS.SetLayeredWindowAttributes(hwndTransparent, 0, (byte) 0x01, OS.LWA_ALPHA);
            hwndOpaque = OS.CreateWindowEx(OS.WS_EX_LAYERED | OS.WS_EX_NOACTIVATE | OS.WS_EX_TOOLWINDOW,
                    display.windowClass, null, OS.WS_POPUP, bounds.x, bounds.y, bounds.width, bounds.height,
                    hwndTransparent, 0, OS.GetModuleHandle(null), null);
            OS.SetLayeredWindowAttributes(hwndOpaque, 0xFFFFFF, (byte) 0, OS.LWA_COLORKEY | OS.LWA_ALPHA);
            drawn = false;
            newProc = new Callback(this, "transparentProc", 4); //$NON-NLS-1$
            long newProcAddress = newProc.getAddress();
            if (newProcAddress == 0)
                error(SWT.ERROR_NO_MORE_CALLBACKS);
            oldTransparentProc = OS.GetWindowLongPtr(hwndTransparent, OS.GWLP_WNDPROC);
            OS.SetWindowLongPtr(hwndTransparent, OS.GWLP_WNDPROC, newProcAddress);
            oldOpaqueProc = OS.GetWindowLongPtr(hwndOpaque, OS.GWLP_WNDPROC);
            OS.SetWindowLongPtr(hwndOpaque, OS.GWLP_WNDPROC, newProcAddress);
            OS.ShowWindow(hwndTransparent, OS.SW_SHOWNOACTIVATE);
            OS.ShowWindow(hwndOpaque, OS.SW_SHOWNOACTIVATE);
        } else {
            /*
            * If this tracker is being created without a mouse drag then
            * we need to create a transparent window that fills the screen
            * in order to get all mouse/keyboard events that occur
            * outside of our visible windows (ie.- over the desktop).
            */
            if (!mouseDown) {
                Rectangle bounds = display.getBoundsInPixels();
                hwndTransparent = OS.CreateWindowEx(OS.WS_EX_TRANSPARENT, display.windowClass, null, OS.WS_POPUP,
                        bounds.x, bounds.y, bounds.width, bounds.height, 0, 0, OS.GetModuleHandle(null), null);
                newProc = new Callback(this, "transparentProc", 4); //$NON-NLS-1$
                long newProcAddress = newProc.getAddress();
                if (newProcAddress == 0)
                    error(SWT.ERROR_NO_MORE_CALLBACKS);
                oldTransparentProc = OS.GetWindowLongPtr(hwndTransparent, OS.GWLP_WNDPROC);
                OS.SetWindowLongPtr(hwndTransparent, OS.GWLP_WNDPROC, newProcAddress);
                OS.ShowWindow(hwndTransparent, OS.SW_SHOWNOACTIVATE);
            }
        }

        update();
        drawRectangles(rectangles, stippled);
        Point cursorPos = null;
        if (mouseDown) {
            POINT pt = new POINT();
            OS.GetCursorPos(pt);
            cursorPos = new Point(pt.x, pt.y);
        } else {
            if ((style & SWT.RESIZE) != 0) {
                cursorPos = adjustResizeCursor();
            } else {
                cursorPos = adjustMoveCursor();
            }
        }
        if (cursorPos != null) {
            oldX = cursorPos.x;
            oldY = cursorPos.y;
        }

        Display display = this.display;
        try {
            /* Tracker behaves like a Dialog with its own OS event loop. */
            MSG msg = new MSG();
            while (tracking && !cancelled) {
                if (parent != null && parent.isDisposed())
                    break;
                display.runSkin();
                display.runDeferredLayouts();
                display.sendPreExternalEventDispatchEvent();
                OS.GetMessage(msg, 0, 0, 0);
                display.sendPostExternalEventDispatchEvent();
                OS.TranslateMessage(msg);
                switch (msg.message) {
                case OS.WM_LBUTTONUP:
                case OS.WM_MOUSEMOVE:
                    wmMouse(msg.message, msg.wParam, msg.lParam);
                    break;
                case OS.WM_IME_CHAR:
                    wmIMEChar(msg.hwnd, msg.wParam, msg.lParam);
                    break;
                case OS.WM_CHAR:
                    wmChar(msg.hwnd, msg.wParam, msg.lParam);
                    break;
                case OS.WM_KEYDOWN:
                    wmKeyDown(msg.hwnd, msg.wParam, msg.lParam);
                    break;
                case OS.WM_KEYUP:
                    wmKeyUp(msg.hwnd, msg.wParam, msg.lParam);
                    break;
                case OS.WM_SYSCHAR:
                    wmSysChar(msg.hwnd, msg.wParam, msg.lParam);
                    break;
                case OS.WM_SYSKEYDOWN:
                    wmSysKeyDown(msg.hwnd, msg.wParam, msg.lParam);
                    break;
                case OS.WM_SYSKEYUP:
                    wmSysKeyUp(msg.hwnd, msg.wParam, msg.lParam);
                    break;
                }
                if (OS.WM_KEYFIRST <= msg.message && msg.message <= OS.WM_KEYLAST)
                    continue;
                if (OS.WM_MOUSEFIRST <= msg.message && msg.message <= OS.WM_MOUSELAST)
                    continue;
                if (hwndOpaque == 0) {
                    if (msg.message == OS.WM_PAINT) {
                        update();
                        drawRectangles(rectangles, stippled);
                    }
                }
                OS.DispatchMessage(msg);
                if (hwndOpaque == 0) {
                    if (msg.message == OS.WM_PAINT) {
                        drawRectangles(rectangles, stippled);
                    }
                }
                display.runAsyncMessages(false);
            }
            if (mouseDown)
                OS.ReleaseCapture();
            if (!isDisposed()) {
                update();
                drawRectangles(rectangles, stippled);
            }
        } finally {
            /*
            * Cleanup: If a transparent window was created in order to capture events then
            * destroy it and its callback object now.
            */
            if (hwndTransparent != 0) {
                OS.DestroyWindow(hwndTransparent);
                hwndTransparent = 0;
            }
            hwndOpaque = 0;
            if (newProc != null) {
                newProc.dispose();
                oldTransparentProc = oldOpaqueProc = 0;
            }
            /*
            * Cleanup: If this tracker was resizing then the last cursor that it created
            * needs to be destroyed.
            */
            if (resizeCursor != 0) {
                OS.DestroyCursor(resizeCursor);
                resizeCursor = 0;
            }
        }
        tracking = false;
        return !cancelled;
    }

    @Override
    void releaseWidget() {
        super.releaseWidget();
        parent = null;
        rectangles = proportions = null;
        bounds = null;
    }

    /**
     * Removes the listener from the collection of listeners who will
     * be notified when the control is moved or resized.
     *
     * @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 ControlListener
     * @see #addControlListener
     */
    public void removeControlListener(ControlListener listener) {
        checkWidget();
        if (listener == null)
            error(SWT.ERROR_NULL_ARGUMENT);
        if (eventTable == null)
            return;
        eventTable.unhook(SWT.Resize, listener);
        eventTable.unhook(SWT.Move, listener);
    }

    /**
     * Removes the listener from the collection of listeners who will
     * be notified when keys are pressed and released on the system keyboard.
     *
     * @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 KeyListener
     * @see #addKeyListener
     */
    public void removeKeyListener(KeyListener listener) {
        checkWidget();
        if (listener == null)
            error(SWT.ERROR_NULL_ARGUMENT);
        if (eventTable == null)
            return;
        eventTable.unhook(SWT.KeyUp, listener);
        eventTable.unhook(SWT.KeyDown, listener);
    }

    void resizeRectangles(int xChange, int yChange) {
        if (bounds == null)
            return;
        /*
        * If the cursor orientation has not been set in the orientation of
        * this change then try to set it here.
        */
        if (xChange < 0 && ((style & SWT.LEFT) != 0) && ((cursorOrientation & SWT.RIGHT) == 0)) {
            cursorOrientation |= SWT.LEFT;
        }
        if (xChange > 0 && ((style & SWT.RIGHT) != 0) && ((cursorOrientation & SWT.LEFT) == 0)) {
            cursorOrientation |= SWT.RIGHT;
        }
        if (yChange < 0 && ((style & SWT.UP) != 0) && ((cursorOrientation & SWT.DOWN) == 0)) {
            cursorOrientation |= SWT.UP;
        }
        if (yChange > 0 && ((style & SWT.DOWN) != 0) && ((cursorOrientation & SWT.UP) == 0)) {
            cursorOrientation |= SWT.DOWN;
        }

        /*
         * If the bounds will flip about the x or y axis then apply the adjustment
         * up to the axis (ie.- where bounds width/height becomes 0), change the
         * cursor's orientation accordingly, and flip each Rectangle's origin (only
         * necessary for > 1 Rectangles)
         */
        if ((cursorOrientation & SWT.LEFT) != 0) {
            if (xChange > bounds.width) {
                if ((style & SWT.RIGHT) == 0)
                    return;
                cursorOrientation |= SWT.RIGHT;
                cursorOrientation &= ~SWT.LEFT;
                bounds.x += bounds.width;
                xChange -= bounds.width;
                bounds.width = 0;
                if (proportions.length > 1) {
                    for (int i = 0; i < proportions.length; i++) {
                        Rectangle proportion = proportions[i];
                        proportion.x = 100 - proportion.x - proportion.width;
                    }
                }
            }
        } else if ((cursorOrientation & SWT.RIGHT) != 0) {
            if (bounds.width < -xChange) {
                if ((style & SWT.LEFT) == 0)
                    return;
                cursorOrientation |= SWT.LEFT;
                cursorOrientation &= ~SWT.RIGHT;
                xChange += bounds.width;
                bounds.width = 0;
                if (proportions.length > 1) {
                    for (int i = 0; i < proportions.length; i++) {
                        Rectangle proportion = proportions[i];
                        proportion.x = 100 - proportion.x - proportion.width;
                    }
                }
            }
        }
        if ((cursorOrientation & SWT.UP) != 0) {
            if (yChange > bounds.height) {
                if ((style & SWT.DOWN) == 0)
                    return;
                cursorOrientation |= SWT.DOWN;
                cursorOrientation &= ~SWT.UP;
                bounds.y += bounds.height;
                yChange -= bounds.height;
                bounds.height = 0;
                if (proportions.length > 1) {
                    for (int i = 0; i < proportions.length; i++) {
                        Rectangle proportion = proportions[i];
                        proportion.y = 100 - proportion.y - proportion.height;
                    }
                }
            }
        } else if ((cursorOrientation & SWT.DOWN) != 0) {
            if (bounds.height < -yChange) {
                if ((style & SWT.UP) == 0)
                    return;
                cursorOrientation |= SWT.UP;
                cursorOrientation &= ~SWT.DOWN;
                yChange += bounds.height;
                bounds.height = 0;
                if (proportions.length > 1) {
                    for (int i = 0; i < proportions.length; i++) {
                        Rectangle proportion = proportions[i];
                        proportion.y = 100 - proportion.y - proportion.height;
                    }
                }
            }
        }

        // apply the bounds adjustment
        if ((cursorOrientation & SWT.LEFT) != 0) {
            bounds.x += xChange;
            bounds.width -= xChange;
        } else if ((cursorOrientation & SWT.RIGHT) != 0) {
            bounds.width += xChange;
        }
        if ((cursorOrientation & SWT.UP) != 0) {
            bounds.y += yChange;
            bounds.height -= yChange;
        } else if ((cursorOrientation & SWT.DOWN) != 0) {
            bounds.height += yChange;
        }

        Rectangle[] newRects = new Rectangle[rectangles.length];
        for (int i = 0; i < rectangles.length; i++) {
            Rectangle proportion = proportions[i];
            newRects[i] = new Rectangle(proportion.x * bounds.width / 100 + bounds.x,
                    proportion.y * bounds.height / 100 + bounds.y, proportion.width * bounds.width / 100,
                    proportion.height * bounds.height / 100);
        }
        rectangles = newRects;
    }

    /**
     * Sets the <code>Cursor</code> of the Tracker.  If this cursor is <code>null</code>
     * then the cursor reverts to the default.
     *
     * @param newCursor the new <code>Cursor</code> to display
     *
     * @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 setCursor(Cursor newCursor) {
        checkWidget();
        clientCursor = newCursor;
        if (newCursor != null) {
            if (inEvent)
                OS.SetCursor(clientCursor.handle);
        }
    }

    /**
     * Specifies the rectangles that should be drawn, expressed relative to the parent
     * widget.  If the parent is a Display then these are screen coordinates.
     *
     * @param rectangles the bounds of the rectangles to be drawn
     *
     * @exception IllegalArgumentException <ul>
     *    <li>ERROR_NULL_ARGUMENT - if the set of rectangles is null or contains a null rectangle</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 setRectangles(Rectangle[] rectangles) {
        checkWidget();
        if (rectangles == null)
            error(SWT.ERROR_NULL_ARGUMENT);
        Rectangle[] rectanglesInPixels = new Rectangle[rectangles.length];
        for (int i = 0; i < rectangles.length; i++) {
            rectanglesInPixels[i] = DPIUtil.autoScaleUp(rectangles[i]);
        }
        setRectanglesInPixels(rectanglesInPixels);
    }

    void setRectanglesInPixels(Rectangle[] rectangles) {
        this.rectangles = new Rectangle[rectangles.length];
        for (int i = 0; i < rectangles.length; i++) {
            Rectangle current = rectangles[i];
            if (current == null)
                error(SWT.ERROR_NULL_ARGUMENT);
            this.rectangles[i] = new Rectangle(current.x, current.y, current.width, current.height);
        }
        proportions = computeProportions(rectangles);
    }

    /**
     * Changes the appearance of the line used to draw the rectangles.
     *
     * @param stippled <code>true</code> if rectangle should appear stippled
     *
     * @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 setStippled(boolean stippled) {
        checkWidget();
        this.stippled = stippled;
    }

    long transparentProc(long hwnd, long msg, long wParam, long lParam) {
        switch ((int) msg) {
        /*
        * We typically do not want to answer that the transparent window is
        * transparent to hits since doing so negates the effect of having it
        * to grab events.  However, clients of the tracker should not be aware
        * of this transparent window.  Therefore if there is a hit query
        * performed as a result of client code then answer that the transparent
        * window is transparent to hits so that its existence will not impact
        * the client.
        */
        case OS.WM_NCHITTEST:
            if (inEvent)
                return OS.HTTRANSPARENT;
            break;
        case OS.WM_SETCURSOR:
            if (clientCursor != null) {
                OS.SetCursor(clientCursor.handle);
                return 1;
            }
            if (resizeCursor != 0) {
                OS.SetCursor(resizeCursor);
                return 1;
            }
            break;
        case OS.WM_PAINT:
            if (hwndOpaque == hwnd) {
                PAINTSTRUCT ps = new PAINTSTRUCT();
                long hDC = OS.BeginPaint(hwnd, ps);
                long hBitmap = 0, hBrush = 0, oldBrush = 0;
                long transparentBrush = OS.CreateSolidBrush(0xFFFFFF);
                oldBrush = OS.SelectObject(hDC, transparentBrush);
                OS.PatBlt(hDC, ps.left, ps.top, ps.right - ps.left, ps.bottom - ps.top, OS.PATCOPY);
                OS.SelectObject(hDC, oldBrush);
                OS.DeleteObject(transparentBrush);
                int bandWidth = 1;
                if (stippled) {
                    bandWidth = 3;
                    byte[] bits = { -86, 0, 85, 0, -86, 0, 85, 0, -86, 0, 85, 0, -86, 0, 85, 0 };
                    hBitmap = OS.CreateBitmap(8, 8, 1, 1, bits);
                    hBrush = OS.CreatePatternBrush(hBitmap);
                    oldBrush = OS.SelectObject(hDC, hBrush);
                    OS.SetBkColor(hDC, 0xF0F0F0);
                } else {
                    oldBrush = OS.SelectObject(hDC, OS.GetStockObject(OS.BLACK_BRUSH));
                }
                Rectangle[] rects = this.rectangles;
                RECT rect1 = new RECT();
                for (int i = 0; i < rects.length; i++) {
                    Rectangle rect = rects[i];
                    rect1.left = rect.x;
                    rect1.top = rect.y;
                    rect1.right = rect.x + rect.width;
                    rect1.bottom = rect.y + rect.height;
                    OS.MapWindowPoints(0, hwndOpaque, rect1, 2);
                    int width = rect1.right - rect1.left;
                    int height = rect1.bottom - rect1.top;
                    OS.PatBlt(hDC, rect1.left, rect1.top, width, bandWidth, OS.PATCOPY);
                    OS.PatBlt(hDC, rect1.left, rect1.top + bandWidth, bandWidth, height - (bandWidth * 2),
                            OS.PATCOPY);
                    OS.PatBlt(hDC, rect1.right - bandWidth, rect1.top + bandWidth, bandWidth,
                            height - (bandWidth * 2), OS.PATCOPY);
                    OS.PatBlt(hDC, rect1.left, rect1.bottom - bandWidth, width, bandWidth, OS.PATCOPY);
                }
                OS.SelectObject(hDC, oldBrush);
                if (stippled) {
                    OS.DeleteObject(hBrush);
                    OS.DeleteObject(hBitmap);
                }
                OS.EndPaint(hwnd, ps);
                if (!drawn) {
                    OS.SetLayeredWindowAttributes(hwndOpaque, 0xFFFFFF, (byte) 0xFF,
                            OS.LWA_COLORKEY | OS.LWA_ALPHA);
                    drawn = true;
                }
                return 0;
            }
        }
        return OS.CallWindowProc(hwnd == hwndTransparent ? oldTransparentProc : oldOpaqueProc, hwnd, (int) msg,
                wParam, lParam);
    }

    void update() {
        if (hwndOpaque != 0)
            return;
        if (parent != null) {
            if (parent.isDisposed())
                return;
            Shell shell = parent.getShell();
            shell.update(true);
        } else {
            display.update();
        }
    }

    @Override
    LRESULT wmKeyDown(long hwnd, long wParam, long lParam) {
        LRESULT result = super.wmKeyDown(hwnd, wParam, lParam);
        if (result != null)
            return result;
        boolean isMirrored = parent != null && (parent.style & SWT.MIRRORED) != 0;
        int stepSize = OS.GetKeyState(OS.VK_CONTROL) < 0 ? STEPSIZE_SMALL : STEPSIZE_LARGE;
        int xChange = 0, yChange = 0;
        switch ((int) wParam) {
        case OS.VK_ESCAPE:
            cancelled = true;
            tracking = false;
            break;
        case OS.VK_RETURN:
            tracking = false;
            break;
        case OS.VK_LEFT:
            xChange = isMirrored ? stepSize : -stepSize;
            break;
        case OS.VK_RIGHT:
            xChange = isMirrored ? -stepSize : stepSize;
            break;
        case OS.VK_UP:
            yChange = -stepSize;
            break;
        case OS.VK_DOWN:
            yChange = stepSize;
            break;
        }
        if (xChange != 0 || yChange != 0) {
            Rectangle[] oldRectangles = rectangles;
            boolean oldStippled = stippled;
            Rectangle[] rectsToErase = new Rectangle[rectangles.length];
            for (int i = 0; i < rectangles.length; i++) {
                Rectangle current = rectangles[i];
                rectsToErase[i] = new Rectangle(current.x, current.y, current.width, current.height);
            }
            Event event = new Event();
            event.setLocationInPixels(oldX + xChange, oldY + yChange);
            Point cursorPos;
            if ((style & SWT.RESIZE) != 0) {
                resizeRectangles(xChange, yChange);
                inEvent = true;
                sendEvent(SWT.Resize, event);
                inEvent = false;
                /*
                * It is possible (but unlikely) that application
                * code could have disposed the widget in the resize
                * event.  If this happens return false to indicate
                * that the tracking has failed.
                */
                if (isDisposed()) {
                    cancelled = true;
                    return LRESULT.ONE;
                }
                boolean draw = false;
                /*
                 * It is possible that application code could have
                 * changed the rectangles in the resize event.  If this
                 * happens then only redraw the tracker if the rectangle
                 * values have changed.
                 */
                if (rectangles != oldRectangles) {
                    int length = rectangles.length;
                    if (length != rectsToErase.length) {
                        draw = true;
                    } else {
                        for (int i = 0; i < length; i++) {
                            if (!rectangles[i].equals(rectsToErase[i])) {
                                draw = true;
                                break;
                            }
                        }
                    }
                } else {
                    draw = true;
                }
                if (draw) {
                    drawRectangles(rectsToErase, oldStippled);
                    update();
                    drawRectangles(rectangles, stippled);
                }
                cursorPos = adjustResizeCursor();
            } else {
                moveRectangles(xChange, yChange);
                inEvent = true;
                sendEvent(SWT.Move, event);
                inEvent = false;
                /*
                * It is possible (but unlikely) that application
                * code could have disposed the widget in the move
                * event.  If this happens return false to indicate
                * that the tracking has failed.
                */
                if (isDisposed()) {
                    cancelled = true;
                    return LRESULT.ONE;
                }
                boolean draw = false;
                /*
                 * It is possible that application code could have
                 * changed the rectangles in the move event.  If this
                 * happens then only redraw the tracker if the rectangle
                 * values have changed.
                 */
                if (rectangles != oldRectangles) {
                    int length = rectangles.length;
                    if (length != rectsToErase.length) {
                        draw = true;
                    } else {
                        for (int i = 0; i < length; i++) {
                            if (!rectangles[i].equals(rectsToErase[i])) {
                                draw = true;
                                break;
                            }
                        }
                    }
                } else {
                    draw = true;
                }
                if (draw) {
                    drawRectangles(rectsToErase, oldStippled);
                    update();
                    drawRectangles(rectangles, stippled);
                }
                cursorPos = adjustMoveCursor();
            }
            if (cursorPos != null) {
                oldX = cursorPos.x;
                oldY = cursorPos.y;
            }
        }
        return result;
    }

    @Override
    LRESULT wmSysKeyDown(long hwnd, long wParam, long lParam) {
        LRESULT result = super.wmSysKeyDown(hwnd, wParam, lParam);
        if (result != null)
            return result;
        cancelled = true;
        tracking = false;
        return result;
    }

    LRESULT wmMouse(int message, long wParam, long lParam) {
        boolean isMirrored = parent != null && (parent.style & SWT.MIRRORED) != 0;
        int newPos = OS.GetMessagePos();
        int newX = OS.GET_X_LPARAM(newPos);
        int newY = OS.GET_Y_LPARAM(newPos);
        if (newX != oldX || newY != oldY) {
            Rectangle[] oldRectangles = rectangles;
            boolean oldStippled = stippled;
            Rectangle[] rectsToErase = new Rectangle[rectangles.length];
            for (int i = 0; i < rectangles.length; i++) {
                Rectangle current = rectangles[i];
                rectsToErase[i] = new Rectangle(current.x, current.y, current.width, current.height);
            }
            Event event = new Event();
            event.setLocationInPixels(newX, newY);
            if ((style & SWT.RESIZE) != 0) {
                if (isMirrored) {
                    resizeRectangles(oldX - newX, newY - oldY);
                } else {
                    resizeRectangles(newX - oldX, newY - oldY);
                }
                inEvent = true;
                sendEvent(SWT.Resize, event);
                inEvent = false;
                /*
                * It is possible (but unlikely), that application
                * code could have disposed the widget in the resize
                * event.  If this happens, return false to indicate
                * that the tracking has failed.
                */
                if (isDisposed()) {
                    cancelled = true;
                    return LRESULT.ONE;
                }
                boolean draw = false;
                /*
                 * It is possible that application code could have
                 * changed the rectangles in the resize event.  If this
                 * happens then only redraw the tracker if the rectangle
                 * values have changed.
                 */
                if (rectangles != oldRectangles) {
                    int length = rectangles.length;
                    if (length != rectsToErase.length) {
                        draw = true;
                    } else {
                        for (int i = 0; i < length; i++) {
                            if (!rectangles[i].equals(rectsToErase[i])) {
                                draw = true;
                                break;
                            }
                        }
                    }
                } else {
                    draw = true;
                }
                if (draw) {
                    drawRectangles(rectsToErase, oldStippled);
                    update();
                    drawRectangles(rectangles, stippled);
                }
                Point cursorPos = adjustResizeCursor();
                if (cursorPos != null) {
                    newX = cursorPos.x;
                    newY = cursorPos.y;
                }
            } else {
                if (isMirrored) {
                    moveRectangles(oldX - newX, newY - oldY);
                } else {
                    moveRectangles(newX - oldX, newY - oldY);
                }
                inEvent = true;
                sendEvent(SWT.Move, event);
                inEvent = false;
                /*
                * It is possible (but unlikely), that application
                * code could have disposed the widget in the move
                * event.  If this happens, return false to indicate
                * that the tracking has failed.
                */
                if (isDisposed()) {
                    cancelled = true;
                    return LRESULT.ONE;
                }
                boolean draw = false;
                /*
                 * It is possible that application code could have
                 * changed the rectangles in the move event.  If this
                 * happens then only redraw the tracker if the rectangle
                 * values have changed.
                 */
                if (rectangles != oldRectangles) {
                    int length = rectangles.length;
                    if (length != rectsToErase.length) {
                        draw = true;
                    } else {
                        for (int i = 0; i < length; i++) {
                            if (!rectangles[i].equals(rectsToErase[i])) {
                                draw = true;
                                break;
                            }
                        }
                    }
                } else {
                    draw = true;
                }
                if (draw) {
                    drawRectangles(rectsToErase, oldStippled);
                    update();
                    drawRectangles(rectangles, stippled);
                }
            }
            oldX = newX;
            oldY = newY;
        }
        tracking = message != OS.WM_LBUTTONUP;
        return null;
    }

}