cutting v0.0.1
[fanfix.git] / src / jexer / TApplication.java
index b2ee5071a74284b42a6068efed531c4dc3c90039..4c55aad9a70f20f83d63fdfb49e9b6b5df8c0e9f 100644 (file)
@@ -34,8 +34,12 @@ import java.io.InputStream;
 import java.io.OutputStream;
 import java.io.UnsupportedEncodingException;
 import java.util.Collections;
+import java.util.Date;
+import java.util.HashMap;
+import java.util.ArrayList;
 import java.util.LinkedList;
 import java.util.List;
+import java.util.Map;
 
 import jexer.bits.CellAttributes;
 import jexer.bits.ColorTheme;
@@ -47,6 +51,7 @@ import jexer.event.TMenuEvent;
 import jexer.event.TMouseEvent;
 import jexer.event.TResizeEvent;
 import jexer.backend.Backend;
+import jexer.backend.AWTBackend;
 import jexer.backend.ECMA48Backend;
 import jexer.io.Screen;
 import jexer.menu.TMenu;
@@ -59,6 +64,107 @@ import static jexer.TKeypress.*;
  */
 public class TApplication {
 
+    /**
+     * WidgetEventHandler is the main event consumer loop.  There are at most
+     * two such threads in existence: the primary for normal case and a
+     * secondary that is used for TMessageBox, TInputBox, and similar.
+     */
+    private class WidgetEventHandler implements Runnable {
+        /**
+         * The main application.
+         */
+        private TApplication application;
+
+        /**
+         * Whether or not this WidgetEventHandler is the primary or secondary
+         * thread.
+         */
+        private boolean primary = true;
+
+        /**
+         * Public constructor.
+         *
+         * @param application the main application
+         * @param primary if true, this is the primary event handler thread
+         */
+        public WidgetEventHandler(final TApplication application,
+            final boolean primary) {
+
+            this.application = application;
+            this.primary = primary;
+        }
+
+        /**
+         * The consumer loop.
+         */
+        public void run() {
+
+            // Loop forever
+            while (!application.quit) {
+
+                // Wait until application notifies me
+                while (!application.quit) {
+                    try {
+                        synchronized (application.drainEventQueue) {
+                            if (application.drainEventQueue.size() > 0) {
+                                break;
+                            }
+                        }
+                        synchronized (application) {
+                            application.wait();
+                            if ((!primary)
+                                && (application.secondaryEventReceiver == null)
+                            ) {
+                                // Secondary thread, time to exit
+                                return;
+                            }
+                            break;
+                        }
+                    } catch (InterruptedException e) {
+                        // SQUASH
+                    }
+                }
+
+                // Pull all events off the queue
+                for (;;) {
+                    TInputEvent event = null;
+                    synchronized (application.drainEventQueue) {
+                        if (application.drainEventQueue.size() == 0) {
+                            break;
+                        }
+                        event = application.drainEventQueue.remove(0);
+                    }
+                    if (primary) {
+                        primaryHandleEvent(event);
+                    } else {
+                        secondaryHandleEvent(event);
+                    }
+                    if ((!primary)
+                        && (application.secondaryEventReceiver == null)
+                    ) {
+                        // Secondary thread, time to exit
+                        return;
+                    }
+                }
+            } // while (true) (main runnable loop)
+        }
+    }
+
+    /**
+     * The primary event handler thread.
+     */
+    private WidgetEventHandler primaryEventHandler;
+
+    /**
+     * The secondary event handler thread.
+     */
+    private WidgetEventHandler secondaryEventHandler;
+
+    /**
+     * The widget receiving events from the secondary event handler thread.
+     */
+    private TWidget secondaryEventReceiver;
+
     /**
      * Access to the physical screen, keyboard, and mouse.
      */
@@ -84,9 +190,15 @@ public class TApplication {
     private int mouseY;
 
     /**
-     * Event queue that will be drained by either primary or secondary Fiber.
+     * Event queue that is filled by run().
      */
-    private List<TInputEvent> eventQueue;
+    private List<TInputEvent> fillEventQueue;
+
+    /**
+     * Event queue that will be drained by either primary or secondary
+     * Thread.
+     */
+    private List<TInputEvent> drainEventQueue;
 
     /**
      * Top-level menus in this application.
@@ -103,6 +215,11 @@ public class TApplication {
      */
     private TMenu activeMenu = null;
 
+    /**
+     * Active keyboard accelerators.
+     */
+    private Map<TKeypress, TMenuItem> accelerators;
+
     /**
      * Windows and widgets pull colors from this ColorTheme.
      */
@@ -122,6 +239,11 @@ public class TApplication {
      */
     private List<TWindow> windows;
 
+    /**
+     * Timers that are being ticked.
+     */
+    private List<TTimer> timers;
+
     /**
      * When true, exit the application.
      */
@@ -190,13 +312,39 @@ public class TApplication {
     public TApplication(final InputStream input,
         final OutputStream output) throws UnsupportedEncodingException {
 
-        backend       = new ECMA48Backend(input, output);
-        theme         = new ColorTheme();
-        desktopBottom = getScreen().getHeight() - 1;
-        eventQueue    = new LinkedList<TInputEvent>();
-        windows       = new LinkedList<TWindow>();
-        menus         = new LinkedList<TMenu>();
-        subMenus      = new LinkedList<TMenu>();
+        // AWT is the default backend on Windows unless explicitly overridden
+        // by jexer.AWT.
+        boolean useAWT = false;
+        if (System.getProperty("os.name").startsWith("Windows")) {
+            useAWT = true;
+        }
+        if (System.getProperty("jexer.AWT") != null) {
+            if (System.getProperty("jexer.AWT", "false").equals("true")) {
+                useAWT = true;
+            } else {
+                useAWT = false;
+            }
+        }
+
+
+        if (useAWT) {
+            backend     = new AWTBackend();
+        } else {
+            backend     = new ECMA48Backend(input, output);
+        }
+        theme           = new ColorTheme();
+        desktopBottom   = getScreen().getHeight() - 1;
+        fillEventQueue  = new ArrayList<TInputEvent>();
+        drainEventQueue = new ArrayList<TInputEvent>();
+        windows         = new LinkedList<TWindow>();
+        menus           = new LinkedList<TMenu>();
+        subMenus        = new LinkedList<TMenu>();
+        timers          = new LinkedList<TTimer>();
+        accelerators    = new HashMap<TKeypress, TMenuItem>();
+
+        // Setup the main consumer thread
+        primaryEventHandler = new WidgetEventHandler(this, true);
+        (new Thread(primaryEventHandler)).start();
     }
 
     /**
@@ -315,142 +463,120 @@ public class TApplication {
      * Run this application until it exits.
      */
     public final void run() {
-        List<TInputEvent> events = new LinkedList<TInputEvent>();
-
         while (!quit) {
             // Timeout is in milliseconds, so default timeout after 1 second
             // of inactivity.
             int timeout = getSleepTime(1000);
 
-            if (eventQueue.size() > 0) {
-                // Do not wait if there are definitely events waiting to be
-                // processed or a screen redraw to do.
-                timeout = 0;
+            // See if there are any definitely events waiting to be processed
+            // or a screen redraw to do.  If so, do not wait if there is no
+            // I/O coming in.
+            synchronized (drainEventQueue) {
+                if (drainEventQueue.size() > 0) {
+                    timeout = 0;
+                }
+            }
+            synchronized (fillEventQueue) {
+                if (fillEventQueue.size() > 0) {
+                    timeout = 0;
+                }
             }
 
-            // Pull any pending input events
-            backend.getEvents(events, timeout);
-            metaHandleEvents(events);
-            events.clear();
+            // Pull any pending I/O events
+            backend.getEvents(fillEventQueue, timeout);
+
+            // Dispatch each event to the appropriate handler, one at a time.
+            for (;;) {
+                TInputEvent event = null;
+                synchronized (fillEventQueue) {
+                    if (fillEventQueue.size() == 0) {
+                        break;
+                    }
+                    event = fillEventQueue.remove(0);
+                }
+                metaHandleEvent(event);
+            }
 
             // Process timers and call doIdle()'s
             doIdle();
 
             // Update the screen
-            drawAll();
-        }
-
-        /*
-
-        // Shutdown the fibers
-        eventQueue.length = 0;
-        if (secondaryEventFiber !is null) {
-            assert(secondaryEventReceiver !is null);
-            secondaryEventReceiver = null;
-            if (secondaryEventFiber.state == Fiber.State.HOLD) {
-                // Wake up the secondary handler so that it can exit.
-                secondaryEventFiber.call();
+            synchronized (getScreen()) {
+                drawAll();
             }
         }
 
-        if (primaryEventFiber.state == Fiber.State.HOLD) {
-            // Wake up the primary handler so that it can exit.
-            primaryEventFiber.call();
+        // Shutdown the consumer threads
+        synchronized (this) {
+            this.notifyAll();
         }
-         */
 
         backend.shutdown();
     }
 
     /**
      * Peek at certain application-level events, add to eventQueue, and wake
-     * up the consuming Fiber.
+     * up the consuming Thread.
      *
-     * @param events the input events to consume
+     * @param event the input event to consume
      */
-    private void metaHandleEvents(final List<TInputEvent> events) {
-
-        for (TInputEvent event: events) {
+    private void metaHandleEvent(final TInputEvent event) {
 
-            /*
-            System.err.printf(String.format("metaHandleEvents event: %s\n",
-                    event)); System.err.flush();
-             */
-
-            if (quit) {
-                // Do no more processing if the application is already trying
-                // to exit.
-                return;
-            }
-
-            // DEBUG
-            if (event instanceof TKeypressEvent) {
-                TKeypressEvent keypress = (TKeypressEvent) event;
-                if (keypress.equals(kbAltX)) {
-                    quit = true;
-                    return;
-                }
-            }
-            // DEBUG
-
-            // Special application-wide events -------------------------------
+        /*
+        System.err.printf(String.format("metaHandleEvents event: %s\n",
+                event)); System.err.flush();
+         */
 
-            // Abort everything
-            if (event instanceof TCommandEvent) {
-                TCommandEvent command = (TCommandEvent) event;
-                if (command.getCmd().equals(cmAbort)) {
-                    quit = true;
-                    return;
-                }
-            }
+        if (quit) {
+            // Do no more processing if the application is already trying
+            // to exit.
+            return;
+        }
 
-            // Screen resize
-            if (event instanceof TResizeEvent) {
-                TResizeEvent resize = (TResizeEvent) event;
-                getScreen().setDimensions(resize.getWidth(),
-                    resize.getHeight());
-                desktopBottom = getScreen().getHeight() - 1;
-                repaint = true;
-                mouseX = 0;
-                mouseY = 0;
-                continue;
-            }
+        // Special application-wide events -------------------------------
 
-            // Peek at the mouse position
-            if (event instanceof TMouseEvent) {
-                TMouseEvent mouse = (TMouseEvent) event;
-                if ((mouseX != mouse.getX()) || (mouseY != mouse.getY())) {
-                    mouseX = mouse.getX();
-                    mouseY = mouse.getY();
-                    drawMouse();
-                }
+        // Abort everything
+        if (event instanceof TCommandEvent) {
+            TCommandEvent command = (TCommandEvent) event;
+            if (command.getCmd().equals(cmAbort)) {
+                quit = true;
+                return;
             }
+        }
 
-            // TODO: change to two separate threads
-            primaryHandleEvent(event);
-
-            /*
-
-            // Put into the main queue
-            addEvent(event);
-
-            // Have one of the two consumer Fibers peel the events off
-            // the queue.
-            if (secondaryEventFiber !is null) {
-                assert(secondaryEventFiber.state == Fiber.State.HOLD);
-
-                // Wake up the secondary handler for these events
-                secondaryEventFiber.call();
-            } else {
-                assert(primaryEventFiber.state == Fiber.State.HOLD);
+        // Screen resize
+        if (event instanceof TResizeEvent) {
+            TResizeEvent resize = (TResizeEvent) event;
+            getScreen().setDimensions(resize.getWidth(),
+                resize.getHeight());
+            desktopBottom = getScreen().getHeight() - 1;
+            repaint = true;
+            mouseX = 0;
+            mouseY = 0;
+            return;
+        }
 
-                // Wake up the primary handler for these events
-                primaryEventFiber.call();
+        // Peek at the mouse position
+        if (event instanceof TMouseEvent) {
+            TMouseEvent mouse = (TMouseEvent) event;
+            if ((mouseX != mouse.getX()) || (mouseY != mouse.getY())) {
+                mouseX = mouse.getX();
+                mouseY = mouse.getY();
+                drawMouse();
             }
-             */
+        }
 
-        } // for (TInputEvent event: events)
+         // Put into the main queue
+        synchronized (drainEventQueue) {
+            drainEventQueue.add(event);
+        }
 
+        // Wake all threads: primary thread will either be consuming events
+        // again or waiting in yield(), and secondary thread will either not
+        // exist or consuming events.
+        synchronized (this) {
+            this.notifyAll();
+        }
     }
 
     /**
@@ -511,15 +637,16 @@ public class TApplication {
             return;
         }
 
-        /*
-         TODO
-
         if (event instanceof TKeypressEvent) {
             TKeypressEvent keypress = (TKeypressEvent) event;
+
             // See if this key matches an accelerator, and if so dispatch the
             // menu event.
             TKeypress keypressLowercase = keypress.getKey().toLowerCase();
-            TMenuItem item = accelerators.get(keypressLowercase);
+            TMenuItem item = null;
+            synchronized (accelerators) {
+                item = accelerators.get(keypressLowercase);
+            }
             if (item != null) {
                 // Let the menu item dispatch
                 item.dispatch();
@@ -531,7 +658,6 @@ public class TApplication {
                 }
             }
         }
-         */
 
         if (event instanceof TCommandEvent) {
             if (onCommand((TCommandEvent) event)) {
@@ -571,35 +697,65 @@ public class TApplication {
      * @see #primaryHandleEvent(TInputEvent event)
      */
     private void secondaryHandleEvent(final TInputEvent event) {
-        // TODO
+        secondaryEventReceiver.handleEvent(event);
+    }
+
+    /**
+     * Enable a widget to override the primary event thread.
+     *
+     * @param widget widget that will receive events
+     */
+    public final void enableSecondaryEventReceiver(final TWidget widget) {
+        assert (secondaryEventReceiver == null);
+        assert (secondaryEventHandler == null);
+        assert (widget instanceof TMessageBox);
+        secondaryEventReceiver = widget;
+        secondaryEventHandler = new WidgetEventHandler(this, false);
+        (new Thread(secondaryEventHandler)).start();
+
+        // Refresh
+        repaint = true;
+    }
+
+    /**
+     * Yield to the secondary thread.
+     */
+    public final void yield() {
+        assert (secondaryEventReceiver != null);
+        while (secondaryEventReceiver != null) {
+            synchronized (this) {
+                try {
+                    this.wait();
+                } catch (InterruptedException e) {
+                    // SQUASH
+                }
+            }
+        }
     }
 
     /**
      * Do stuff when there is no user input.
      */
     private void doIdle() {
-        /*
-         TODO
         // Now run any timers that have timed out
-        auto now = Clock.currTime;
-        TTimer [] keepTimers;
-        foreach (t; timers) {
-            if (t.nextTick < now) {
-                t.tick();
-                if (t.recurring == true) {
-                    keepTimers ~= t;
+        Date now = new Date();
+        List<TTimer> keepTimers = new LinkedList<TTimer>();
+        for (TTimer timer: timers) {
+            if (timer.getNextTick().getTime() < now.getTime()) {
+                timer.tick();
+                if (timer.recurring) {
+                    keepTimers.add(timer);
                 }
             } else {
-                keepTimers ~= t;
+                keepTimers.add(timer);
             }
         }
         timers = keepTimers;
 
         // Call onIdle's
-        foreach (w; windows) {
-            w.onIdle();
+        for (TWindow window: windows) {
+            window.onIdle();
         }
-         */
     }
 
     /**
@@ -609,24 +765,20 @@ public class TApplication {
      * @return number of milliseconds between now and the next timer event
      */
     protected int getSleepTime(final int timeout) {
-        /*
-        auto now = Clock.currTime;
-        auto sleepTime = dur!("msecs")(timeout);
-        foreach (t; timers) {
-            if (t.nextTick < now) {
+        Date now = new Date();
+        long sleepTime = timeout;
+        for (TTimer timer: timers) {
+            if (timer.getNextTick().getTime() < now.getTime()) {
                 return 0;
             }
-            if ((t.nextTick > now) &&
-                ((t.nextTick - now) < sleepTime)
+            if ((timer.getNextTick().getTime() > now.getTime())
+                && ((timer.getNextTick().getTime() - now.getTime()) < sleepTime)
             ) {
-                sleepTime = t.nextTick - now;
+                sleepTime = timer.getNextTick().getTime() - now.getTime();
             }
         }
-        assert(sleepTime.total!("msecs")() >= 0);
-        return cast(uint)sleepTime.total!("msecs")();
-         */
-        // TODO: fix timers.  Until then, come back after 250 millis.
-        return 250;
+        assert (sleepTime >= 0);
+        return (int)sleepTime;
     }
 
     /**
@@ -660,32 +812,20 @@ public class TApplication {
         // Refresh screen
         repaint = true;
 
-        /*
-         TODO
-
-
         // Check if we are closing a TMessageBox or similar
-        if (secondaryEventReceiver !is null) {
-            assert(secondaryEventFiber !is null);
+        if (secondaryEventReceiver != null) {
+            assert (secondaryEventHandler != null);
 
             // Do not send events to the secondaryEventReceiver anymore, the
             // window is closed.
             secondaryEventReceiver = null;
 
-            // Special case: if this is called while executing on a
-            // secondaryEventFiber, call it so that widgetEventHandler() can
-            // terminate.
-            if (secondaryEventFiber.state == Fiber.State.HOLD) {
-                secondaryEventFiber.call();
-            }
-            secondaryEventFiber = null;
-
-            // Unfreeze the logic in handleEvent()
-            if (primaryEventFiber.state == Fiber.State.HOLD) {
-                primaryEventFiber.call();
+            // Wake all threads: primary thread will be consuming events
+            // again, and secondary thread will exit.
+            synchronized (this) {
+                this.notifyAll();
             }
         }
-         */
     }
 
     /**
@@ -976,23 +1116,24 @@ public class TApplication {
      * @return if true, this event was consumed
      */
     protected boolean onCommand(final TCommandEvent command) {
-        /*
-         TODO
         // Default: handle cmExit
         if (command.equals(cmExit)) {
             if (messageBox("Confirmation", "Exit application?",
-                    TMessageBox.Type.YESNO).result == TMessageBox.Result.YES) {
+                    TMessageBox.Type.YESNO).getResult() == TMessageBox.Result.YES) {
                 quit = true;
             }
             repaint = true;
             return true;
         }
 
+        /*
+         TODO
         if (command.equals(cmShell)) {
             openTerminal(0, 0, TWindow.Flag.RESIZABLE);
             repaint = true;
             return true;
         }
+         */
 
         if (command.equals(cmTile)) {
             tileWindows();
@@ -1009,7 +1150,7 @@ public class TApplication {
             repaint = true;
             return true;
         }
-         */
+
         return false;
     }
 
@@ -1022,12 +1163,10 @@ public class TApplication {
      */
     protected boolean onMenu(final TMenuEvent menu) {
 
-        /*
-         TODO
         // Default: handle MID_EXIT
-        if (menu.id == TMenu.MID_EXIT) {
+        if (menu.getId() == TMenu.MID_EXIT) {
             if (messageBox("Confirmation", "Exit application?",
-                    TMessageBox.Type.YESNO).result == TMessageBox.Result.YES) {
+                    TMessageBox.Type.YESNO).getResult() == TMessageBox.Result.YES) {
                 quit = true;
             }
             // System.err.printf("onMenu MID_EXIT result: quit = %s\n", quit);
@@ -1035,28 +1174,30 @@ public class TApplication {
             return true;
         }
 
+        /*
+         TODO
         if (menu.id == TMenu.MID_SHELL) {
             openTerminal(0, 0, TWindow.Flag.RESIZABLE);
             repaint = true;
             return true;
         }
+         */
 
-        if (menu.id == TMenu.MID_TILE) {
+        if (menu.getId() == TMenu.MID_TILE) {
             tileWindows();
             repaint = true;
             return true;
         }
-        if (menu.id == TMenu.MID_CASCADE) {
+        if (menu.getId() == TMenu.MID_CASCADE) {
             cascadeWindows();
             repaint = true;
             return true;
         }
-        if (menu.id == TMenu.MID_CLOSE_ALL) {
+        if (menu.getId() == TMenu.MID_CLOSE_ALL) {
             closeAllWindows();
             repaint = true;
             return true;
         }
-        */
         return false;
     }
 
@@ -1101,11 +1242,13 @@ public class TApplication {
      */
     public final void addAccelerator(final TMenuItem item,
         final TKeypress keypress) {
-        /*
-         TODO
-        assert((keypress in accelerators) is null);
-        accelerators[keypress] = item;
-         */
+
+        // System.err.printf("addAccelerator: key %s item %s\n", keypress, item);
+
+        synchronized (accelerators) {
+            assert (accelerators.get(keypress) == null);
+            accelerators.put(keypress, item);
+        }
     }
 
     /**
@@ -1125,10 +1268,9 @@ public class TApplication {
      * @param event new event to add to the queue
      */
     public final void addMenuEvent(final TInputEvent event) {
-        /*
-         TODO - synchronize correctly
-        eventQueue ~= event;
-         */
+        synchronized (fillEventQueue) {
+            fillEventQueue.add(event);
+        }
         closeMenu();
     }
 
@@ -1141,4 +1283,250 @@ public class TApplication {
         subMenus.add(menu);
     }
 
+    /**
+     * Convenience function to add a top-level menu.
+     *
+     * @param title menu title
+     * @return the new menu
+     */
+    public final TMenu addMenu(final String title) {
+        int x = 0;
+        int y = 0;
+        TMenu menu = new TMenu(this, x, y, title);
+        menus.add(menu);
+        recomputeMenuX();
+        return menu;
+    }
+
+    /**
+     * Convenience function to add a default "File" menu.
+     *
+     * @return the new menu
+     */
+    public final TMenu addFileMenu() {
+        TMenu fileMenu = addMenu("&File");
+        fileMenu.addDefaultItem(TMenu.MID_OPEN_FILE);
+        fileMenu.addSeparator();
+        fileMenu.addDefaultItem(TMenu.MID_SHELL);
+        fileMenu.addDefaultItem(TMenu.MID_EXIT);
+        return fileMenu;
+    }
+
+    /**
+     * Convenience function to add a default "Edit" menu.
+     *
+     * @return the new menu
+     */
+    public final TMenu addEditMenu() {
+        TMenu editMenu = addMenu("&Edit");
+        editMenu.addDefaultItem(TMenu.MID_CUT);
+        editMenu.addDefaultItem(TMenu.MID_COPY);
+        editMenu.addDefaultItem(TMenu.MID_PASTE);
+        editMenu.addDefaultItem(TMenu.MID_CLEAR);
+        return editMenu;
+    }
+
+    /**
+     * Convenience function to add a default "Window" menu.
+     *
+     * @return the new menu
+     */
+    public final TMenu addWindowMenu() {
+        TMenu windowMenu = addMenu("&Window");
+        windowMenu.addDefaultItem(TMenu.MID_TILE);
+        windowMenu.addDefaultItem(TMenu.MID_CASCADE);
+        windowMenu.addDefaultItem(TMenu.MID_CLOSE_ALL);
+        windowMenu.addSeparator();
+        windowMenu.addDefaultItem(TMenu.MID_WINDOW_MOVE);
+        windowMenu.addDefaultItem(TMenu.MID_WINDOW_ZOOM);
+        windowMenu.addDefaultItem(TMenu.MID_WINDOW_NEXT);
+        windowMenu.addDefaultItem(TMenu.MID_WINDOW_PREVIOUS);
+        windowMenu.addDefaultItem(TMenu.MID_WINDOW_CLOSE);
+        return windowMenu;
+    }
+
+    /**
+     * Close all open windows.
+     */
+    private void closeAllWindows() {
+        // Don't do anything if we are in the menu
+        if (activeMenu != null) {
+            return;
+        }
+        for (TWindow window: windows) {
+            closeWindow(window);
+        }
+    }
+
+    /**
+     * Re-layout the open windows as non-overlapping tiles.  This produces
+     * almost the same results as Turbo Pascal 7.0's IDE.
+     */
+    private void tileWindows() {
+        // Don't do anything if we are in the menu
+        if (activeMenu != null) {
+            return;
+        }
+        int z = windows.size();
+        if (z == 0) {
+            return;
+        }
+        int a = 0;
+        int b = 0;
+        a = (int)(Math.sqrt(z));
+        int c = 0;
+        while (c < a) {
+            b = (z - c) / a;
+            if (((a * b) + c) == z) {
+                break;
+            }
+            c++;
+        }
+        assert (a > 0);
+        assert (b > 0);
+        assert (c < a);
+        int newWidth = (getScreen().getWidth() / a);
+        int newHeight1 = ((getScreen().getHeight() - 1) / b);
+        int newHeight2 = ((getScreen().getHeight() - 1) / (b + c));
+        // System.err.printf("Z %s a %s b %s c %s newWidth %s newHeight1 %s newHeight2 %s",
+        //     z, a, b, c, newWidth, newHeight1, newHeight2);
+
+        List<TWindow> sorted = new LinkedList<TWindow>(windows);
+        Collections.sort(sorted);
+        Collections.reverse(sorted);
+        for (int i = 0; i < sorted.size(); i++) {
+            int logicalX = i / b;
+            int logicalY = i % b;
+            if (i >= ((a - 1) * b)) {
+                logicalX = a - 1;
+                logicalY = i - ((a - 1) * b);
+            }
+
+            TWindow w = sorted.get(i);
+            w.setX(logicalX * newWidth);
+            w.setWidth(newWidth);
+            if (i >= ((a - 1) * b)) {
+                w.setY((logicalY * newHeight2) + 1);
+                w.setHeight(newHeight2);
+            } else {
+                w.setY((logicalY * newHeight1) + 1);
+                w.setHeight(newHeight1);
+            }
+        }
+    }
+
+    /**
+     * Re-layout the open windows as overlapping cascaded windows.
+     */
+    private void cascadeWindows() {
+        // Don't do anything if we are in the menu
+        if (activeMenu != null) {
+            return;
+        }
+        int x = 0;
+        int y = 1;
+        List<TWindow> sorted = new LinkedList<TWindow>(windows);
+        Collections.sort(sorted);
+        Collections.reverse(sorted);
+        for (TWindow window: sorted) {
+            window.setX(x);
+            window.setY(y);
+            x++;
+            y++;
+            if (x > getScreen().getWidth()) {
+                x = 0;
+            }
+            if (y >= getScreen().getHeight()) {
+                y = 1;
+            }
+        }
+    }
+
+    /**
+     * Convenience function to add a timer.
+     *
+     * @param duration number of milliseconds to wait between ticks
+     * @param recurring if true, re-schedule this timer after every tick
+     * @param action function to call when button is pressed
+     * @return the timer
+     */
+    public final TTimer addTimer(final long duration, final boolean recurring,
+        final TAction action) {
+
+        TTimer timer = new TTimer(duration, recurring, action);
+        synchronized (timers) {
+            timers.add(timer);
+        }
+        return timer;
+    }
+
+    /**
+     * Convenience function to remove a timer.
+     *
+     * @param timer timer to remove
+     */
+    public final void removeTimer(final TTimer timer) {
+        synchronized (timers) {
+            timers.remove(timer);
+        }
+    }
+
+    /**
+     * Convenience function to spawn a message box.
+     *
+     * @param title window title, will be centered along the top border
+     * @param caption message to display.  Use embedded newlines to get a
+     * multi-line box.
+     * @return the new message box
+     */
+    public final TMessageBox messageBox(final String title,
+        final String caption) {
+
+        return new TMessageBox(this, title, caption, TMessageBox.Type.OK);
+    }
+
+    /**
+     * Convenience function to spawn a message box.
+     *
+     * @param title window title, will be centered along the top border
+     * @param caption message to display.  Use embedded newlines to get a
+     * multi-line box.
+     * @param type one of the TMessageBox.Type constants.  Default is
+     * Type.OK.
+     * @return the new message box
+     */
+    public final TMessageBox messageBox(final String title,
+        final String caption, final TMessageBox.Type type) {
+
+        return new TMessageBox(this, title, caption, type);
+    }
+
+    /**
+     * Convenience function to spawn an input box.
+     *
+     * @param title window title, will be centered along the top border
+     * @param caption message to display.  Use embedded newlines to get a
+     * multi-line box.
+     * @return the new input box
+     */
+    public final TInputBox inputBox(final String title, final String caption) {
+
+        return new TInputBox(this, title, caption);
+    }
+
+    /**
+     * Convenience function to spawn an input box.
+     *
+     * @param title window title, will be centered along the top border
+     * @param caption message to display.  Use embedded newlines to get a
+     * multi-line box.
+     * @param text initial text to seed the field with
+     * @return the new input box
+     */
+    public final TInputBox inputBox(final String title, final String caption,
+        final String text) {
+
+        return new TInputBox(this, title, caption, text);
+    }
+
 }