/*
 * Copyright (c) 1997, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.  Oracle designates this
 * particular file as subject to the "Classpath" exception as provided
 * by Oracle in the LICENSE file that accompanied this code.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 */
package javax.swing;


import java.awt.*;
import java.awt.event.*;
import java.awt.image.VolatileImage;
import java.security.AccessControlContext;
import java.security.AccessController;
import java.security.PrivilegedAction;
import java.util.*;
import java.util.concurrent.atomic.AtomicInteger;
import java.applet.*;

import jdk.internal.misc.JavaSecurityAccess;
import jdk.internal.misc.SharedSecrets;
import sun.awt.AWTAccessor;
import sun.awt.AppContext;
import sun.awt.DisplayChangedListener;
import sun.awt.SunToolkit;
import sun.java2d.SunGraphicsEnvironment;
import sun.security.action.GetPropertyAction;

import com.sun.java.swing.SwingUtilities3;
import java.awt.geom.AffineTransform;
import sun.java2d.SunGraphics2D;
import sun.java2d.pipe.Region;
import sun.swing.SwingAccessor;
import sun.swing.SwingUtilities2;
import sun.swing.SwingUtilities2.RepaintListener;

This class manages repaint requests, allowing the number
of repaints to be minimized, for example by collapsing multiple
requests into a single repaint for members of a component tree.

As of 1.6 RepaintManager handles repaint requests
for Swing's top level components (JApplet,
JWindow, JFrame and JDialog).
Any calls to repaint on one of these will call into the
appropriate addDirtyRegion method.
Author:
Arnaud Weber
Since:
1.2/**
 * This class manages repaint requests, allowing the number
 * of repaints to be minimized, for example by collapsing multiple
 * requests into a single repaint for members of a component tree.
 * <p>
 * As of 1.6 <code>RepaintManager</code> handles repaint requests
 * for Swing's top level components (<code>JApplet</code>,
 * <code>JWindow</code>, <code>JFrame</code> and <code>JDialog</code>).
 * Any calls to <code>repaint</code> on one of these will call into the
 * appropriate <code>addDirtyRegion</code> method.
 *
 * @author Arnaud Weber
 * @since 1.2
 */
public class RepaintManager
{
    
Whether or not the RepaintManager should handle paint requests
for top levels.
/**
     * Whether or not the RepaintManager should handle paint requests
     * for top levels.
     */
    static final boolean HANDLE_TOP_LEVEL_PAINT;

    private static final short BUFFER_STRATEGY_NOT_SPECIFIED = 0;
    private static final short BUFFER_STRATEGY_SPECIFIED_ON = 1;
    private static final short BUFFER_STRATEGY_SPECIFIED_OFF = 2;

    private static final short BUFFER_STRATEGY_TYPE;

    
Maps from GraphicsConfiguration to VolatileImage.
/**
     * Maps from GraphicsConfiguration to VolatileImage.
     */
    private Map<GraphicsConfiguration,VolatileImage> volatileMap = new
                        HashMap<GraphicsConfiguration,VolatileImage>(1);

    //
    // As of 1.6 Swing handles scheduling of paint events from native code.
    // That is, SwingPaintEventDispatcher is invoked on the toolkit thread,
    // which in turn invokes nativeAddDirtyRegion.  Because this is invoked
    // from the native thread we can not invoke any public methods and so
    // we introduce these added maps.  So, any time nativeAddDirtyRegion is
    // invoked the region is added to hwDirtyComponents and a work request
    // is scheduled.  When the work request is processed all entries in
    // this map are pushed to the real map (dirtyComponents) and then
    // painted with the rest of the components.
    //
    private Map<Container,Rectangle> hwDirtyComponents;

    private Map<Component,Rectangle> dirtyComponents;
    private Map<Component,Rectangle> tmpDirtyComponents;
    private java.util.List<Component> invalidComponents;

    // List of Runnables that need to be processed before painting from AWT.
    private java.util.List<Runnable> runnableList;

    boolean   doubleBufferingEnabled = true;

    private Dimension doubleBufferMaxSize;

    private boolean isCustomMaxBufferSizeSet = false;

    // Support for both the standard and volatile offscreen buffers exists to
    // provide backwards compatibility for the [rare] programs which may be
    // calling getOffScreenBuffer() and not expecting to get a VolatileImage.
    // Swing internally is migrating to use *only* the volatile image buffer.

    // Support for standard offscreen buffer
    //
    DoubleBufferInfo standardDoubleBuffer;

    
Object responsible for hanlding core paint functionality.
/**
     * Object responsible for hanlding core paint functionality.
     */
    private PaintManager paintManager;

    private static final Object repaintManagerKey = RepaintManager.class;

    // Whether or not a VolatileImage should be used for double-buffered painting
    static boolean volatileImageBufferEnabled = true;
    
Type of VolatileImage which should be used for double-buffered
painting.
/**
     * Type of VolatileImage which should be used for double-buffered
     * painting.
     */
    private static final int volatileBufferType;
    
Value of the system property awt.nativeDoubleBuffering.
/**
     * Value of the system property awt.nativeDoubleBuffering.
     */
    private static boolean nativeDoubleBuffering;

    // The maximum number of times Swing will attempt to use the VolatileImage
    // buffer during a paint operation.
    private static final int VOLATILE_LOOP_MAX = 2;

    
Number of beginPaint that have been invoked.
/**
     * Number of <code>beginPaint</code> that have been invoked.
     */
    private int paintDepth = 0;

    
Type of buffer strategy to use.  Will be one of the BUFFER_STRATEGY_
constants.
/**
     * Type of buffer strategy to use.  Will be one of the BUFFER_STRATEGY_
     * constants.
     */
    private short bufferStrategyType;

    //
    // BufferStrategyPaintManager has the unique characteristic that it
    // must deal with the buffer being lost while painting to it.  For
    // example, if we paint a component and show it and the buffer has
    // become lost we must repaint the whole window.  To deal with that
    // the PaintManager calls into repaintRoot, and if we're still in
    // the process of painting the repaintRoot field is set to the JRootPane
    // and after the current JComponent.paintImmediately call finishes
    // paintImmediately will be invoked on the repaintRoot.  In this
    // way we don't try to show garbage to the screen.
    //
    
True if we're in the process of painting the dirty regions.  This is
set to true in paintDirtyRegions.
/**
     * True if we're in the process of painting the dirty regions.  This is
     * set to true in <code>paintDirtyRegions</code>.
     */
    private boolean painting;
    
If the PaintManager calls into repaintRoot during painting this field
will be set to the root.
/**
     * If the PaintManager calls into repaintRoot during painting this field
     * will be set to the root.
     */
    private JComponent repaintRoot;

    
The Thread that has initiated painting.  If null it
indicates painting is not currently in progress.
/**
     * The Thread that has initiated painting.  If null it
     * indicates painting is not currently in progress.
     */
    private Thread paintThread;

    
Runnable used to process all repaint/revalidate requests.
/**
     * Runnable used to process all repaint/revalidate requests.
     */
    private final ProcessingRunnable processingRunnable;

    private static final JavaSecurityAccess javaSecurityAccess =
            SharedSecrets.getJavaSecurityAccess();

    
Listener installed to detect display changes. When display changes,
schedules a callback to notify all RepaintManagers of the display
changes.
/**
     * Listener installed to detect display changes. When display changes,
     * schedules a callback to notify all RepaintManagers of the display
     * changes.
     */
    private static final DisplayChangedListener displayChangedHandler =
            new DisplayChangedHandler();

    static {
        SwingAccessor.setRepaintManagerAccessor(new SwingAccessor.RepaintManagerAccessor() {
            @Override
            public void addRepaintListener(RepaintManager rm, RepaintListener l) {
                rm.addRepaintListener(l);
            }
            @Override
            public void removeRepaintListener(RepaintManager rm, RepaintListener l) {
                rm.removeRepaintListener(l);
            }
        });

        volatileImageBufferEnabled = "true".equals(AccessController.
                doPrivileged(new GetPropertyAction(
                "swing.volatileImageBufferEnabled", "true")));
        boolean headless = GraphicsEnvironment.isHeadless();
        if (volatileImageBufferEnabled && headless) {
            volatileImageBufferEnabled = false;
        }
        nativeDoubleBuffering = "true".equals(AccessController.doPrivileged(
                    new GetPropertyAction("awt.nativeDoubleBuffering")));
        String bs = AccessController.doPrivileged(
                          new GetPropertyAction("swing.bufferPerWindow"));
        if (headless) {
            BUFFER_STRATEGY_TYPE = BUFFER_STRATEGY_SPECIFIED_OFF;
        }
        else if (bs == null) {
            BUFFER_STRATEGY_TYPE = BUFFER_STRATEGY_NOT_SPECIFIED;
        }
        else if ("true".equals(bs)) {
            BUFFER_STRATEGY_TYPE = BUFFER_STRATEGY_SPECIFIED_ON;
        }
        else {
            BUFFER_STRATEGY_TYPE = BUFFER_STRATEGY_SPECIFIED_OFF;
        }
        HANDLE_TOP_LEVEL_PAINT = "true".equals(AccessController.doPrivileged(
               new GetPropertyAction("swing.handleTopLevelPaint", "true")));
        GraphicsEnvironment ge = GraphicsEnvironment.
                getLocalGraphicsEnvironment();
        if (ge instanceof SunGraphicsEnvironment) {
            ((SunGraphicsEnvironment) ge).addDisplayChangedListener(
                    displayChangedHandler);
        }
        Toolkit tk = Toolkit.getDefaultToolkit();
        if ((tk instanceof SunToolkit)
                && ((SunToolkit) tk).isSwingBackbufferTranslucencySupported()) {
            volatileBufferType = Transparency.TRANSLUCENT;
        } else {
            volatileBufferType = Transparency.OPAQUE;
        }
    }

    
Return the RepaintManager for the calling thread given a Component.
Params:
c – a Component -- unused in the default implementation, but could
         be used by an overridden version to return a different RepaintManager
         depending on the Component
Returns:
the RepaintManager object/**
     * Return the RepaintManager for the calling thread given a Component.
     *
     * @param c a Component -- unused in the default implementation, but could
     *          be used by an overridden version to return a different RepaintManager
     *          depending on the Component
     * @return the RepaintManager object
     */
    public static RepaintManager currentManager(Component c) {
        // Note: DisplayChangedRunnable passes in null as the component, so if
        // component is ever used to determine the current
        // RepaintManager, DisplayChangedRunnable will need to be modified
        // accordingly.
        return currentManager(AppContext.getAppContext());
    }

    
Returns the RepaintManager for the specified AppContext.  If
a RepaintManager has not been created for the specified
AppContext this will return null.
/**
     * Returns the RepaintManager for the specified AppContext.  If
     * a RepaintManager has not been created for the specified
     * AppContext this will return null.
     */
    static RepaintManager currentManager(AppContext appContext) {
        RepaintManager rm = (RepaintManager)appContext.get(repaintManagerKey);
        if (rm == null) {
            rm = new RepaintManager(BUFFER_STRATEGY_TYPE);
            appContext.put(repaintManagerKey, rm);
        }
        return rm;
    }

    
Return the RepaintManager for the calling thread given a JComponent.
 Note: This method exists for backward binary compatibility with earlier versions of the Swing library. It simply returns the result returned by currentManager(Component). 
Params:
c – a JComponent -- unused
Returns:
the RepaintManager object/**
     * Return the RepaintManager for the calling thread given a JComponent.
     * <p>
    * Note: This method exists for backward binary compatibility with earlier
     * versions of the Swing library. It simply returns the result returned by
     * {@link #currentManager(Component)}.
     *
     * @param c a JComponent -- unused
     * @return the RepaintManager object
     */
    public static RepaintManager currentManager(JComponent c) {
        return currentManager((Component)c);
    }


    
Set the RepaintManager that should be used for the calling
thread. aRepaintManager will become the current RepaintManager
for the calling thread's thread group.
Params:
aRepaintManager –  the RepaintManager object to use/**
     * Set the RepaintManager that should be used for the calling
     * thread. <b>aRepaintManager</b> will become the current RepaintManager
     * for the calling thread's thread group.
     * @param aRepaintManager  the RepaintManager object to use
     */
    public static void setCurrentManager(RepaintManager aRepaintManager) {
        if (aRepaintManager != null) {
            SwingUtilities.appContextPut(repaintManagerKey, aRepaintManager);
        } else {
            SwingUtilities.appContextRemove(repaintManagerKey);
        }
    }

    
Create a new RepaintManager instance. You rarely call this constructor.
directly. To get the default RepaintManager, use
RepaintManager.currentManager(JComponent) (normally "this").
/**
     * Create a new RepaintManager instance. You rarely call this constructor.
     * directly. To get the default RepaintManager, use
     * RepaintManager.currentManager(JComponent) (normally "this").
     */
    public RepaintManager() {
        // Because we can't know what a subclass is doing with the
        // volatile image we immediately punt in subclasses.  If this
        // poses a problem we'll need a more sophisticated detection algorithm,
        // or API.
        this(BUFFER_STRATEGY_SPECIFIED_OFF);
    }

    private RepaintManager(short bufferStrategyType) {
        // If native doublebuffering is being used, do NOT use
        // Swing doublebuffering.
        doubleBufferingEnabled = !nativeDoubleBuffering;
        synchronized(this) {
            dirtyComponents = new IdentityHashMap<Component,Rectangle>();
            tmpDirtyComponents = new IdentityHashMap<Component,Rectangle>();
            this.bufferStrategyType = bufferStrategyType;
            hwDirtyComponents = new IdentityHashMap<Container,Rectangle>();
        }
        processingRunnable = new ProcessingRunnable();
    }

    private void displayChanged() {
        if (isCustomMaxBufferSizeSet) {
            clearImages();
        } else {
            // Reset buffer maximum size to get valid size from updated graphics
            // environment in getDoubleBufferMaximumSize()
            setDoubleBufferMaximumSize(null);
        }
    }

    
Mark the component as in need of layout and queue a runnable
for the event dispatching thread that will validate the components
first isValidateRoot() ancestor.
Params:
invalidComponent – a component
See Also:
JComponent.isValidateRoot
removeInvalidComponent/**
     * Mark the component as in need of layout and queue a runnable
     * for the event dispatching thread that will validate the components
     * first isValidateRoot() ancestor.
     *
     * @param invalidComponent a component
     * @see JComponent#isValidateRoot
     * @see #removeInvalidComponent
     */
    public synchronized void addInvalidComponent(JComponent invalidComponent)
    {
        RepaintManager delegate = getDelegate(invalidComponent);
        if (delegate != null) {
            delegate.addInvalidComponent(invalidComponent);
            return;
        }
        Component validateRoot =
            SwingUtilities.getValidateRoot(invalidComponent, true);

        if (validateRoot == null) {
            return;
        }

        /* Lazily create the invalidateComponents vector and add the
         * validateRoot if it's not there already.  If this validateRoot
         * is already in the vector, we're done.
         */
        if (invalidComponents == null) {
            invalidComponents = new ArrayList<Component>();
        }
        else {
            int n = invalidComponents.size();
            for(int i = 0; i < n; i++) {
                if(validateRoot == invalidComponents.get(i)) {
                    return;
                }
            }
        }
        invalidComponents.add(validateRoot);

        // Queue a Runnable to invoke paintDirtyRegions and
        // validateInvalidComponents.
        scheduleProcessingRunnable(SunToolkit.targetToAppContext(invalidComponent));
    }


    
Remove a component from the list of invalid components.
Params:
component – a component
See Also:
addInvalidComponent/**
     * Remove a component from the list of invalid components.
     *
     * @param component a component
     * @see #addInvalidComponent
     */
    public synchronized void removeInvalidComponent(JComponent component) {
        RepaintManager delegate = getDelegate(component);
        if (delegate != null) {
            delegate.removeInvalidComponent(component);
            return;
        }
        if(invalidComponents != null) {
            int index = invalidComponents.indexOf(component);
            if(index != -1) {
                invalidComponents.remove(index);
            }
        }
    }


    
Add a component in the list of components that should be refreshed.
If c already has a dirty region, the rectangle (x,y,w,h)
will be unioned with the region that should be redrawn.
See Also:
repaint.repaint/**
     * Add a component in the list of components that should be refreshed.
     * If <i>c</i> already has a dirty region, the rectangle <i>(x,y,w,h)</i>
     * will be unioned with the region that should be redrawn.
     *
     * @see JComponent#repaint
     */
    @SuppressWarnings("deprecation")
    private void addDirtyRegion0(Container c, int x, int y, int w, int h) {
        /* Special cases we don't have to bother with.
         */
        if ((w <= 0) || (h <= 0) || (c == null)) {
            return;
        }

        if ((c.getWidth() <= 0) || (c.getHeight() <= 0)) {
            return;
        }

        if (extendDirtyRegion(c, x, y, w, h)) {
            // Component was already marked as dirty, region has been
            // extended, no need to continue.
            return;
        }

        /* Make sure that c and all it ancestors (up to an Applet or
         * Window) are visible.  This loop has the same effect as
         * checking c.isShowing() (and note that it's still possible
         * that c is completely obscured by an opaque ancestor in
         * the specified rectangle).
         */
        Component root = null;

        // Note: We can't synchronize around this, Frame.getExtendedState
        // is synchronized so that if we were to synchronize around this
        // it could lead to the possibility of getting locks out
        // of order and deadlocking.
        for (Container p = c; p != null; p = p.getParent()) {
            if (!p.isVisible() || !p.isDisplayable()) {
                return;
            }
            if ((p instanceof Window) || (p instanceof Applet)) {
                // Iconified frames are still visible!
                if (p instanceof Frame &&
                        (((Frame)p).getExtendedState() & Frame.ICONIFIED) ==
                                    Frame.ICONIFIED) {
                    return;
                }
                root = p;
                break;
            }
        }

        if (root == null) return;

        synchronized(this) {
            if (extendDirtyRegion(c, x, y, w, h)) {
                // In between last check and this check another thread
                // queued up runnable, can bail here.
                return;
            }
            dirtyComponents.put(c, new Rectangle(x, y, w, h));
        }

        // Queue a Runnable to invoke paintDirtyRegions and
        // validateInvalidComponents.
        scheduleProcessingRunnable(SunToolkit.targetToAppContext(c));
    }

    
Add a component in the list of components that should be refreshed.
If c already has a dirty region, the rectangle (x,y,w,h)
will be unioned with the region that should be redrawn.
Params:
c – Component to repaint, null results in nothing happening.
x – X coordinate of the region to repaint
y – Y coordinate of the region to repaint
w – Width of the region to repaint
h – Height of the region to repaint
See Also:
Component.repaint/**
     * Add a component in the list of components that should be refreshed.
     * If <i>c</i> already has a dirty region, the rectangle <i>(x,y,w,h)</i>
     * will be unioned with the region that should be redrawn.
     *
     * @param c Component to repaint, null results in nothing happening.
     * @param x X coordinate of the region to repaint
     * @param y Y coordinate of the region to repaint
     * @param w Width of the region to repaint
     * @param h Height of the region to repaint
     * @see JComponent#repaint
     */
    public void addDirtyRegion(JComponent c, int x, int y, int w, int h)
    {
        RepaintManager delegate = getDelegate(c);
        if (delegate != null) {
            delegate.addDirtyRegion(c, x, y, w, h);
            return;
        }
        addDirtyRegion0(c, x, y, w, h);
    }

    
Adds window to the list of Components that
need to be repainted.
Params:
window – Window to repaint, null results in nothing happening.
x – X coordinate of the region to repaint
y – Y coordinate of the region to repaint
w – Width of the region to repaint
h – Height of the region to repaint
See Also:
Component.repaint
Component.repaint
Component.repaint
Since:
1.6/**
     * Adds <code>window</code> to the list of <code>Component</code>s that
     * need to be repainted.
     *
     * @param window Window to repaint, null results in nothing happening.
     * @param x X coordinate of the region to repaint
     * @param y Y coordinate of the region to repaint
     * @param w Width of the region to repaint
     * @param h Height of the region to repaint
     * @see JFrame#repaint
     * @see JWindow#repaint
     * @see JDialog#repaint
     * @since 1.6
     */
    public void addDirtyRegion(Window window, int x, int y, int w, int h) {
        addDirtyRegion0(window, x, y, w, h);
    }

    
Adds applet to the list of Components that
need to be repainted.
Params:
applet – Applet to repaint, null results in nothing happening.
x – X coordinate of the region to repaint
y – Y coordinate of the region to repaint
w – Width of the region to repaint
h – Height of the region to repaint
See Also:
Component.repaint
Since:
1.6
Deprecated:
The Applet API is deprecated. See the
 java.applet package
documentation for further information./**
     * Adds <code>applet</code> to the list of <code>Component</code>s that
     * need to be repainted.
     *
     * @param applet Applet to repaint, null results in nothing happening.
     * @param x X coordinate of the region to repaint
     * @param y Y coordinate of the region to repaint
     * @param w Width of the region to repaint
     * @param h Height of the region to repaint
     * @see JApplet#repaint
     * @since 1.6
     *
     * @deprecated The Applet API is deprecated. See the
     * <a href="../../java/applet/package-summary.html"> java.applet package
     * documentation</a> for further information.
     */
    @Deprecated(since = "9")
    public void addDirtyRegion(Applet applet, int x, int y, int w, int h) {
        addDirtyRegion0(applet, x, y, w, h);
    }

    @SuppressWarnings("deprecation")
    void scheduleHeavyWeightPaints() {
        Map<Container,Rectangle> hws;

        synchronized(this) {
            if (hwDirtyComponents.size() == 0) {
                return;
            }
            hws = hwDirtyComponents;
            hwDirtyComponents =  new IdentityHashMap<Container,Rectangle>();
        }
        for (Container hw : hws.keySet()) {
            Rectangle dirty = hws.get(hw);
            if (hw instanceof Window) {
                addDirtyRegion((Window)hw, dirty.x, dirty.y,
                               dirty.width, dirty.height);
            }
            else if (hw instanceof Applet) {
                addDirtyRegion((Applet)hw, dirty.x, dirty.y,
                               dirty.width, dirty.height);
            }
            else { // SwingHeavyWeight
                addDirtyRegion0(hw, dirty.x, dirty.y,
                                dirty.width, dirty.height);
            }
        }
    }

    //
    // This is called from the toolkit thread when a native expose is
    // received.
    //
    void nativeAddDirtyRegion(AppContext appContext, Container c,
                              int x, int y, int w, int h) {
        if (w > 0 && h > 0) {
            synchronized(this) {
                Rectangle dirty = hwDirtyComponents.get(c);
                if (dirty == null) {
                    hwDirtyComponents.put(c, new Rectangle(x, y, w, h));
                }
                else {
                    hwDirtyComponents.put(c, SwingUtilities.computeUnion(
                                              x, y, w, h, dirty));
                }
            }
            scheduleProcessingRunnable(appContext);
        }
    }

    //
    // This is called from the toolkit thread when awt needs to run a
    // Runnable before we paint.
    //
    void nativeQueueSurfaceDataRunnable(AppContext appContext,
                                        final Component c, final Runnable r)
    {
        synchronized(this) {
            if (runnableList == null) {
                runnableList = new LinkedList<Runnable>();
            }
            runnableList.add(new Runnable() {
                public void run() {
                    AccessControlContext stack = AccessController.getContext();
                    AccessControlContext acc =
                        AWTAccessor.getComponentAccessor().getAccessControlContext(c);
                    javaSecurityAccess.doIntersectionPrivilege(new PrivilegedAction<Void>() {
                        public Void run() {
                            r.run();
                            return null;
                        }
                    }, stack, acc);
                }
            });
        }
        scheduleProcessingRunnable(appContext);
    }

    
Extends the dirty region for the specified component to include
the new region.
Returns:
false if c is not yet marked dirty./**
     * Extends the dirty region for the specified component to include
     * the new region.
     *
     * @return false if <code>c</code> is not yet marked dirty.
     */
    private synchronized boolean extendDirtyRegion(
        Component c, int x, int y, int w, int h) {
        Rectangle r = dirtyComponents.get(c);
        if (r != null) {
            // A non-null r implies c is already marked as dirty,
            // and that the parent is valid. Therefore we can
            // just union the rect and bail.
            SwingUtilities.computeUnion(x, y, w, h, r);
            return true;
        }
        return false;
    }

    
Return the current dirty region for a component.
Return an empty rectangle if the component is not
dirty.
Params:
aComponent – a component
Returns:
the region/**
     * Return the current dirty region for a component.
     * Return an empty rectangle if the component is not
     * dirty.
     *
     * @param aComponent a component
     * @return the region
     */
    public Rectangle getDirtyRegion(JComponent aComponent) {
        RepaintManager delegate = getDelegate(aComponent);
        if (delegate != null) {
            return delegate.getDirtyRegion(aComponent);
        }
        Rectangle r;
        synchronized(this) {
            r = dirtyComponents.get(aComponent);
        }
        if(r == null)
            return new Rectangle(0,0,0,0);
        else
            return new Rectangle(r);
    }

    
Mark a component completely dirty. aComponent will be
completely painted during the next paintDirtyRegions() call.
Params:
aComponent – a component/**
     * Mark a component completely dirty. <b>aComponent</b> will be
     * completely painted during the next paintDirtyRegions() call.
     *
     * @param aComponent a component
     */
    public void markCompletelyDirty(JComponent aComponent) {
        RepaintManager delegate = getDelegate(aComponent);
        if (delegate != null) {
            delegate.markCompletelyDirty(aComponent);
            return;
        }
        addDirtyRegion(aComponent,0,0,Integer.MAX_VALUE,Integer.MAX_VALUE);
    }

    
Mark a component completely clean. aComponent will not
get painted during the next paintDirtyRegions() call.
Params:
aComponent – a component/**
     * Mark a component completely clean. <b>aComponent</b> will not
     * get painted during the next paintDirtyRegions() call.
     *
     * @param aComponent a component
     */
    public void markCompletelyClean(JComponent aComponent) {
        RepaintManager delegate = getDelegate(aComponent);
        if (delegate != null) {
            delegate.markCompletelyClean(aComponent);
            return;
        }
        synchronized(this) {
                dirtyComponents.remove(aComponent);
        }
    }

    
Convenience method that returns true if aComponent will be completely
painted during the next paintDirtyRegions(). If computing dirty regions is
expensive for your component, use this method and avoid computing dirty region
if it return true.
Params:
aComponent – a component
Returns:
true if aComponent will be completely
        painted during the next paintDirtyRegions()./**
     * Convenience method that returns true if <b>aComponent</b> will be completely
     * painted during the next paintDirtyRegions(). If computing dirty regions is
     * expensive for your component, use this method and avoid computing dirty region
     * if it return true.
     *
     * @param aComponent a component
     * @return {@code true} if <b>aComponent</b> will be completely
     *         painted during the next paintDirtyRegions().
     */
    public boolean isCompletelyDirty(JComponent aComponent) {
        RepaintManager delegate = getDelegate(aComponent);
        if (delegate != null) {
            return delegate.isCompletelyDirty(aComponent);
        }
        Rectangle r;

        r = getDirtyRegion(aComponent);
        if(r.width == Integer.MAX_VALUE &&
           r.height == Integer.MAX_VALUE)
            return true;
        else
            return false;
    }


    
Validate all of the components that have been marked invalid.
See Also:
addInvalidComponent/**
     * Validate all of the components that have been marked invalid.
     * @see #addInvalidComponent
     */
    public void validateInvalidComponents() {
        final java.util.List<Component> ic;
        synchronized(this) {
            if (invalidComponents == null) {
                return;
            }
            ic = invalidComponents;
            invalidComponents = null;
        }
        int n = ic.size();
        for(int i = 0; i < n; i++) {
            final Component c = ic.get(i);
            AccessControlContext stack = AccessController.getContext();
            AccessControlContext acc =
                AWTAccessor.getComponentAccessor().getAccessControlContext(c);
            javaSecurityAccess.doIntersectionPrivilege(
                new PrivilegedAction<Void>() {
                    public Void run() {
                        c.validate();
                        return null;
                    }
                }, stack, acc);
        }
    }


    
This is invoked to process paint requests.  It's needed
for backward compatibility in so far as RepaintManager would previously
not see paint requests for top levels, so, we have to make sure
a subclass correctly paints any dirty top levels.
/**
     * This is invoked to process paint requests.  It's needed
     * for backward compatibility in so far as RepaintManager would previously
     * not see paint requests for top levels, so, we have to make sure
     * a subclass correctly paints any dirty top levels.
     */
    private void prePaintDirtyRegions() {
        Map<Component,Rectangle> dirtyComponents;
        java.util.List<Runnable> runnableList;
        synchronized(this) {
            dirtyComponents = this.dirtyComponents;
            runnableList = this.runnableList;
            this.runnableList = null;
        }
        if (runnableList != null) {
            for (Runnable runnable : runnableList) {
                runnable.run();
            }
        }
        paintDirtyRegions();
        if (dirtyComponents.size() > 0) {
            // This'll only happen if a subclass isn't correctly dealing
            // with toplevels.
            paintDirtyRegions(dirtyComponents);
        }
    }

    private void updateWindows(Map<Component,Rectangle> dirtyComponents) {
        Toolkit toolkit = Toolkit.getDefaultToolkit();
        if (!(toolkit instanceof SunToolkit &&
              ((SunToolkit)toolkit).needUpdateWindow()))
        {
            return;
        }

        Set<Window> windows = new HashSet<Window>();
        Set<Component> dirtyComps = dirtyComponents.keySet();
        for (Iterator<Component> it = dirtyComps.iterator(); it.hasNext();) {
            Component dirty = it.next();
            Window window = dirty instanceof Window ?
                (Window)dirty :
                SwingUtilities.getWindowAncestor(dirty);
            if (window != null &&
                !window.isOpaque())
            {
                windows.add(window);
            }
        }

        for (Window window : windows) {
            AWTAccessor.getWindowAccessor().updateWindow(window);
        }
    }

    boolean isPainting() {
        return painting;
    }

    
Paint all of the components that have been marked dirty.
See Also:
addDirtyRegion/**
     * Paint all of the components that have been marked dirty.
     *
     * @see #addDirtyRegion
     */
    public void paintDirtyRegions() {
        synchronized(this) {  // swap for thread safety
            Map<Component,Rectangle> tmp = tmpDirtyComponents;
            tmpDirtyComponents = dirtyComponents;
            dirtyComponents = tmp;
            dirtyComponents.clear();
        }
        paintDirtyRegions(tmpDirtyComponents);
    }

    private void paintDirtyRegions(
        final Map<Component,Rectangle> tmpDirtyComponents)
    {
        if (tmpDirtyComponents.isEmpty()) {
            return;
        }

        final java.util.List<Component> roots =
            new ArrayList<Component>(tmpDirtyComponents.size());
        for (Component dirty : tmpDirtyComponents.keySet()) {
            collectDirtyComponents(tmpDirtyComponents, dirty, roots);
        }

        final AtomicInteger count = new AtomicInteger(roots.size());
        painting = true;
        try {
            for (int j=0 ; j < count.get(); j++) {
                final int i = j;
                final Component dirtyComponent = roots.get(j);
                AccessControlContext stack = AccessController.getContext();
                AccessControlContext acc =
                    AWTAccessor.getComponentAccessor().getAccessControlContext(dirtyComponent);
                javaSecurityAccess.doIntersectionPrivilege(new PrivilegedAction<Void>() {
                    public Void run() {
                        Rectangle rect = tmpDirtyComponents.get(dirtyComponent);
                        // Sometimes when RepaintManager is changed during the painting
                        // we may get null here, see #6995769 for details
                        if (rect == null) {
                            return null;
                        }

                        int localBoundsH = dirtyComponent.getHeight();
                        int localBoundsW = dirtyComponent.getWidth();
                        SwingUtilities.computeIntersection(0,
                                                           0,
                                                           localBoundsW,
                                                           localBoundsH,
                                                           rect);
                        if (dirtyComponent instanceof JComponent) {
                            ((JComponent)dirtyComponent).paintImmediately(
                                rect.x,rect.y,rect.width, rect.height);
                        }
                        else if (dirtyComponent.isShowing()) {
                            Graphics g = JComponent.safelyGetGraphics(
                                    dirtyComponent, dirtyComponent);
                            // If the Graphics goes away, it means someone disposed of
                            // the window, don't do anything.
                            if (g != null) {
                                g.setClip(rect.x, rect.y, rect.width, rect.height);
                                try {
                                    dirtyComponent.paint(g);
                                } finally {
                                    g.dispose();
                                }
                            }
                        }
                        // If the repaintRoot has been set, service it now and
                        // remove any components that are children of repaintRoot.
                        if (repaintRoot != null) {
                            adjustRoots(repaintRoot, roots, i + 1);
                            count.set(roots.size());
                            paintManager.isRepaintingRoot = true;
                            repaintRoot.paintImmediately(0, 0, repaintRoot.getWidth(),
                                                         repaintRoot.getHeight());
                            paintManager.isRepaintingRoot = false;
                            // Only service repaintRoot once.
                            repaintRoot = null;
                        }

                        return null;
                    }
                }, stack, acc);
            }
        } finally {
            painting = false;
        }

        updateWindows(tmpDirtyComponents);

        tmpDirtyComponents.clear();
    }


    
Removes any components from roots that are children of
root.
/**
     * Removes any components from roots that are children of
     * root.
     */
    private void adjustRoots(JComponent root,
                             java.util.List<Component> roots, int index) {
        for (int i = roots.size() - 1; i >= index; i--) {
            Component c = roots.get(i);
            for(;;) {
                if (c == root || c == null || !(c instanceof JComponent)) {
                    break;
                }
                c = c.getParent();
            }
            if (c == root) {
                roots.remove(i);
            }
        }
    }

    Rectangle tmp = new Rectangle();

    void collectDirtyComponents(Map<Component,Rectangle> dirtyComponents,
                                Component dirtyComponent,
                                java.util.List<Component> roots) {
        int dx, dy, rootDx, rootDy;
        Component component, rootDirtyComponent,parent;
        Rectangle cBounds;

        // Find the highest parent which is dirty.  When we get out of this
        // rootDx and rootDy will contain the translation from the
        // rootDirtyComponent's coordinate system to the coordinates of the
        // original dirty component.  The tmp Rect is also used to compute the
        // visible portion of the dirtyRect.

        component = rootDirtyComponent = dirtyComponent;

        int x = dirtyComponent.getX();
        int y = dirtyComponent.getY();
        int w = dirtyComponent.getWidth();
        int h = dirtyComponent.getHeight();

        dx = rootDx = 0;
        dy = rootDy = 0;
        tmp.setBounds(dirtyComponents.get(dirtyComponent));

        // System.out.println("Collect dirty component for bound " + tmp +
        //                                   "component bounds is " + cBounds);;
        SwingUtilities.computeIntersection(0,0,w,h,tmp);

        if (tmp.isEmpty()) {
            // System.out.println("Empty 1");
            return;
        }

        for(;;) {
            if(!(component instanceof JComponent))
                break;

            parent = component.getParent();
            if(parent == null)
                break;

            component = parent;

            dx += x;
            dy += y;
            tmp.setLocation(tmp.x + x, tmp.y + y);

            x = component.getX();
            y = component.getY();
            w = component.getWidth();
            h = component.getHeight();
            tmp = SwingUtilities.computeIntersection(0,0,w,h,tmp);

            if (tmp.isEmpty()) {
                // System.out.println("Empty 2");
                return;
            }

            if (dirtyComponents.get(component) != null) {
                rootDirtyComponent = component;
                rootDx = dx;
                rootDy = dy;
            }
        }

        if (dirtyComponent != rootDirtyComponent) {
            Rectangle r;
            tmp.setLocation(tmp.x + rootDx - dx,
                            tmp.y + rootDy - dy);
            r = dirtyComponents.get(rootDirtyComponent);
            SwingUtilities.computeUnion(tmp.x,tmp.y,tmp.width,tmp.height,r);
        }

        // If we haven't seen this root before, then we need to add it to the
        // list of root dirty Views.

        if (!roots.contains(rootDirtyComponent))
            roots.add(rootDirtyComponent);
    }


    
Returns a string that displays and identifies this
object's properties.
Returns:
a String representation of this object/**
     * Returns a string that displays and identifies this
     * object's properties.
     *
     * @return a String representation of this object
     */
    public synchronized String toString() {
        StringBuilder sb = new StringBuilder();
        if(dirtyComponents != null)
            sb.append("" + dirtyComponents);
        return sb.toString();
    }


    
Return the offscreen buffer that should be used as a double buffer with
the component c.
By default there is a double buffer per RepaintManager.
The buffer might be smaller than (proposedWidth,proposedHeight)
This happens when the maximum double buffer size as been set for the receiving
repaint manager.
Params:
c – the component
proposedWidth – the width of the buffer
proposedHeight – the height of the buffer
Returns:
the image/**
     * Return the offscreen buffer that should be used as a double buffer with
     * the component <code>c</code>.
     * By default there is a double buffer per RepaintManager.
     * The buffer might be smaller than <code>(proposedWidth,proposedHeight)</code>
     * This happens when the maximum double buffer size as been set for the receiving
     * repaint manager.
     *
     * @param c the component
     * @param proposedWidth the width of the buffer
     * @param proposedHeight the height of the buffer
     *
     * @return the image
     */
    public Image getOffscreenBuffer(Component c,int proposedWidth,int proposedHeight) {
        RepaintManager delegate = getDelegate(c);
        if (delegate != null) {
            return delegate.getOffscreenBuffer(c, proposedWidth, proposedHeight);
        }
        return _getOffscreenBuffer(c, proposedWidth, proposedHeight);
    }

    
Return a volatile offscreen buffer that should be used as a
double buffer with the specified component c.
The image returned will be an instance of VolatileImage, or null
if a VolatileImage object could not be instantiated.
This buffer might be smaller than (proposedWidth,proposedHeight).
This happens when the maximum double buffer size has been set for this
repaint manager.
Params:
c – the component
proposedWidth – the width of the buffer
proposedHeight – the height of the buffer
See Also:
VolatileImage
Returns:
the volatile image
Since:
1.4/**
     * Return a volatile offscreen buffer that should be used as a
     * double buffer with the specified component <code>c</code>.
     * The image returned will be an instance of VolatileImage, or null
     * if a VolatileImage object could not be instantiated.
     * This buffer might be smaller than <code>(proposedWidth,proposedHeight)</code>.
     * This happens when the maximum double buffer size has been set for this
     * repaint manager.
     *
     * @param c the component
     * @param proposedWidth the width of the buffer
     * @param proposedHeight the height of the buffer
     *
     * @return the volatile image
     * @see java.awt.image.VolatileImage
     * @since 1.4
     */
    public Image getVolatileOffscreenBuffer(Component c,
                                            int proposedWidth,int proposedHeight) {
        RepaintManager delegate = getDelegate(c);
        if (delegate != null) {
            return delegate.getVolatileOffscreenBuffer(c, proposedWidth,
                                                        proposedHeight);
        }

        // If the window is non-opaque, it's double-buffered at peer's level
        Window w = (c instanceof Window) ? (Window)c : SwingUtilities.getWindowAncestor(c);
        if (!w.isOpaque()) {
            Toolkit tk = Toolkit.getDefaultToolkit();
            if ((tk instanceof SunToolkit) && (((SunToolkit)tk).needUpdateWindow())) {
                return null;
            }
        }

        GraphicsConfiguration config = c.getGraphicsConfiguration();
        if (config == null) {
            config = GraphicsEnvironment.getLocalGraphicsEnvironment().
                            getDefaultScreenDevice().getDefaultConfiguration();
        }
        Dimension maxSize = getDoubleBufferMaximumSize();
        int width = proposedWidth < 1 ? 1 :
            (proposedWidth > maxSize.width? maxSize.width : proposedWidth);
        int height = proposedHeight < 1 ? 1 :
            (proposedHeight > maxSize.height? maxSize.height : proposedHeight);
        VolatileImage image = volatileMap.get(config);
        if (image == null || image.getWidth() < width ||
                             image.getHeight() < height) {
            if (image != null) {
                image.flush();
            }
            image = config.createCompatibleVolatileImage(width, height,
                                                         volatileBufferType);
            volatileMap.put(config, image);
        }
        return image;
    }

    private Image _getOffscreenBuffer(Component c, int proposedWidth, int proposedHeight) {
        Dimension maxSize = getDoubleBufferMaximumSize();
        DoubleBufferInfo doubleBuffer;
        int width, height;

        // If the window is non-opaque, it's double-buffered at peer's level
        Window w = (c instanceof Window) ? (Window)c : SwingUtilities.getWindowAncestor(c);
        if (!w.isOpaque()) {
            Toolkit tk = Toolkit.getDefaultToolkit();
            if ((tk instanceof SunToolkit) && (((SunToolkit)tk).needUpdateWindow())) {
                return null;
            }
        }

        if (standardDoubleBuffer == null) {
            standardDoubleBuffer = new DoubleBufferInfo();
        }
        doubleBuffer = standardDoubleBuffer;

        width = proposedWidth < 1? 1 :
                  (proposedWidth > maxSize.width? maxSize.width : proposedWidth);
        height = proposedHeight < 1? 1 :
                  (proposedHeight > maxSize.height? maxSize.height : proposedHeight);

        if (doubleBuffer.needsReset || (doubleBuffer.image != null &&
                                        (doubleBuffer.size.width < width ||
                                         doubleBuffer.size.height < height))) {
            doubleBuffer.needsReset = false;
            if (doubleBuffer.image != null) {
                doubleBuffer.image.flush();
                doubleBuffer.image = null;
            }
            width = Math.max(doubleBuffer.size.width, width);
            height = Math.max(doubleBuffer.size.height, height);
        }

        Image result = doubleBuffer.image;

        if (doubleBuffer.image == null) {
            result = c.createImage(width , height);
            doubleBuffer.size = new Dimension(width, height);
            if (c instanceof JComponent) {
                ((JComponent)c).setCreatedDoubleBuffer(true);
                doubleBuffer.image = result;
            }
            // JComponent will inform us when it is no longer valid
            // (via removeNotify) we have no such hook to other components,
            // therefore we don't keep a ref to the Component
            // (indirectly through the Image) by stashing the image.
        }
        return result;
    }


    
Set the maximum double buffer size.
Params:
d – the dimension/**
     * Set the maximum double buffer size.
     *
     * @param d the dimension
     */
    public void setDoubleBufferMaximumSize(Dimension d) {
        doubleBufferMaxSize = d;
        if (doubleBufferMaxSize == null) {
            isCustomMaxBufferSizeSet = false;
            clearImages();
        } else {
            isCustomMaxBufferSizeSet = true;
            clearImages(d.width, d.height);
        }
    }

    private void clearImages() {
        clearImages(0, 0);
    }

    private void clearImages(int width, int height) {
        if (standardDoubleBuffer != null && standardDoubleBuffer.image != null) {
            if (standardDoubleBuffer.image.getWidth(null) > width ||
                standardDoubleBuffer.image.getHeight(null) > height) {
                standardDoubleBuffer.image.flush();
                standardDoubleBuffer.image = null;
            }
        }
        // Clear out the VolatileImages
        Iterator<GraphicsConfiguration> gcs = volatileMap.keySet().iterator();
        while (gcs.hasNext()) {
            GraphicsConfiguration gc = gcs.next();
            VolatileImage image = volatileMap.get(gc);
            if (image.getWidth() > width || image.getHeight() > height) {
                image.flush();
                gcs.remove();
            }
        }
    }

    
Returns the maximum double buffer size.
Returns:
a Dimension object representing the maximum size/**
     * Returns the maximum double buffer size.
     *
     * @return a Dimension object representing the maximum size
     */
    public Dimension getDoubleBufferMaximumSize() {
        if (doubleBufferMaxSize == null) {
            try {
                Rectangle virtualBounds = new Rectangle();
                GraphicsEnvironment ge = GraphicsEnvironment.
                                                 getLocalGraphicsEnvironment();
                for (GraphicsDevice gd : ge.getScreenDevices()) {
                    GraphicsConfiguration gc = gd.getDefaultConfiguration();
                    virtualBounds = virtualBounds.union(gc.getBounds());
                }
                doubleBufferMaxSize = new Dimension(virtualBounds.width,
                                                    virtualBounds.height);
            } catch (HeadlessException e) {
                doubleBufferMaxSize = new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
            }
        }
        return doubleBufferMaxSize;
    }

    
Enables or disables double buffering in this RepaintManager.
CAUTION: The default value for this property is set for optimal
paint performance on the given platform and it is not recommended
that programs modify this property directly.
Params:
aFlag –  true to activate double buffering
See Also:
isDoubleBufferingEnabled/**
     * Enables or disables double buffering in this RepaintManager.
     * CAUTION: The default value for this property is set for optimal
     * paint performance on the given platform and it is not recommended
     * that programs modify this property directly.
     *
     * @param aFlag  true to activate double buffering
     * @see #isDoubleBufferingEnabled
     */
    public void setDoubleBufferingEnabled(boolean aFlag) {
        doubleBufferingEnabled = aFlag;
        PaintManager paintManager = getPaintManager();
        if (!aFlag && paintManager.getClass() != PaintManager.class) {
            setPaintManager(new PaintManager());
        }
    }

    
Returns true if this RepaintManager is double buffered.
The default value for this property may vary from platform
to platform.  On platforms where native double buffering
is supported in the AWT, the default value will be false
to avoid unnecessary buffering in Swing.
On platforms where native double buffering is not supported,
the default value will be true.
Returns:
true if this object is double buffered/**
     * Returns true if this RepaintManager is double buffered.
     * The default value for this property may vary from platform
     * to platform.  On platforms where native double buffering
     * is supported in the AWT, the default value will be <code>false</code>
     * to avoid unnecessary buffering in Swing.
     * On platforms where native double buffering is not supported,
     * the default value will be <code>true</code>.
     *
     * @return true if this object is double buffered
     */
    public boolean isDoubleBufferingEnabled() {
        return doubleBufferingEnabled;
    }

    
This resets the double buffer. Actually, it marks the double buffer
as invalid, the double buffer will then be recreated on the next
invocation of getOffscreenBuffer.
/**
     * This resets the double buffer. Actually, it marks the double buffer
     * as invalid, the double buffer will then be recreated on the next
     * invocation of getOffscreenBuffer.
     */
    void resetDoubleBuffer() {
        if (standardDoubleBuffer != null) {
            standardDoubleBuffer.needsReset = true;
        }
    }

    
This resets the volatile double buffer.
/**
     * This resets the volatile double buffer.
     */
    void resetVolatileDoubleBuffer(GraphicsConfiguration gc) {
        Image image = volatileMap.remove(gc);
        if (image != null) {
            image.flush();
        }
    }

    
Returns true if we should use the Image returned
from getVolatileOffscreenBuffer to do double buffering.
/**
     * Returns true if we should use the <code>Image</code> returned
     * from <code>getVolatileOffscreenBuffer</code> to do double buffering.
     */
    boolean useVolatileDoubleBuffer() {
        return volatileImageBufferEnabled;
    }

    
Returns true if the current thread is the thread painting.  This
will return false if no threads are painting.
/**
     * Returns true if the current thread is the thread painting.  This
     * will return false if no threads are painting.
     */
    private synchronized boolean isPaintingThread() {
        return (Thread.currentThread() == paintThread);
    }
    //
    // Paint methods.  You very, VERY rarely need to invoke these.
    // They are invoked directly from JComponent's painting code and
    // when painting happens outside the normal flow: DefaultDesktopManager
    // and JViewport.  If you end up needing these methods in other places be
    // careful that you don't get stuck in a paint loop.
    //

    
Paints a region of a component
Params:
paintingComponent – Component to paint
bufferComponent – Component to obtain buffer for
g – Graphics to paint to
x – X-coordinate
y – Y-coordinate
w – Width
h – Height/**
     * Paints a region of a component
     *
     * @param paintingComponent Component to paint
     * @param bufferComponent Component to obtain buffer for
     * @param g Graphics to paint to
     * @param x X-coordinate
     * @param y Y-coordinate
     * @param w Width
     * @param h Height
     */
    void paint(JComponent paintingComponent,
               JComponent bufferComponent, Graphics g,
               int x, int y, int w, int h) {
        PaintManager paintManager = getPaintManager();
        if (!isPaintingThread()) {
            // We're painting to two threads at once.  PaintManager deals
            // with this a bit better than BufferStrategyPaintManager, use
            // it to avoid possible exceptions/corruption.
            if (paintManager.getClass() != PaintManager.class) {
                paintManager = new PaintManager();
                paintManager.repaintManager = this;
            }
        }
        if (!paintManager.paint(paintingComponent, bufferComponent, g,
                                x, y, w, h)) {
            g.setClip(x, y, w, h);
            paintingComponent.paintToOffscreen(g, x, y, w, h, x + w, y + h);
        }
    }

    
Does a copy area on the specified region.
Params:
clip – Whether or not the copyArea needs to be clipped to the
            Component's bounds./**
     * Does a copy area on the specified region.
     *
     * @param clip Whether or not the copyArea needs to be clipped to the
     *             Component's bounds.
     */
    void copyArea(JComponent c, Graphics g, int x, int y, int w, int h,
                  int deltaX, int deltaY, boolean clip) {
        getPaintManager().copyArea(c, g, x, y, w, h, deltaX, deltaY, clip);
    }

    private java.util.List<RepaintListener> repaintListeners = new ArrayList<>(1);

    private void addRepaintListener(RepaintListener l) {
        repaintListeners.add(l);
    }

    private void removeRepaintListener(RepaintListener l) {
        repaintListeners.remove(l);
    }

    
Notify the attached repaint listeners that an area of the c component has been immediately repainted, that is without scheduling a repaint runnable, due to performing a "blit" (via calling the copyArea method). 
Params:
c – the component
x – the x coordinate of the area
y – the y coordinate of the area
w – the width of the area
h – the height of the area/**
     * Notify the attached repaint listeners that an area of the {@code c} component
     * has been immediately repainted, that is without scheduling a repaint runnable,
     * due to performing a "blit" (via calling the {@code copyArea} method).
     *
     * @param c the component
     * @param x the x coordinate of the area
     * @param y the y coordinate of the area
     * @param w the width of the area
     * @param h the height of the area
     */
    void notifyRepaintPerformed(JComponent c, int x, int y, int w, int h) {
        for (RepaintListener l : repaintListeners) {
            l.repaintPerformed(c, x, y, w, h);
        }
    }

    
Invoked prior to any paint/copyArea method calls.  This will
be followed by an invocation of endPaint.
WARNING: Callers of this method need to wrap the call
in a try/finally, otherwise if an exception is thrown
during the course of painting the RepaintManager may
be left in a state in which the screen is not updated, eg:
repaintManager.beginPaint();
try {
  repaintManager.paint(...);
} finally {
  repaintManager.endPaint();
}

/**
     * Invoked prior to any paint/copyArea method calls.  This will
     * be followed by an invocation of <code>endPaint</code>.
     * <b>WARNING</b>: Callers of this method need to wrap the call
     * in a <code>try/finally</code>, otherwise if an exception is thrown
     * during the course of painting the RepaintManager may
     * be left in a state in which the screen is not updated, eg:
     * <pre>
     * repaintManager.beginPaint();
     * try {
     *   repaintManager.paint(...);
     * } finally {
     *   repaintManager.endPaint();
     * }
     * </pre>
     */
    void beginPaint() {
        boolean multiThreadedPaint = false;
        int paintDepth;
        Thread currentThread = Thread.currentThread();
        synchronized(this) {
            paintDepth = this.paintDepth;
            if (paintThread == null || currentThread == paintThread) {
                paintThread = currentThread;
                this.paintDepth++;
            } else {
                multiThreadedPaint = true;
            }
        }
        if (!multiThreadedPaint && paintDepth == 0) {
            getPaintManager().beginPaint();
        }
    }

    
Invoked after beginPaint has been invoked.
/**
     * Invoked after <code>beginPaint</code> has been invoked.
     */
    void endPaint() {
        if (isPaintingThread()) {
            PaintManager paintManager = null;
            synchronized(this) {
                if (--paintDepth == 0) {
                    paintManager = getPaintManager();
                }
            }
            if (paintManager != null) {
                paintManager.endPaint();
                synchronized(this) {
                    paintThread = null;
                }
            }
        }
    }

    
If possible this will show a previously rendered portion of
a Component.  If successful, this will return true, otherwise false.

WARNING: This method is invoked from the native toolkit thread, be
very careful as to what methods this invokes!
/**
     * If possible this will show a previously rendered portion of
     * a Component.  If successful, this will return true, otherwise false.
     * <p>
     * WARNING: This method is invoked from the native toolkit thread, be
     * very careful as to what methods this invokes!
     */
    boolean show(Container c, int x, int y, int w, int h) {
        return getPaintManager().show(c, x, y, w, h);
    }

    
Invoked when the doubleBuffered or useTrueDoubleBuffering
properties of a JRootPane change.  This may come in on any thread.
/**
     * Invoked when the doubleBuffered or useTrueDoubleBuffering
     * properties of a JRootPane change.  This may come in on any thread.
     */
    void doubleBufferingChanged(JRootPane rootPane) {
        getPaintManager().doubleBufferingChanged(rootPane);
    }

    
Sets the PaintManager that is used to handle all
double buffered painting.
Params:
paintManager – The PaintManager to use.  Passing in null indicates
       the fallback PaintManager should be used./**
     * Sets the <code>PaintManager</code> that is used to handle all
     * double buffered painting.
     *
     * @param paintManager The PaintManager to use.  Passing in null indicates
     *        the fallback PaintManager should be used.
     */
    void setPaintManager(PaintManager paintManager) {
        if (paintManager == null) {
            paintManager = new PaintManager();
        }
        PaintManager oldPaintManager;
        synchronized(this) {
            oldPaintManager = this.paintManager;
            this.paintManager = paintManager;
            paintManager.repaintManager = this;
        }
        if (oldPaintManager != null) {
            oldPaintManager.dispose();
        }
    }

    private synchronized PaintManager getPaintManager() {
        if (paintManager == null) {
            PaintManager paintManager = null;
            if (doubleBufferingEnabled && !nativeDoubleBuffering) {
                switch (bufferStrategyType) {
                case BUFFER_STRATEGY_NOT_SPECIFIED:
                    Toolkit tk = Toolkit.getDefaultToolkit();
                    if (tk instanceof SunToolkit) {
                        SunToolkit stk = (SunToolkit) tk;
                        if (stk.useBufferPerWindow()) {
                            paintManager = new BufferStrategyPaintManager();
                        }
                    }
                    break;
                case BUFFER_STRATEGY_SPECIFIED_ON:
                    paintManager = new BufferStrategyPaintManager();
                    break;
                default:
                    break;
                }
            }
            // null case handled in setPaintManager
            setPaintManager(paintManager);
        }
        return paintManager;
    }

    private void scheduleProcessingRunnable(AppContext context) {
        if (processingRunnable.markPending()) {
            Toolkit tk = Toolkit.getDefaultToolkit();
            if (tk instanceof SunToolkit) {
                SunToolkit.getSystemEventQueueImplPP(context).
                  postEvent(new InvocationEvent(Toolkit.getDefaultToolkit(),
                                                processingRunnable));
            } else {
                Toolkit.getDefaultToolkit().getSystemEventQueue().
                      postEvent(new InvocationEvent(Toolkit.getDefaultToolkit(),
                                                    processingRunnable));
            }
        }
    }


    
PaintManager is used to handle all double buffered painting for
Swing.  Subclasses should call back into the JComponent method
paintToOffscreen to handle the actual painting.
/**
     * PaintManager is used to handle all double buffered painting for
     * Swing.  Subclasses should call back into the JComponent method
     * <code>paintToOffscreen</code> to handle the actual painting.
     */
    static class PaintManager {
        
RepaintManager the PaintManager has been installed on.
/**
         * RepaintManager the PaintManager has been installed on.
         */
        protected RepaintManager repaintManager;
        boolean isRepaintingRoot;

        
Paints a region of a component
Params:
paintingComponent – Component to paint
bufferComponent – Component to obtain buffer for
g – Graphics to paint to
x – X-coordinate
y – Y-coordinate
w – Width
h – Height
Returns:
true if painting was successful./**
         * Paints a region of a component
         *
         * @param paintingComponent Component to paint
         * @param bufferComponent Component to obtain buffer for
         * @param g Graphics to paint to
         * @param x X-coordinate
         * @param y Y-coordinate
         * @param w Width
         * @param h Height
         * @return true if painting was successful.
         */
        public boolean paint(JComponent paintingComponent,
                             JComponent bufferComponent, Graphics g,
                             int x, int y, int w, int h) {
            // First attempt to use VolatileImage buffer for performance.
            // If this fails (which should rarely occur), fallback to a
            // standard Image buffer.
            boolean paintCompleted = false;
            Image offscreen;
            int sw = w + 1;
            int sh = h + 1;

            if (repaintManager.useVolatileDoubleBuffer() &&
                (offscreen = getValidImage(repaintManager.
                getVolatileOffscreenBuffer(bufferComponent, sw, sh))) != null) {
                VolatileImage vImage = (java.awt.image.VolatileImage)offscreen;
                GraphicsConfiguration gc = bufferComponent.
                                            getGraphicsConfiguration();
                for (int i = 0; !paintCompleted &&
                         i < RepaintManager.VOLATILE_LOOP_MAX; i++) {
                    if (vImage.validate(gc) ==
                                   VolatileImage.IMAGE_INCOMPATIBLE) {
                        repaintManager.resetVolatileDoubleBuffer(gc);
                        offscreen = repaintManager.getVolatileOffscreenBuffer(
                            bufferComponent, sw, sh);
                        vImage = (java.awt.image.VolatileImage)offscreen;
                    }
                    paintDoubleBuffered(paintingComponent, vImage, g, x, y,
                                        w, h);
                    paintCompleted = !vImage.contentsLost();
                }
            }
            // VolatileImage painting loop failed, fallback to regular
            // offscreen buffer
            if (!paintCompleted && (offscreen = getValidImage(
                      repaintManager.getOffscreenBuffer(
                      bufferComponent, w, h))) != null) {
                paintDoubleBuffered(paintingComponent, offscreen, g, x, y, w,
                                    h);
                paintCompleted = true;
            }
            return paintCompleted;
        }

        
Does a copy area on the specified region.
/**
         * Does a copy area on the specified region.
         */
        public void copyArea(JComponent c, Graphics g, int x, int y, int w,
                             int h, int deltaX, int deltaY, boolean clip) {
            g.copyArea(x, y, w, h, deltaX, deltaY);
        }

        
Invoked prior to any calls to paint or copyArea.
/**
         * Invoked prior to any calls to paint or copyArea.
         */
        public void beginPaint() {
        }

        
Invoked to indicate painting has been completed.
/**
         * Invoked to indicate painting has been completed.
         */
        public void endPaint() {
        }

        
Shows a region of a previously rendered component.  This
will return true if successful, false otherwise.  The default
implementation returns false.
/**
         * Shows a region of a previously rendered component.  This
         * will return true if successful, false otherwise.  The default
         * implementation returns false.
         */
        public boolean show(Container c, int x, int y, int w, int h) {
            return false;
        }

        
Invoked when the doubleBuffered or useTrueDoubleBuffering
properties of a JRootPane change.  This may come in on any thread.
/**
         * Invoked when the doubleBuffered or useTrueDoubleBuffering
         * properties of a JRootPane change.  This may come in on any thread.
         */
        public void doubleBufferingChanged(JRootPane rootPane) {
        }

        
Paints a portion of a component to an offscreen buffer.
/**
         * Paints a portion of a component to an offscreen buffer.
         */
        protected void paintDoubleBuffered(JComponent c, Image image,
                Graphics g, int clipX, int clipY,
                int clipW, int clipH) {
            if (image instanceof VolatileImage && isPixelsCopying(c, g)) {
                paintDoubleBufferedFPScales(c, image, g, clipX, clipY, clipW, clipH);
            } else {
                paintDoubleBufferedImpl(c, image, g, clipX, clipY, clipW, clipH);
            }
        }

        private void paintDoubleBufferedImpl(JComponent c, Image image,
                                             Graphics g, int clipX, int clipY,
                                             int clipW, int clipH) {
            Graphics osg = image.getGraphics();
            int bw = Math.min(clipW, image.getWidth(null));
            int bh = Math.min(clipH, image.getHeight(null));
            int x,y,maxx,maxy;

            try {
                for(x = clipX, maxx = clipX+clipW; x < maxx ;  x += bw ) {
                    for(y=clipY, maxy = clipY + clipH; y < maxy ; y += bh) {
                        osg.translate(-x, -y);
                        osg.setClip(x,y,bw,bh);
                        if (volatileBufferType != Transparency.OPAQUE
                                && osg instanceof Graphics2D) {
                            final Graphics2D g2d = (Graphics2D) osg;
                            final Color oldBg = g2d.getBackground();
                            g2d.setBackground(c.getBackground());
                            g2d.clearRect(x, y, bw, bh);
                            g2d.setBackground(oldBg);
                        }
                        c.paintToOffscreen(osg, x, y, bw, bh, maxx, maxy);
                        g.setClip(x, y, bw, bh);
                        if (volatileBufferType != Transparency.OPAQUE
                                && g instanceof Graphics2D) {
                            final Graphics2D g2d = (Graphics2D) g;
                            final Composite oldComposite = g2d.getComposite();
                            g2d.setComposite(AlphaComposite.Src);
                            g2d.drawImage(image, x, y, c);
                            g2d.setComposite(oldComposite);
                        } else {
                            g.drawImage(image, x, y, c);
                        }
                        osg.translate(x, y);
                    }
                }
            } finally {
                osg.dispose();
            }
        }

        private void paintDoubleBufferedFPScales(JComponent c, Image image,
                                                 Graphics g, int clipX, int clipY,
                                                 int clipW, int clipH) {
            Graphics osg = image.getGraphics();
            Graphics2D g2d = (Graphics2D) g;
            Graphics2D osg2d = (Graphics2D) osg;

            AffineTransform identity = new AffineTransform();
            int bw = Math.min(clipW, image.getWidth(null));
            int bh = Math.min(clipH, image.getHeight(null));
            int x, y, maxx, maxy;

            AffineTransform tx = g2d.getTransform();
            double scaleX = tx.getScaleX();
            double scaleY = tx.getScaleY();
            double trX = tx.getTranslateX();
            double trY = tx.getTranslateY();

            boolean translucent = volatileBufferType != Transparency.OPAQUE;
            Composite oldComposite = g2d.getComposite();

            try {
                for (x = clipX, maxx = clipX + clipW; x < maxx; x += bw) {
                    for (y = clipY, maxy = clipY + clipH; y < maxy; y += bh) {

                        // draw x, y, bw, bh
                        int pixelx1 = Region.clipRound(x * scaleX + trX);
                        int pixely1 = Region.clipRound(y * scaleY + trY);
                        int pixelx2 = Region.clipRound((x + bw) * scaleX + trX);
                        int pixely2 = Region.clipRound((y + bh) * scaleY + trY);
                        int pixelw = pixelx2 - pixelx1;
                        int pixelh = pixely2 - pixely1;

                        osg2d.setTransform(identity);
                        if (translucent) {
                            final Color oldBg = g2d.getBackground();
                            g2d.setBackground(c.getBackground());
                            g2d.clearRect(pixelx1, pixely1, pixelw, pixelh);
                            g2d.setBackground(oldBg);
                        }

                        osg2d.setClip(0, 0, pixelw, pixelh);
                        osg2d.translate(trX - pixelx1, trY - pixely1);
                        osg2d.scale(scaleX, scaleY);
                        c.paintToOffscreen(osg, x, y, bw, bh, maxx, maxy);

                        g2d.setTransform(identity);
                        g2d.setClip(pixelx1, pixely1, pixelw, pixelh);
                        AffineTransform stx = new AffineTransform();
                        stx.translate(pixelx1, pixely1);
                        stx.scale(scaleX, scaleY);
                        g2d.setTransform(stx);

                        if (translucent) {
                            g2d.setComposite(AlphaComposite.Src);
                        }

                        g2d.drawImage(image, 0, 0, c);

                        if (translucent) {
                            g2d.setComposite(oldComposite);
                        }
                        g2d.setTransform(tx);
                    }
                }
            } finally {
                osg.dispose();
            }
        }

        
If image is non-null with a positive size it
is returned, otherwise null is returned.
/**
         * If <code>image</code> is non-null with a positive size it
         * is returned, otherwise null is returned.
         */
        private Image getValidImage(Image image) {
            if (image != null && image.getWidth(null) > 0 &&
                                 image.getHeight(null) > 0) {
                return image;
            }
            return null;
        }

        
Schedules a repaint for the specified component.  This differs
from root.repaint in that if the RepaintManager is
currently processing paint requests it'll process this request
with the current set of requests.
/**
         * Schedules a repaint for the specified component.  This differs
         * from <code>root.repaint</code> in that if the RepaintManager is
         * currently processing paint requests it'll process this request
         * with the current set of requests.
         */
        protected void repaintRoot(JComponent root) {
            assert (repaintManager.repaintRoot == null);
            if (repaintManager.painting) {
                repaintManager.repaintRoot = root;
            }
            else {
                root.repaint();
            }
        }

        
Returns true if the component being painted is the root component
that was previously passed to repaintRoot.
/**
         * Returns true if the component being painted is the root component
         * that was previously passed to <code>repaintRoot</code>.
         */
        protected boolean isRepaintingRoot() {
            return isRepaintingRoot;
        }

        
Cleans up any state.  After invoked the PaintManager will no
longer be used anymore.
/**
         * Cleans up any state.  After invoked the PaintManager will no
         * longer be used anymore.
         */
        protected void dispose() {
        }

        private boolean isPixelsCopying(JComponent c, Graphics g) {

            AffineTransform tx = getTransform(g);
            GraphicsConfiguration gc = c.getGraphicsConfiguration();

            if (tx == null || gc == null
                    || !SwingUtilities2.isFloatingPointScale(tx)) {
                return false;
            }

            AffineTransform gcTx = gc.getDefaultTransform();

            return gcTx.getScaleX() == tx.getScaleX()
                    && gcTx.getScaleY() == tx.getScaleY();
        }

        private static AffineTransform getTransform(Graphics g) {
            if (g instanceof SunGraphics2D) {
                return ((SunGraphics2D) g).transform;
            } else if (g instanceof Graphics2D) {
                return ((Graphics2D) g).getTransform();
            }
            return null;
        }
    }

    private class DoubleBufferInfo {
        public Image image;
        public Dimension size;
        public boolean needsReset = false;
    }


    
Listener installed to detect display changes. When display changes,
schedules a callback to notify all RepaintManagers of the display
changes. Only one DisplayChangedHandler is ever installed. The
singleton instance will schedule notification for all AppContexts.
/**
     * Listener installed to detect display changes. When display changes,
     * schedules a callback to notify all RepaintManagers of the display
     * changes. Only one DisplayChangedHandler is ever installed. The
     * singleton instance will schedule notification for all AppContexts.
     */
    private static final class DisplayChangedHandler implements
                                             DisplayChangedListener {
        // Empty non private constructor was added because access to this
        // class shouldn't be generated by the compiler using synthetic
        // accessor method
        DisplayChangedHandler() {
        }

        public void displayChanged() {
            scheduleDisplayChanges();
        }

        public void paletteChanged() {
        }

        private static void scheduleDisplayChanges() {
            // To avoid threading problems, we notify each RepaintManager
            // on the thread it was created on.
            for (AppContext context : AppContext.getAppContexts()) {
                synchronized(context) {
                    if (!context.isDisposed()) {
                        EventQueue eventQueue = (EventQueue)context.get(
                            AppContext.EVENT_QUEUE_KEY);
                        if (eventQueue != null) {
                            eventQueue.postEvent(new InvocationEvent(
                                Toolkit.getDefaultToolkit(),
                                new DisplayChangedRunnable()));
                        }
                    }
                }
            }
        }
    }


    private static final class DisplayChangedRunnable implements Runnable {
        public void run() {
            RepaintManager.currentManager((JComponent)null).displayChanged();
        }
    }


    
Runnable used to process all repaint/revalidate requests.
/**
     * Runnable used to process all repaint/revalidate requests.
     */
    private final class ProcessingRunnable implements Runnable {
        // If true, we're wainting on the EventQueue.
        private boolean pending;

        
Marks this processing runnable as pending. If this was not
already marked as pending, true is returned.
/**
         * Marks this processing runnable as pending. If this was not
         * already marked as pending, true is returned.
         */
        public synchronized boolean markPending() {
            if (!pending) {
                pending = true;
                return true;
            }
            return false;
        }

        public void run() {
            synchronized (this) {
                pending = false;
            }
            // First pass, flush any heavy paint events into real paint
            // events.  If there are pending heavy weight requests this will
            // result in q'ing this request up one more time.  As
            // long as no other requests come in between now and the time
            // the second one is processed nothing will happen.  This is not
            // ideal, but the logic needed to suppress the second request is
            // more headache than it's worth.
            scheduleHeavyWeightPaints();
            // Do the actual validation and painting.
            validateInvalidComponents();
            prePaintDirtyRegions();
        }
    }
    private RepaintManager getDelegate(Component c) {
        RepaintManager delegate = SwingUtilities3.getDelegateRepaintManager(c);
        if (this == delegate) {
            delegate = null;
        }
        return delegate;
    }
}