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	/*
	* Copyright (c) 1999, 2007, 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 sun.awt;

	import java.awt.Component;
	import java.awt.Graphics;
	import java.awt.Rectangle;
	import java.awt.event.PaintEvent;

	/**
	* The <code>RepaintArea</code> is a geometric construct created for the
	* purpose of holding the geometry of several coalesced paint events.
	* This geometry is accessed synchronously, although it is written such
	* that painting may still be executed asynchronously.
	*
	* @author Eric Hawkes
	* @since 1.3
	*/
	public class RepaintArea {

	/**
	* Maximum ratio of bounding rectangle to benefit for which
	* both the vertical and horizontal unions are repainted.
	* For smaller ratios the whole bounding rectangle is repainted.
	* @see #paint
	*/
	private static final int MAX_BENEFIT_RATIO = 4;

	private static final int HORIZONTAL = 0;
	private static final int VERTICAL = 1;
	private static final int UPDATE = 2;

	private static final int RECT_COUNT = UPDATE + 1;

	private Rectangle paintRects[] = new Rectangle[RECT_COUNT];


	/**
	* Constructs a new <code>RepaintArea</code>
	* @since 1.3
	*/
	public RepaintArea() {
	}

	/**
	* Constructs a new <code>RepaintArea</code> initialized to match
	* the values of the specified RepaintArea.
	*
	* @param ra the <code>RepaintArea</code> from which to copy initial
	* values to a newly constructed RepaintArea
	* @since 1.3
	*/
	private RepaintArea(RepaintArea ra) {
	// This constructor is private because it should only be called
	// from the cloneAndReset method
	for (int i = 0; i < RECT_COUNT; i++) {
	paintRects[i] = ra.paintRects[i];
	}
	}

	/**
	* Adds a <code>Rectangle</code> to this <code>RepaintArea</code>.
	* PAINT Rectangles are divided into mostly vertical and mostly horizontal.
	* Each group is unioned together.
	* UPDATE Rectangles are unioned.
	*
	* @param r the specified <code>Rectangle</code>
	* @param id possible values PaintEvent.UPDATE or PaintEvent.PAINT
	* @since 1.3
	*/
	public synchronized void add(Rectangle r, int id) {
	// Make sure this new rectangle has positive dimensions
	if (r.isEmpty()) {
	return;
	}
	int addTo = UPDATE;
	if (id == PaintEvent.PAINT) {
	addTo = (r.width > r.height) ? HORIZONTAL : VERTICAL;
	}
	if (paintRects[addTo] != null) {
	paintRects[addTo].add(r);
	} else {
	paintRects[addTo] = new Rectangle(r);
	}
	}


	/**
	* Creates a new <code>RepaintArea</code> with the same geometry as this
	* RepaintArea, then removes all of the geometry from this
	* RepaintArea and restores it to an empty RepaintArea.
	*
	* @return ra a new <code>RepaintArea</code> having the same geometry as
	* this RepaintArea.
	* @since 1.3
	*/
	private synchronized RepaintArea cloneAndReset() {
	RepaintArea ra = new RepaintArea(this);
	for (int i = 0; i < RECT_COUNT; i++) {
	paintRects[i] = null;
	}
	return ra;
	}

	public boolean isEmpty() {
	for (int i = 0; i < RECT_COUNT; i++) {
	if (paintRects[i] != null) {
	return false;
	}
	}
	return true;
	}

	/**
	* Constrains the size of the repaint area to the passed in bounds.
	*/
	public synchronized void constrain(int x, int y, int w, int h) {
	for (int i = 0; i < RECT_COUNT; i++) {
	Rectangle rect = paintRects[i];
	if (rect != null) {
	if (rect.x < x) {
	rect.width -= (x - rect.x);
	rect.x = x;
	}
	if (rect.y < y) {
	rect.height -= (y - rect.y);
	rect.y = y;
	}
	int xDelta = rect.x + rect.width - x - w;
	if (xDelta > 0) {
	rect.width -= xDelta;
	}
	int yDelta = rect.y + rect.height - y - h;
	if (yDelta > 0) {
	rect.height -= yDelta;
	}
	if (rect.width <= 0 \|\| rect.height <= 0) {
	paintRects[i] = null;
	}
	}
	}
	}

	/**
	* Marks the passed in region as not needing to be painted. It's possible
	* this will do nothing.
	*/
	public synchronized void subtract(int x, int y, int w, int h) {
	Rectangle subtract = new Rectangle(x, y, w, h);
	for (int i = 0; i < RECT_COUNT; i++) {
	if (subtract(paintRects[i], subtract)) {
	if (paintRects[i] != null && paintRects[i].isEmpty()) {
	paintRects[i] = null;
	}
	}
	}
	}

	/**
	* Invokes paint and update on target Component with optimal
	* rectangular clip region.
	* If PAINT bounding rectangle is less than
	* MAX_BENEFIT_RATIO times the benefit, then the vertical and horizontal unions are
	* painted separately. Otherwise the entire bounding rectangle is painted.
	*
	* @param target Component to <code>paint</code> or <code>update</code>
	* @since 1.4
	*/
	public void paint(Object target, boolean shouldClearRectBeforePaint) {
	Component comp = (Component)target;

	if (isEmpty()) {
	return;
	}

	if (!comp.isVisible()) {
	return;
	}

	RepaintArea ra = this.cloneAndReset();

	if (!subtract(ra.paintRects[VERTICAL], ra.paintRects[HORIZONTAL])) {
	subtract(ra.paintRects[HORIZONTAL], ra.paintRects[VERTICAL]);
	}

	if (ra.paintRects[HORIZONTAL] != null && ra.paintRects[VERTICAL] != null) {
	Rectangle paintRect = ra.paintRects[HORIZONTAL].union(ra.paintRects[VERTICAL]);
	int square = paintRect.width * paintRect.height;
	int benefit = square - ra.paintRects[HORIZONTAL].width
	* ra.paintRects[HORIZONTAL].height - ra.paintRects[VERTICAL].width
	* ra.paintRects[VERTICAL].height;
	// if benefit is comparable with bounding box
	if (MAX_BENEFIT_RATIO * benefit < square) {
	ra.paintRects[HORIZONTAL] = paintRect;
	ra.paintRects[VERTICAL] = null;
	}
	}
	for (int i = 0; i < paintRects.length; i++) {
	if (ra.paintRects[i] != null
	&& !ra.paintRects[i].isEmpty())
	{
	// Should use separate Graphics for each paint() call,
	// since paint() can change Graphics state for next call.
	Graphics g = comp.getGraphics();
	if (g != null) {
	try {
	g.setClip(ra.paintRects[i]);
	if (i == UPDATE) {
	updateComponent(comp, g);
	} else {
	if (shouldClearRectBeforePaint) {
	g.clearRect( ra.paintRects[i].x,
	ra.paintRects[i].y,
	ra.paintRects[i].width,
	ra.paintRects[i].height);
	}
	paintComponent(comp, g);
	}
	} finally {
	g.dispose();
	}
	}
	}
	}
	}

	/**
	* Calls <code>Component.update(Graphics)</code> with given Graphics.
	*/
	protected void updateComponent(Component comp, Graphics g) {
	if (comp != null) {
	comp.update(g);
	}
	}

	/**
	* Calls <code>Component.paint(Graphics)</code> with given Graphics.
	*/
	protected void paintComponent(Component comp, Graphics g) {
	if (comp != null) {
	comp.paint(g);
	}
	}

	/**
	* Subtracts subtr from rect. If the result is rectangle
	* changes rect and returns true. Otherwise false.
	*/
	static boolean subtract(Rectangle rect, Rectangle subtr) {
	if (rect == null \|\| subtr == null) {
	return true;
	}
	Rectangle common = rect.intersection(subtr);
	if (common.isEmpty()) {
	return true;
	}
	if (rect.x == common.x && rect.y == common.y) {
	if (rect.width == common.width) {
	rect.y += common.height;
	rect.height -= common.height;
	return true;
	} else
	if (rect.height == common.height) {
	rect.x += common.width;
	rect.width -= common.width;
	return true;
	}
	} else
	if (rect.x + rect.width == common.x + common.width
	&& rect.y + rect.height == common.y + common.height)
	{
	if (rect.width == common.width) {
	rect.height -= common.height;
	return true;
	} else
	if (rect.height == common.height) {
	rect.width -= common.width;
	return true;
	}
	}
	return false;
	}

	public String toString() {
	return super.toString() + "[ horizontal=" + paintRects[0] +
	" vertical=" + paintRects[1] +
	" update=" + paintRects[2] + "]";
	}
	}

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