qt-everywhere-src-5.14.1/qt3d/src/extras/text/areaallocator.cpp - orbit - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the QtQuick module of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:LGPL$
 ** Commercial License Usage
 ** Licensees holding valid commercial Qt licenses may use this file in
 ** accordance with the commercial license agreement provided with the
 ** Software or, alternatively, in accordance with the terms contained in
 ** a written agreement between you and The Qt Company. For licensing terms
 ** and conditions see https://www.qt.io/terms-conditions. For further
 ** information use the contact form at https://www.qt.io/contact-us.
 **
 ** GNU Lesser General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU Lesser
 ** General Public License version 3 as published by the Free Software
 ** Foundation and appearing in the file LICENSE.LGPL3 included in the
 ** packaging of this file. Please review the following information to
 ** ensure the GNU Lesser General Public License version 3 requirements
 ** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
 **
 ** GNU General Public License Usage
 ** Alternatively, this file may be used under the terms of the GNU
 ** General Public License version 2.0 or (at your option) the GNU General
 ** Public license version 3 or any later version approved by the KDE Free
 ** Qt Foundation. The licenses are as published by the Free Software
 ** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
 ** included in the packaging of this file. Please review the following
 ** information to ensure the GNU General Public License requirements will
 ** be met: https://www.gnu.org/licenses/gpl-2.0.html and
 ** https://www.gnu.org/licenses/gpl-3.0.html.
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "areaallocator_p.h"

 #include <QtCore/qglobal.h>
 #include <QtCore/qrect.h>
 #include <QtCore/qpoint.h>

 //
 // This file is copied from qtdeclarative/src/quick/scenegraph/util/qsgareaallocator.cpp
 //

 QT_BEGIN_NAMESPACE

 namespace Qt3DExtras {

 namespace
 {
     enum SplitType
     {
         VerticalSplit,
         HorizontalSplit
     };

     static const int maxMargin = 2;
 }

 struct AreaAllocatorNode
 {
     AreaAllocatorNode(AreaAllocatorNode *parent);
     ~AreaAllocatorNode();
     inline bool isLeaf();

     AreaAllocatorNode *parent;
     AreaAllocatorNode *left;
     AreaAllocatorNode *right;
     int split; // only valid for inner nodes.
     SplitType splitType;
     bool isOccupied; // only valid for leaf nodes.
 };

 AreaAllocatorNode::AreaAllocatorNode(AreaAllocatorNode *parent)
     : parent(parent)
     , left(0)
     , right(0)
     , isOccupied(false)
 {
 }

 AreaAllocatorNode::~AreaAllocatorNode()
 {
     delete left;
     delete right;
 }

 bool AreaAllocatorNode::isLeaf()
 {
     Q_ASSERT((left != 0) == (right != 0));
     return !left;
 }


 AreaAllocator::AreaAllocator(const QSize &size) : m_size(size)
 {
     m_root = new AreaAllocatorNode(0);
 }

 AreaAllocator::~AreaAllocator()
 {
     delete m_root;
 }

 QRect AreaAllocator::allocate(const QSize &size)
 {
     QPoint point;
     bool result = allocateInNode(size, point, QRect(QPoint(0, 0), m_size), m_root);
     return result ? QRect(point, size) : QRect();
 }

 bool AreaAllocator::deallocate(const QRect &rect)
 {
     return deallocateInNode(rect.topLeft(), m_root);
 }

 bool AreaAllocator::allocateInNode(const QSize &size, QPoint &result, const QRect &currentRect, AreaAllocatorNode *node)
 {
     if (size.width() > currentRect.width() || size.height() > currentRect.height())
         return false;

     if (node->isLeaf()) {
         if (node->isOccupied)
             return false;
         if (size.width() + maxMargin >= currentRect.width() && size.height() + maxMargin >= currentRect.height()) {
             //Snug fit, occupy entire rectangle.
             node->isOccupied = true;
             result = currentRect.topLeft();
             return true;
         }
         // TODO: Reuse nodes.
         // Split node.
         node->left = new AreaAllocatorNode(node);
         node->right = new AreaAllocatorNode(node);
         QRect splitRect = currentRect;
         if ((currentRect.width() - size.width()) * currentRect.height() < (currentRect.height() - size.height()) * currentRect.width()) {
             node->splitType = HorizontalSplit;
             node->split = currentRect.top() + size.height();
             splitRect.setHeight(size.height());
         } else {
             node->splitType = VerticalSplit;
             node->split = currentRect.left() + size.width();
             splitRect.setWidth(size.width());
         }
         return allocateInNode(size, result, splitRect, node->left);
     } else {
         // TODO: avoid unnecessary recursion.
         //  has been split.
         QRect leftRect = currentRect;
         QRect rightRect = currentRect;
         if (node->splitType == HorizontalSplit) {
             leftRect.setHeight(node->split - leftRect.top());
             rightRect.setTop(node->split);
         } else {
             leftRect.setWidth(node->split - leftRect.left());
             rightRect.setLeft(node->split);
         }
         if (allocateInNode(size, result, leftRect, node->left))
             return true;
         if (allocateInNode(size, result, rightRect, node->right))
             return true;
         return false;
     }
 }

 bool AreaAllocator::deallocateInNode(const QPoint &pos, AreaAllocatorNode *node)
 {
     while (!node->isLeaf()) {
         //  has been split.
         int cmp = node->splitType == HorizontalSplit ? pos.y() : pos.x();
         node = cmp < node->split ? node->left : node->right;
     }
     if (!node->isOccupied)
         return false;
     node->isOccupied = false;
     mergeNodeWithNeighbors(node);
     return true;
 }

 void AreaAllocator::mergeNodeWithNeighbors(AreaAllocatorNode *node)
 {
     bool done = false;
     AreaAllocatorNode *parent = 0;
     AreaAllocatorNode *current = 0;
     AreaAllocatorNode *sibling;
     while (!done) {
         Q_ASSERT(node->isLeaf());
         Q_ASSERT(!node->isOccupied);
         if (node->parent == 0)
             return; // No neighbors.

         SplitType splitType = SplitType(node->parent->splitType);
         done = true;

         /* Special case. Might be faster than going through the general code path.
         // Merge with sibling.
         parent = node->parent;
         sibling = (node == parent->left ? parent->right : parent->left);
         if (sibling->isLeaf() && !sibling->isOccupied) {
             Q_ASSERT(!sibling->right);
             node = parent;
             parent->isOccupied = false;
             delete parent->left;
             delete parent->right;
             parent->left = parent->right = 0;
             done = false;
             continue;
         }
         */

         // Merge with left neighbor.
         current = node;
         parent = current->parent;
         while (parent && current == parent->left && parent->splitType == splitType) {
             current = parent;
             parent = parent->parent;
         }

         if (parent && parent->splitType == splitType) {
             Q_ASSERT(current == parent->right);
             Q_ASSERT(parent->left);

             AreaAllocatorNode *neighbor = parent->left;
             while (neighbor->right && neighbor->splitType == splitType)
                 neighbor = neighbor->right;

             if (neighbor->isLeaf() && neighbor->parent->splitType == splitType && !neighbor->isOccupied) {
                 // Left neighbor can be merged.
                 parent->split = neighbor->parent->split;

                 parent = neighbor->parent;
                 sibling = neighbor == parent->left ? parent->right : parent->left;
                 AreaAllocatorNode **nodeRef = &m_root;
                 if (parent->parent) {
                     if (parent == parent->parent->left)
                         nodeRef = &parent->parent->left;
                     else
                         nodeRef = &parent->parent->right;
                 }
                 sibling->parent = parent->parent;
                 *nodeRef = sibling;
                 parent->left = parent->right = 0;
                 delete parent;
                 delete neighbor;
                 done = false;
             }
         }

         // Merge with right neighbor.
         current = node;
         parent = current->parent;
         while (parent && current == parent->right && parent->splitType == splitType) {
             current = parent;
             parent = parent->parent;
         }

         if (parent && parent->splitType == splitType) {
             Q_ASSERT(current == parent->left);
             Q_ASSERT(parent->right);

             AreaAllocatorNode *neighbor = parent->right;
             while (neighbor->left && neighbor->splitType == splitType)
                 neighbor = neighbor->left;

             if (neighbor->isLeaf() && neighbor->parent->splitType == splitType && !neighbor->isOccupied) {
                 // Right neighbor can be merged.
                 parent->split = neighbor->parent->split;

                 parent = neighbor->parent;
                 sibling = neighbor == parent->left ? parent->right : parent->left;
                 AreaAllocatorNode **nodeRef = &m_root;
                 if (parent->parent) {
                     if (parent == parent->parent->left)
                         nodeRef = &parent->parent->left;
                     else
                         nodeRef = &parent->parent->right;
                 }
                 sibling->parent = parent->parent;
                 *nodeRef = sibling;
                 parent->left = parent->right = 0;
                 delete parent;
                 delete neighbor;
                 done = false;
             }
         }
     } // end while (!done)
 }

 } // namespace Qt3DExtras

 QT_END_NAMESPACE
	/****************************************************************************
	**
	** Copyright (C) 2016 The Qt Company Ltd.
	** Contact: https://www.qt.io/licensing/
	**
	** This file is part of the QtQuick module of the Qt Toolkit.
	**
	** $QT_BEGIN_LICENSE:LGPL$
	** Commercial License Usage
	** Licensees holding valid commercial Qt licenses may use this file in
	** accordance with the commercial license agreement provided with the
	** Software or, alternatively, in accordance with the terms contained in
	** a written agreement between you and The Qt Company. For licensing terms
	** and conditions see https://www.qt.io/terms-conditions. For further
	** information use the contact form at https://www.qt.io/contact-us.
	**
	** GNU Lesser General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU Lesser
	** General Public License version 3 as published by the Free Software
	** Foundation and appearing in the file LICENSE.LGPL3 included in the
	** packaging of this file. Please review the following information to
	** ensure the GNU Lesser General Public License version 3 requirements
	** will be met: https://www.gnu.org/licenses/lgpl-3.0.html.
	**
	** GNU General Public License Usage
	** Alternatively, this file may be used under the terms of the GNU
	** General Public License version 2.0 or (at your option) the GNU General
	** Public license version 3 or any later version approved by the KDE Free
	** Qt Foundation. The licenses are as published by the Free Software
	** Foundation and appearing in the file LICENSE.GPL2 and LICENSE.GPL3
	** included in the packaging of this file. Please review the following
	** information to ensure the GNU General Public License requirements will
	** be met: https://www.gnu.org/licenses/gpl-2.0.html and
	** https://www.gnu.org/licenses/gpl-3.0.html.
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/

	#include "areaallocator_p.h"

	#include <QtCore/qglobal.h>
	#include <QtCore/qrect.h>
	#include <QtCore/qpoint.h>

	//
	// This file is copied from qtdeclarative/src/quick/scenegraph/util/qsgareaallocator.cpp
	//

	QT_BEGIN_NAMESPACE

	namespace Qt3DExtras {

	namespace
	{
	enum SplitType
	{
	VerticalSplit,
	HorizontalSplit
	};

	static const int maxMargin = 2;
	}

	struct AreaAllocatorNode
	{
	AreaAllocatorNode(AreaAllocatorNode *parent);
	~AreaAllocatorNode();
	inline bool isLeaf();

	AreaAllocatorNode *parent;
	AreaAllocatorNode *left;
	AreaAllocatorNode *right;
	int split; // only valid for inner nodes.
	SplitType splitType;
	bool isOccupied; // only valid for leaf nodes.
	};

	AreaAllocatorNode::AreaAllocatorNode(AreaAllocatorNode *parent)
	: parent(parent)
	, left(0)
	, right(0)
	, isOccupied(false)
	{
	}

	AreaAllocatorNode::~AreaAllocatorNode()
	{
	delete left;
	delete right;
	}

	bool AreaAllocatorNode::isLeaf()
	{
	Q_ASSERT((left != 0) == (right != 0));
	return !left;
	}


	AreaAllocator::AreaAllocator(const QSize &size) : m_size(size)
	{
	m_root = new AreaAllocatorNode(0);
	}

	AreaAllocator::~AreaAllocator()
	{
	delete m_root;
	}

	QRect AreaAllocator::allocate(const QSize &size)
	{
	QPoint point;
	bool result = allocateInNode(size, point, QRect(QPoint(0, 0), m_size), m_root);
	return result ? QRect(point, size) : QRect();
	}

	bool AreaAllocator::deallocate(const QRect &rect)
	{
	return deallocateInNode(rect.topLeft(), m_root);
	}

	bool AreaAllocator::allocateInNode(const QSize &size, QPoint &result, const QRect &currentRect, AreaAllocatorNode *node)
	{
	if (size.width() > currentRect.width() \|\| size.height() > currentRect.height())
	return false;

	if (node->isLeaf()) {
	if (node->isOccupied)
	return false;
	if (size.width() + maxMargin >= currentRect.width() && size.height() + maxMargin >= currentRect.height()) {
	//Snug fit, occupy entire rectangle.
	node->isOccupied = true;
	result = currentRect.topLeft();
	return true;
	}
	// TODO: Reuse nodes.
	// Split node.
	node->left = new AreaAllocatorNode(node);
	node->right = new AreaAllocatorNode(node);
	QRect splitRect = currentRect;
	if ((currentRect.width() - size.width()) * currentRect.height() < (currentRect.height() - size.height()) * currentRect.width()) {
	node->splitType = HorizontalSplit;
	node->split = currentRect.top() + size.height();
	splitRect.setHeight(size.height());
	} else {
	node->splitType = VerticalSplit;
	node->split = currentRect.left() + size.width();
	splitRect.setWidth(size.width());
	}
	return allocateInNode(size, result, splitRect, node->left);
	} else {
	// TODO: avoid unnecessary recursion.
	// has been split.
	QRect leftRect = currentRect;
	QRect rightRect = currentRect;
	if (node->splitType == HorizontalSplit) {
	leftRect.setHeight(node->split - leftRect.top());
	rightRect.setTop(node->split);
	} else {
	leftRect.setWidth(node->split - leftRect.left());
	rightRect.setLeft(node->split);
	}
	if (allocateInNode(size, result, leftRect, node->left))
	return true;
	if (allocateInNode(size, result, rightRect, node->right))
	return true;
	return false;
	}
	}

	bool AreaAllocator::deallocateInNode(const QPoint &pos, AreaAllocatorNode *node)
	{
	while (!node->isLeaf()) {
	// has been split.
	int cmp = node->splitType == HorizontalSplit ? pos.y() : pos.x();
	node = cmp < node->split ? node->left : node->right;
	}
	if (!node->isOccupied)
	return false;
	node->isOccupied = false;
	mergeNodeWithNeighbors(node);
	return true;
	}

	void AreaAllocator::mergeNodeWithNeighbors(AreaAllocatorNode *node)
	{
	bool done = false;
	AreaAllocatorNode *parent = 0;
	AreaAllocatorNode *current = 0;
	AreaAllocatorNode *sibling;
	while (!done) {
	Q_ASSERT(node->isLeaf());
	Q_ASSERT(!node->isOccupied);
	if (node->parent == 0)
	return; // No neighbors.

	SplitType splitType = SplitType(node->parent->splitType);
	done = true;

	/* Special case. Might be faster than going through the general code path.
	// Merge with sibling.
	parent = node->parent;
	sibling = (node == parent->left ? parent->right : parent->left);
	if (sibling->isLeaf() && !sibling->isOccupied) {
	Q_ASSERT(!sibling->right);
	node = parent;
	parent->isOccupied = false;
	delete parent->left;
	delete parent->right;
	parent->left = parent->right = 0;
	done = false;
	continue;
	}
	*/

	// Merge with left neighbor.
	current = node;
	parent = current->parent;
	while (parent && current == parent->left && parent->splitType == splitType) {
	current = parent;
	parent = parent->parent;
	}

	if (parent && parent->splitType == splitType) {
	Q_ASSERT(current == parent->right);
	Q_ASSERT(parent->left);

	AreaAllocatorNode *neighbor = parent->left;
	while (neighbor->right && neighbor->splitType == splitType)
	neighbor = neighbor->right;

	if (neighbor->isLeaf() && neighbor->parent->splitType == splitType && !neighbor->isOccupied) {
	// Left neighbor can be merged.
	parent->split = neighbor->parent->split;

	parent = neighbor->parent;
	sibling = neighbor == parent->left ? parent->right : parent->left;
	AreaAllocatorNode **nodeRef = &m_root;
	if (parent->parent) {
	if (parent == parent->parent->left)
	nodeRef = &parent->parent->left;
	else
	nodeRef = &parent->parent->right;
	}
	sibling->parent = parent->parent;
	*nodeRef = sibling;
	parent->left = parent->right = 0;
	delete parent;
	delete neighbor;
	done = false;
	}
	}

	// Merge with right neighbor.
	current = node;
	parent = current->parent;
	while (parent && current == parent->right && parent->splitType == splitType) {
	current = parent;
	parent = parent->parent;
	}

	if (parent && parent->splitType == splitType) {
	Q_ASSERT(current == parent->left);
	Q_ASSERT(parent->right);

	AreaAllocatorNode *neighbor = parent->right;
	while (neighbor->left && neighbor->splitType == splitType)
	neighbor = neighbor->left;

	if (neighbor->isLeaf() && neighbor->parent->splitType == splitType && !neighbor->isOccupied) {
	// Right neighbor can be merged.
	parent->split = neighbor->parent->split;

	parent = neighbor->parent;
	sibling = neighbor == parent->left ? parent->right : parent->left;
	AreaAllocatorNode **nodeRef = &m_root;
	if (parent->parent) {
	if (parent == parent->parent->left)
	nodeRef = &parent->parent->left;
	else
	nodeRef = &parent->parent->right;
	}
	sibling->parent = parent->parent;
	*nodeRef = sibling;
	parent->left = parent->right = 0;
	delete parent;
	delete neighbor;
	done = false;
	}
	}
	} // end while (!done)
	}

	} // namespace Qt3DExtras

	QT_END_NAMESPACE