qt-everywhere-src-5.14.1/qtbase/examples/widgets/tools/undo/mainwindow.cpp - orbit - Git at Google

 /****************************************************************************
 **
 ** Copyright (C) 2016 The Qt Company Ltd.
 ** Contact: https://www.qt.io/licensing/
 **
 ** This file is part of the demonstration applications of the Qt Toolkit.
 **
 ** $QT_BEGIN_LICENSE:BSD$
 ** 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.
 **
 ** BSD License Usage
 ** Alternatively, you may use this file under the terms of the BSD license
 ** as follows:
 **
 ** "Redistribution and use in source and binary forms, with or without
 ** modification, are permitted provided that the following conditions are
 ** met:
 **   * Redistributions of source code must retain the above copyright
 **     notice, this list of conditions and the following disclaimer.
 **   * Redistributions in binary form must reproduce the above copyright
 **     notice, this list of conditions and the following disclaimer in
 **     the documentation and/or other materials provided with the
 **     distribution.
 **   * Neither the name of The Qt Company Ltd nor the names of its
 **     contributors may be used to endorse or promote products derived
 **     from this software without specific prior written permission.
 **
 **
 ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
 **
 ** $QT_END_LICENSE$
 **
 ****************************************************************************/

 #include "mainwindow.h"
 #include "document.h"
 #include "commands.h"

 #include <QUndoGroup>
 #include <QUndoStack>
 #include <QFileDialog>
 #include <QMessageBox>
 #include <QRandomGenerator>
 #include <QTextStream>
 #include <QToolButton>

 MainWindow::MainWindow(QWidget *parent)
     : QMainWindow(parent)
 {
     setupUi(this);

     QWidget *w = documentTabs->widget(0);
     documentTabs->removeTab(0);
     delete w;

     connect(actionOpen, &QAction::triggered, this, &MainWindow::openDocument);
     connect(actionClose, &QAction::triggered, this, &MainWindow::closeDocument);
     connect(actionNew, &QAction::triggered, this, &MainWindow::newDocument);
     connect(actionSave, &QAction::triggered, this, &MainWindow::saveDocument);
     connect(actionExit, &QAction::triggered, this, &QWidget::close);
     connect(actionRed, &QAction::triggered, this, &MainWindow::setShapeColor);
     connect(actionGreen, &QAction::triggered, this, &MainWindow::setShapeColor);
     connect(actionBlue, &QAction::triggered, this, &MainWindow::setShapeColor);
     connect(actionAddCircle, &QAction::triggered, this, &MainWindow::addShape);
     connect(actionAddRectangle, &QAction::triggered, this, &MainWindow::addShape);
     connect(actionAddTriangle, &QAction::triggered, this, &MainWindow::addShape);
     connect(actionRemoveShape, &QAction::triggered, this, &MainWindow::removeShape);
     connect(actionAddRobot, &QAction::triggered, this, &MainWindow::addRobot);
     connect(actionAddSnowman, &QAction::triggered, this, &MainWindow::addSnowman);
     connect(actionAbout, &QAction::triggered, this, &MainWindow::about);
     connect(actionAboutQt, &QAction::triggered, this, &MainWindow::aboutQt);

     connect(undoLimit, QOverload<int>::of(&QSpinBox::valueChanged), this, &MainWindow::updateActions);
     connect(documentTabs, &QTabWidget::currentChanged, this, &MainWindow::updateActions);

     actionOpen->setShortcut(QString("Ctrl+O"));
     actionClose->setShortcut(QString("Ctrl+W"));
     actionNew->setShortcut(QString("Ctrl+N"));
     actionSave->setShortcut(QString("Ctrl+S"));
     actionExit->setShortcut(QString("Ctrl+Q"));
     actionRemoveShape->setShortcut(QString("Del"));
     actionRed->setShortcut(QString("Alt+R"));
     actionGreen->setShortcut(QString("Alt+G"));
     actionBlue->setShortcut(QString("Alt+B"));
     actionAddCircle->setShortcut(QString("Alt+C"));
     actionAddRectangle->setShortcut(QString("Alt+L"));
     actionAddTriangle->setShortcut(QString("Alt+T"));

     m_undoGroup = new QUndoGroup(this);
     undoView->setGroup(m_undoGroup);
     undoView->setCleanIcon(QIcon(":/icons/ok.png"));

     QAction *undoAction = m_undoGroup->createUndoAction(this);
     QAction *redoAction = m_undoGroup->createRedoAction(this);
     undoAction->setIcon(QIcon(":/icons/undo.png"));
     redoAction->setIcon(QIcon(":/icons/redo.png"));
     menuShape->insertAction(menuShape->actions().at(0), undoAction);
     menuShape->insertAction(undoAction, redoAction);

     toolBar->addAction(undoAction);
     toolBar->addAction(redoAction);

     newDocument();
     updateActions();
 };

 void MainWindow::updateActions()
 {
     Document *doc = currentDocument();
     m_undoGroup->setActiveStack(doc == nullptr ? nullptr : doc->undoStack());
     QString shapeName = doc == nullptr ? QString() : doc->currentShapeName();

     actionAddRobot->setEnabled(doc != nullptr);
     actionAddSnowman->setEnabled(doc != nullptr);
     actionAddCircle->setEnabled(doc != nullptr);
     actionAddRectangle->setEnabled(doc != nullptr);
     actionAddTriangle->setEnabled(doc != nullptr);
     actionClose->setEnabled(doc != nullptr);
     actionSave->setEnabled(doc != nullptr && !doc->undoStack()->isClean());
     undoLimit->setEnabled(doc != nullptr && doc->undoStack()->count() == 0);

     if (shapeName.isEmpty()) {
         actionRed->setEnabled(false);
         actionGreen->setEnabled(false);
         actionBlue->setEnabled(false);
         actionRemoveShape->setEnabled(false);
     } else {
         Shape shape = doc->shape(shapeName);
         actionRed->setEnabled(shape.color() != Qt::red);
         actionGreen->setEnabled(shape.color() != Qt::green);
         actionBlue->setEnabled(shape.color() != Qt::blue);
         actionRemoveShape->setEnabled(true);
     }

     if (doc != nullptr) {
         int index = documentTabs->indexOf(doc);
         Q_ASSERT(index != -1);
         static const QIcon unsavedIcon(":/icons/filesave.png");
         documentTabs->setTabIcon(index, doc->undoStack()->isClean() ? QIcon() : unsavedIcon);

         if (doc->undoStack()->count() == 0)
             doc->undoStack()->setUndoLimit(undoLimit->value());
     }
 }

 void MainWindow::openDocument()
 {
     QString fileName = QFileDialog::getOpenFileName(this);
     if (fileName.isEmpty())
         return;

     QFile file(fileName);
     if (!file.open(QIODevice::ReadOnly)) {
         QMessageBox::warning(this,
                             tr("File error"),
                             tr("Failed to open\n%1").arg(fileName));
         return;
     }
     QTextStream stream(&file);

     Document *doc = new Document();
     if (!doc->load(stream)) {
         QMessageBox::warning(this,
                             tr("Parse error"),
                             tr("Failed to parse\n%1").arg(fileName));
         delete doc;
         return;
     }

     doc->setFileName(fileName);
     addDocument(doc);
 }

 QString MainWindow::fixedWindowTitle(const Document *doc) const
 {
     QString title = doc->fileName();

     if (title.isEmpty())
         title = tr("Unnamed");
     else
         title = QFileInfo(title).fileName();

     QString result;

     for (int i = 0; ; ++i) {
         result = title;
         if (i > 0)
             result += QString::number(i);

         bool unique = true;
         for (int j = 0; j < documentTabs->count(); ++j) {
             const QWidget *widget = documentTabs->widget(j);
             if (widget == doc)
                 continue;
             if (result == documentTabs->tabText(j)) {
                 unique = false;
                 break;
             }
         }

         if (unique)
             break;
     }

     return result;
 }

 void MainWindow::addDocument(Document *doc)
 {
     if (documentTabs->indexOf(doc) != -1)
         return;
     m_undoGroup->addStack(doc->undoStack());
     documentTabs->addTab(doc, fixedWindowTitle(doc));
     connect(doc, &Document::currentShapeChanged, this, &MainWindow::updateActions);
     connect(doc->undoStack(), &QUndoStack::indexChanged, this, &MainWindow::updateActions);
     connect(doc->undoStack(), &QUndoStack::cleanChanged, this, &MainWindow::updateActions);

     setCurrentDocument(doc);
 }

 void MainWindow::setCurrentDocument(Document *doc)
 {
     documentTabs->setCurrentWidget(doc);
 }

 Document *MainWindow::currentDocument() const
 {
     return qobject_cast<Document*>(documentTabs->currentWidget());
 }

 void MainWindow::removeDocument(Document *doc)
 {
     int index = documentTabs->indexOf(doc);
     if (index == -1)
         return;

     documentTabs->removeTab(index);
     m_undoGroup->removeStack(doc->undoStack());
     disconnect(doc, &Document::currentShapeChanged, this, &MainWindow::updateActions);
     disconnect(doc->undoStack(), &QUndoStack::indexChanged, this, &MainWindow::updateActions);
     disconnect(doc->undoStack(), &QUndoStack::cleanChanged, this, &MainWindow::updateActions);

     if (documentTabs->count() == 0) {
         newDocument();
         updateActions();
     }
 }

 void MainWindow::saveDocument()
 {
     Document *doc = currentDocument();
     if (doc == nullptr)
         return;

     for (;;) {
         QString fileName = doc->fileName();

         if (fileName.isEmpty())
             fileName = QFileDialog::getSaveFileName(this);
         if (fileName.isEmpty())
             break;

         QFile file(fileName);
         if (!file.open(QIODevice::WriteOnly)) {
             QMessageBox::warning(this,
                                 tr("File error"),
                                 tr("Failed to open\n%1").arg(fileName));
             doc->setFileName(QString());
         } else {
             QTextStream stream(&file);
             doc->save(stream);
             doc->setFileName(fileName);

             int index = documentTabs->indexOf(doc);
             Q_ASSERT(index != -1);
             documentTabs->setTabText(index, fixedWindowTitle(doc));

             break;
         }
     }
 }

 void MainWindow::closeDocument()
 {
     Document *doc = currentDocument();
     if (doc == nullptr)
         return;

     if (!doc->undoStack()->isClean()) {
         int button
             = QMessageBox::warning(this,
                             tr("Unsaved changes"),
                             tr("Would you like to save this document?"),
                             QMessageBox::Yes, QMessageBox::No);
         if (button == QMessageBox::Yes)
             saveDocument();
     }

     removeDocument(doc);
     delete doc;
 }

 void MainWindow::newDocument()
 {
     addDocument(new Document());
 }

 static QColor randomColor()
 {
     int r = QRandomGenerator::global()->bounded(3);
     switch (r) {
         case 0:
             return Qt::red;
         case 1:
             return Qt::green;
         default:
             break;
     }
     return Qt::blue;
 }

 static QRect randomRect(const QSize &s)
 {
     QSize min = Shape::minSize;

     int left = qRound((s.width() - min.width()) * (QRandomGenerator::global()->bounded(1.0)));
     int top = qRound((s.height() - min.height()) * (QRandomGenerator::global()->bounded(1.0)));
     int width = qRound((s.width() - left - min.width()) * (QRandomGenerator::global()->bounded(1.0))) + min.width();
     int height = qRound((s.height() - top - min.height()) * (QRandomGenerator::global()->bounded(1.0))) + min.height();

     return QRect(left, top, width, height);
 }

 void MainWindow::addShape()
 {
     Document *doc = currentDocument();
     if (doc == nullptr)
         return;

     Shape::Type type;

     if (sender() == actionAddCircle)
         type = Shape::Circle;
     else if (sender() == actionAddRectangle)
         type = Shape::Rectangle;
     else if (sender() == actionAddTriangle)
         type = Shape::Triangle;
     else return;

     Shape newShape(type, randomColor(), randomRect(doc->size()));
     doc->undoStack()->push(new AddShapeCommand(doc, newShape));
 }

 void MainWindow::removeShape()
 {
     Document *doc = currentDocument();
     if (doc == nullptr)
         return;

     QString shapeName = doc->currentShapeName();
     if (shapeName.isEmpty())
         return;

     doc->undoStack()->push(new RemoveShapeCommand(doc, shapeName));
 }

 void MainWindow::setShapeColor()
 {
     Document *doc = currentDocument();
     if (doc == nullptr)
         return;

     QString shapeName = doc->currentShapeName();
     if (shapeName.isEmpty())
         return;

     QColor color;

     if (sender() == actionRed)
         color = Qt::red;
     else if (sender() == actionGreen)
         color = Qt::green;
     else if (sender() == actionBlue)
         color = Qt::blue;
     else
         return;

     if (color == doc->shape(shapeName).color())
         return;

     doc->undoStack()->push(new SetShapeColorCommand(doc, shapeName, color));
 }

 void MainWindow::addSnowman()
 {
     Document *doc = currentDocument();
     if (doc == nullptr)
         return;

     // Create a macro command using beginMacro() and endMacro()

     doc->undoStack()->beginMacro(tr("Add snowman"));
     doc->undoStack()->push(new AddShapeCommand(doc,
                             Shape(Shape::Circle, Qt::blue, QRect(51, 30, 97, 95))));
     doc->undoStack()->push(new AddShapeCommand(doc,
                             Shape(Shape::Circle, Qt::blue, QRect(27, 123, 150, 133))));
     doc->undoStack()->push(new AddShapeCommand(doc,
                             Shape(Shape::Circle, Qt::blue, QRect(11, 253, 188, 146))));
     doc->undoStack()->endMacro();
 }

 void MainWindow::addRobot()
 {
     Document *doc = currentDocument();
     if (doc == nullptr)
         return;

     // Compose a macro command by explicitly adding children to a parent command

     QUndoCommand *parent = new QUndoCommand(tr("Add robot"));

     new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(115, 15, 81, 70)), parent);
     new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(82, 89, 148, 188)), parent);
     new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(76, 280, 80, 165)), parent);
     new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(163, 280, 80, 164)), parent);
     new AddShapeCommand(doc, Shape(Shape::Circle, Qt::blue, QRect(116, 25, 80, 50)), parent);
     new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(232, 92, 80, 127)), parent);
     new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(2, 92, 80, 125)), parent);

     doc->undoStack()->push(parent);
 }

 void MainWindow::about()
 {
     QMessageBox::about(this, tr("About Undo"), tr("The Undo demonstration shows how to use the Qt Undo framework."));
 }

 void MainWindow::aboutQt()
 {
     QMessageBox::aboutQt(this, tr("About Qt"));
 }
	/****************************************************************************
	**
	** Copyright (C) 2016 The Qt Company Ltd.
	** Contact: https://www.qt.io/licensing/
	**
	** This file is part of the demonstration applications of the Qt Toolkit.
	**
	** $QT_BEGIN_LICENSE:BSD$
	** 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.
	**
	** BSD License Usage
	** Alternatively, you may use this file under the terms of the BSD license
	** as follows:
	**
	** "Redistribution and use in source and binary forms, with or without
	** modification, are permitted provided that the following conditions are
	** met:
	** * Redistributions of source code must retain the above copyright
	** notice, this list of conditions and the following disclaimer.
	** * Redistributions in binary form must reproduce the above copyright
	** notice, this list of conditions and the following disclaimer in
	** the documentation and/or other materials provided with the
	** distribution.
	** * Neither the name of The Qt Company Ltd nor the names of its
	** contributors may be used to endorse or promote products derived
	** from this software without specific prior written permission.
	**
	**
	** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
	** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
	** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
	** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
	** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
	** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
	** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
	** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
	** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
	** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
	** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
	**
	** $QT_END_LICENSE$
	**
	****************************************************************************/

	#include "mainwindow.h"
	#include "document.h"
	#include "commands.h"

	#include <QUndoGroup>
	#include <QUndoStack>
	#include <QFileDialog>
	#include <QMessageBox>
	#include <QRandomGenerator>
	#include <QTextStream>
	#include <QToolButton>

	MainWindow::MainWindow(QWidget *parent)
	: QMainWindow(parent)
	{
	setupUi(this);

	QWidget *w = documentTabs->widget(0);
	documentTabs->removeTab(0);
	delete w;

	connect(actionOpen, &QAction::triggered, this, &MainWindow::openDocument);
	connect(actionClose, &QAction::triggered, this, &MainWindow::closeDocument);
	connect(actionNew, &QAction::triggered, this, &MainWindow::newDocument);
	connect(actionSave, &QAction::triggered, this, &MainWindow::saveDocument);
	connect(actionExit, &QAction::triggered, this, &QWidget::close);
	connect(actionRed, &QAction::triggered, this, &MainWindow::setShapeColor);
	connect(actionGreen, &QAction::triggered, this, &MainWindow::setShapeColor);
	connect(actionBlue, &QAction::triggered, this, &MainWindow::setShapeColor);
	connect(actionAddCircle, &QAction::triggered, this, &MainWindow::addShape);
	connect(actionAddRectangle, &QAction::triggered, this, &MainWindow::addShape);
	connect(actionAddTriangle, &QAction::triggered, this, &MainWindow::addShape);
	connect(actionRemoveShape, &QAction::triggered, this, &MainWindow::removeShape);
	connect(actionAddRobot, &QAction::triggered, this, &MainWindow::addRobot);
	connect(actionAddSnowman, &QAction::triggered, this, &MainWindow::addSnowman);
	connect(actionAbout, &QAction::triggered, this, &MainWindow::about);
	connect(actionAboutQt, &QAction::triggered, this, &MainWindow::aboutQt);

	connect(undoLimit, QOverload<int>::of(&QSpinBox::valueChanged), this, &MainWindow::updateActions);
	connect(documentTabs, &QTabWidget::currentChanged, this, &MainWindow::updateActions);

	actionOpen->setShortcut(QString("Ctrl+O"));
	actionClose->setShortcut(QString("Ctrl+W"));
	actionNew->setShortcut(QString("Ctrl+N"));
	actionSave->setShortcut(QString("Ctrl+S"));
	actionExit->setShortcut(QString("Ctrl+Q"));
	actionRemoveShape->setShortcut(QString("Del"));
	actionRed->setShortcut(QString("Alt+R"));
	actionGreen->setShortcut(QString("Alt+G"));
	actionBlue->setShortcut(QString("Alt+B"));
	actionAddCircle->setShortcut(QString("Alt+C"));
	actionAddRectangle->setShortcut(QString("Alt+L"));
	actionAddTriangle->setShortcut(QString("Alt+T"));

	m_undoGroup = new QUndoGroup(this);
	undoView->setGroup(m_undoGroup);
	undoView->setCleanIcon(QIcon(":/icons/ok.png"));

	QAction *undoAction = m_undoGroup->createUndoAction(this);
	QAction *redoAction = m_undoGroup->createRedoAction(this);
	undoAction->setIcon(QIcon(":/icons/undo.png"));
	redoAction->setIcon(QIcon(":/icons/redo.png"));
	menuShape->insertAction(menuShape->actions().at(0), undoAction);
	menuShape->insertAction(undoAction, redoAction);

	toolBar->addAction(undoAction);
	toolBar->addAction(redoAction);

	newDocument();
	updateActions();
	};

	void MainWindow::updateActions()
	{
	Document *doc = currentDocument();
	m_undoGroup->setActiveStack(doc == nullptr ? nullptr : doc->undoStack());
	QString shapeName = doc == nullptr ? QString() : doc->currentShapeName();

	actionAddRobot->setEnabled(doc != nullptr);
	actionAddSnowman->setEnabled(doc != nullptr);
	actionAddCircle->setEnabled(doc != nullptr);
	actionAddRectangle->setEnabled(doc != nullptr);
	actionAddTriangle->setEnabled(doc != nullptr);
	actionClose->setEnabled(doc != nullptr);
	actionSave->setEnabled(doc != nullptr && !doc->undoStack()->isClean());
	undoLimit->setEnabled(doc != nullptr && doc->undoStack()->count() == 0);

	if (shapeName.isEmpty()) {
	actionRed->setEnabled(false);
	actionGreen->setEnabled(false);
	actionBlue->setEnabled(false);
	actionRemoveShape->setEnabled(false);
	} else {
	Shape shape = doc->shape(shapeName);
	actionRed->setEnabled(shape.color() != Qt::red);
	actionGreen->setEnabled(shape.color() != Qt::green);
	actionBlue->setEnabled(shape.color() != Qt::blue);
	actionRemoveShape->setEnabled(true);
	}

	if (doc != nullptr) {
	int index = documentTabs->indexOf(doc);
	Q_ASSERT(index != -1);
	static const QIcon unsavedIcon(":/icons/filesave.png");
	documentTabs->setTabIcon(index, doc->undoStack()->isClean() ? QIcon() : unsavedIcon);

	if (doc->undoStack()->count() == 0)
	doc->undoStack()->setUndoLimit(undoLimit->value());
	}
	}

	void MainWindow::openDocument()
	{
	QString fileName = QFileDialog::getOpenFileName(this);
	if (fileName.isEmpty())
	return;

	QFile file(fileName);
	if (!file.open(QIODevice::ReadOnly)) {
	QMessageBox::warning(this,
	tr("File error"),
	tr("Failed to open\n%1").arg(fileName));
	return;
	}
	QTextStream stream(&file);

	Document *doc = new Document();
	if (!doc->load(stream)) {
	QMessageBox::warning(this,
	tr("Parse error"),
	tr("Failed to parse\n%1").arg(fileName));
	delete doc;
	return;
	}

	doc->setFileName(fileName);
	addDocument(doc);
	}

	QString MainWindow::fixedWindowTitle(const Document *doc) const
	{
	QString title = doc->fileName();

	if (title.isEmpty())
	title = tr("Unnamed");
	else
	title = QFileInfo(title).fileName();

	QString result;

	for (int i = 0; ; ++i) {
	result = title;
	if (i > 0)
	result += QString::number(i);

	bool unique = true;
	for (int j = 0; j < documentTabs->count(); ++j) {
	const QWidget *widget = documentTabs->widget(j);
	if (widget == doc)
	continue;
	if (result == documentTabs->tabText(j)) {
	unique = false;
	break;
	}
	}

	if (unique)
	break;
	}

	return result;
	}

	void MainWindow::addDocument(Document *doc)
	{
	if (documentTabs->indexOf(doc) != -1)
	return;
	m_undoGroup->addStack(doc->undoStack());
	documentTabs->addTab(doc, fixedWindowTitle(doc));
	connect(doc, &Document::currentShapeChanged, this, &MainWindow::updateActions);
	connect(doc->undoStack(), &QUndoStack::indexChanged, this, &MainWindow::updateActions);
	connect(doc->undoStack(), &QUndoStack::cleanChanged, this, &MainWindow::updateActions);

	setCurrentDocument(doc);
	}

	void MainWindow::setCurrentDocument(Document *doc)
	{
	documentTabs->setCurrentWidget(doc);
	}

	Document *MainWindow::currentDocument() const
	{
	return qobject_cast<Document*>(documentTabs->currentWidget());
	}

	void MainWindow::removeDocument(Document *doc)
	{
	int index = documentTabs->indexOf(doc);
	if (index == -1)
	return;

	documentTabs->removeTab(index);
	m_undoGroup->removeStack(doc->undoStack());
	disconnect(doc, &Document::currentShapeChanged, this, &MainWindow::updateActions);
	disconnect(doc->undoStack(), &QUndoStack::indexChanged, this, &MainWindow::updateActions);
	disconnect(doc->undoStack(), &QUndoStack::cleanChanged, this, &MainWindow::updateActions);

	if (documentTabs->count() == 0) {
	newDocument();
	updateActions();
	}
	}

	void MainWindow::saveDocument()
	{
	Document *doc = currentDocument();
	if (doc == nullptr)
	return;

	for (;;) {
	QString fileName = doc->fileName();

	if (fileName.isEmpty())
	fileName = QFileDialog::getSaveFileName(this);
	if (fileName.isEmpty())
	break;

	QFile file(fileName);
	if (!file.open(QIODevice::WriteOnly)) {
	QMessageBox::warning(this,
	tr("File error"),
	tr("Failed to open\n%1").arg(fileName));
	doc->setFileName(QString());
	} else {
	QTextStream stream(&file);
	doc->save(stream);
	doc->setFileName(fileName);

	int index = documentTabs->indexOf(doc);
	Q_ASSERT(index != -1);
	documentTabs->setTabText(index, fixedWindowTitle(doc));

	break;
	}
	}
	}

	void MainWindow::closeDocument()
	{
	Document *doc = currentDocument();
	if (doc == nullptr)
	return;

	if (!doc->undoStack()->isClean()) {
	int button
	= QMessageBox::warning(this,
	tr("Unsaved changes"),
	tr("Would you like to save this document?"),
	QMessageBox::Yes, QMessageBox::No);
	if (button == QMessageBox::Yes)
	saveDocument();
	}

	removeDocument(doc);
	delete doc;
	}

	void MainWindow::newDocument()
	{
	addDocument(new Document());
	}

	static QColor randomColor()
	{
	int r = QRandomGenerator::global()->bounded(3);
	switch (r) {
	case 0:
	return Qt::red;
	case 1:
	return Qt::green;
	default:
	break;
	}
	return Qt::blue;
	}

	static QRect randomRect(const QSize &s)
	{
	QSize min = Shape::minSize;

	int left = qRound((s.width() - min.width()) * (QRandomGenerator::global()->bounded(1.0)));
	int top = qRound((s.height() - min.height()) * (QRandomGenerator::global()->bounded(1.0)));
	int width = qRound((s.width() - left - min.width()) * (QRandomGenerator::global()->bounded(1.0))) + min.width();
	int height = qRound((s.height() - top - min.height()) * (QRandomGenerator::global()->bounded(1.0))) + min.height();

	return QRect(left, top, width, height);
	}

	void MainWindow::addShape()
	{
	Document *doc = currentDocument();
	if (doc == nullptr)
	return;

	Shape::Type type;

	if (sender() == actionAddCircle)
	type = Shape::Circle;
	else if (sender() == actionAddRectangle)
	type = Shape::Rectangle;
	else if (sender() == actionAddTriangle)
	type = Shape::Triangle;
	else return;

	Shape newShape(type, randomColor(), randomRect(doc->size()));
	doc->undoStack()->push(new AddShapeCommand(doc, newShape));
	}

	void MainWindow::removeShape()
	{
	Document *doc = currentDocument();
	if (doc == nullptr)
	return;

	QString shapeName = doc->currentShapeName();
	if (shapeName.isEmpty())
	return;

	doc->undoStack()->push(new RemoveShapeCommand(doc, shapeName));
	}

	void MainWindow::setShapeColor()
	{
	Document *doc = currentDocument();
	if (doc == nullptr)
	return;

	QString shapeName = doc->currentShapeName();
	if (shapeName.isEmpty())
	return;

	QColor color;

	if (sender() == actionRed)
	color = Qt::red;
	else if (sender() == actionGreen)
	color = Qt::green;
	else if (sender() == actionBlue)
	color = Qt::blue;
	else
	return;

	if (color == doc->shape(shapeName).color())
	return;

	doc->undoStack()->push(new SetShapeColorCommand(doc, shapeName, color));
	}

	void MainWindow::addSnowman()
	{
	Document *doc = currentDocument();
	if (doc == nullptr)
	return;

	// Create a macro command using beginMacro() and endMacro()

	doc->undoStack()->beginMacro(tr("Add snowman"));
	doc->undoStack()->push(new AddShapeCommand(doc,
	Shape(Shape::Circle, Qt::blue, QRect(51, 30, 97, 95))));
	doc->undoStack()->push(new AddShapeCommand(doc,
	Shape(Shape::Circle, Qt::blue, QRect(27, 123, 150, 133))));
	doc->undoStack()->push(new AddShapeCommand(doc,
	Shape(Shape::Circle, Qt::blue, QRect(11, 253, 188, 146))));
	doc->undoStack()->endMacro();
	}

	void MainWindow::addRobot()
	{
	Document *doc = currentDocument();
	if (doc == nullptr)
	return;

	// Compose a macro command by explicitly adding children to a parent command

	QUndoCommand *parent = new QUndoCommand(tr("Add robot"));

	new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(115, 15, 81, 70)), parent);
	new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(82, 89, 148, 188)), parent);
	new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(76, 280, 80, 165)), parent);
	new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(163, 280, 80, 164)), parent);
	new AddShapeCommand(doc, Shape(Shape::Circle, Qt::blue, QRect(116, 25, 80, 50)), parent);
	new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(232, 92, 80, 127)), parent);
	new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(2, 92, 80, 125)), parent);

	doc->undoStack()->push(parent);
	}

	void MainWindow::about()
	{
	QMessageBox::about(this, tr("About Undo"), tr("The Undo demonstration shows how to use the Qt Undo framework."));
	}

	void MainWindow::aboutQt()
	{
	QMessageBox::aboutQt(this, tr("About Qt"));
	}