mainwindow.cpp Example File
graphicsview/diagramscene/mainwindow.cpp

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 #include <QtGui>
 #include <QLabel>

 #include "mainwindow.h"
 #include "diagramitem.h"
 #include "diagramscene.h"
 #include "diagramtextitem.h"

 const int InsertTextButton = 10;

 MainWindow::MainWindow()
 {
     createActions();
     createToolBox();
     createMenus();

     scene = new DiagramScene(itemMenu);
     scene->setSceneRect(QRectF(0, 0, 5000, 5000));
     connect(scene, SIGNAL(itemInserted(DiagramItem*)),
             this, SLOT(itemInserted(DiagramItem*)));
     connect(scene, SIGNAL(textInserted(QGraphicsTextItem*)),
         this, SLOT(textInserted(QGraphicsTextItem*)));
     connect(scene, SIGNAL(itemSelected(QGraphicsItem*)),
         this, SLOT(itemSelected(QGraphicsItem*)));
     createToolbars();

     QHBoxLayout *layout = new QHBoxLayout;
     layout->addWidget(toolBox);
     view = new QGraphicsView(scene);
     layout->addWidget(view);

     QWidget *widget = new QWidget;
     widget->setLayout(layout);

     setCentralWidget(widget);
     setWindowTitle(tr("Diagramscene"));
     setUnifiedTitleAndToolBarOnMac(true);
 }

 void MainWindow::backgroundButtonGroupClicked(QAbstractButton *button)
 {
     QList<QAbstractButton *> buttons = backgroundButtonGroup->buttons();
     foreach (QAbstractButton *myButton, buttons) {
     if (myButton != button)
         button->setChecked(false);
     }
     QString text = button->text();
     if (text == tr("Blue Grid"))
         scene->setBackgroundBrush(QPixmap(":/images/background1.png"));
     else if (text == tr("White Grid"))
         scene->setBackgroundBrush(QPixmap(":/images/background2.png"));
     else if (text == tr("Gray Grid"))
         scene->setBackgroundBrush(QPixmap(":/images/background3.png"));
     else
         scene->setBackgroundBrush(QPixmap(":/images/background4.png"));

     scene->update();
     view->update();
 }

 void MainWindow::buttonGroupClicked(int id)
 {
     QList<QAbstractButton *> buttons = buttonGroup->buttons();
     foreach (QAbstractButton *button, buttons) {
     if (buttonGroup->button(id) != button)
         button->setChecked(false);
     }
     if (id == InsertTextButton) {
         scene->setMode(DiagramScene::InsertText);
     } else {
         scene->setItemType(DiagramItem::DiagramType(id));
         scene->setMode(DiagramScene::InsertItem);
     }
 }

 void MainWindow::deleteItem()
 {
     foreach (QGraphicsItem *item, scene->selectedItems()) {
         if (item->type() == DiagramItem::Type) {
             qgraphicsitem_cast<DiagramItem *>(item)->removeArrows();
         }
         scene->removeItem(item);
     }
 }

 void MainWindow::pointerGroupClicked(int)
 {
     scene->setMode(DiagramScene::Mode(pointerTypeGroup->checkedId()));
 }

 void MainWindow::bringToFront()
 {
     if (scene->selectedItems().isEmpty())
         return;

     QGraphicsItem *selectedItem = scene->selectedItems().first();
     QList<QGraphicsItem *> overlapItems = selectedItem->collidingItems();

     qreal zValue = 0;
     foreach (QGraphicsItem *item, overlapItems) {
         if (item->zValue() >= zValue &&
             item->type() == DiagramItem::Type)
             zValue = item->zValue() + 0.1;
     }
     selectedItem->setZValue(zValue);
 }

 void MainWindow::sendToBack()
 {
     if (scene->selectedItems().isEmpty())
         return;

     QGraphicsItem *selectedItem = scene->selectedItems().first();
     QList<QGraphicsItem *> overlapItems = selectedItem->collidingItems();

     qreal zValue = 0;
     foreach (QGraphicsItem *item, overlapItems) {
         if (item->zValue() <= zValue &&
             item->type() == DiagramItem::Type)
             zValue = item->zValue() - 0.1;
     }
     selectedItem->setZValue(zValue);
 }

 void MainWindow::itemInserted(DiagramItem *item)
 {
     pointerTypeGroup->button(int(DiagramScene::MoveItem))->setChecked(true);
     scene->setMode(DiagramScene::Mode(pointerTypeGroup->checkedId()));
     buttonGroup->button(int(item->diagramType()))->setChecked(false);
 }

 void MainWindow::textInserted(QGraphicsTextItem *)
 {
     buttonGroup->button(InsertTextButton)->setChecked(false);
     scene->setMode(DiagramScene::Mode(pointerTypeGroup->checkedId()));
 }

 void MainWindow::currentFontChanged(const QFont &)
 {
     handleFontChange();
 }

 void MainWindow::fontSizeChanged(const QString &)
 {
     handleFontChange();
 }

 void MainWindow::sceneScaleChanged(const QString &scale)
 {
     double newScale = scale.left(scale.indexOf(tr("%"))).toDouble() / 100.0;
     QMatrix oldMatrix = view->matrix();
     view->resetMatrix();
     view->translate(oldMatrix.dx(), oldMatrix.dy());
     view->scale(newScale, newScale);
 }

 void MainWindow::textColorChanged()
 {
     textAction = qobject_cast<QAction *>(sender());
     fontColorToolButton->setIcon(createColorToolButtonIcon(
                 ":/images/textpointer.png",
                 qVariantValue<QColor>(textAction->data())));
     textButtonTriggered();
 }

 void MainWindow::itemColorChanged()
 {
     fillAction = qobject_cast<QAction *>(sender());
     fillColorToolButton->setIcon(createColorToolButtonIcon(
                  ":/images/floodfill.png",
                  qVariantValue<QColor>(fillAction->data())));
     fillButtonTriggered();
 }

 void MainWindow::lineColorChanged()
 {
     lineAction = qobject_cast<QAction *>(sender());
     lineColorToolButton->setIcon(createColorToolButtonIcon(
                  ":/images/linecolor.png",
                  qVariantValue<QColor>(lineAction->data())));
     lineButtonTriggered();
 }

 void MainWindow::textButtonTriggered()
 {
     scene->setTextColor(qVariantValue<QColor>(textAction->data()));
 }

 void MainWindow::fillButtonTriggered()
 {
     scene->setItemColor(qVariantValue<QColor>(fillAction->data()));
 }

 void MainWindow::lineButtonTriggered()
 {
     scene->setLineColor(qVariantValue<QColor>(lineAction->data()));
 }

 void MainWindow::handleFontChange()
 {
     QFont font = fontCombo->currentFont();
     font.setPointSize(fontSizeCombo->currentText().toInt());
     font.setWeight(boldAction->isChecked() ? QFont::Bold : QFont::Normal);
     font.setItalic(italicAction->isChecked());
     font.setUnderline(underlineAction->isChecked());

     scene->setFont(font);
 }

 void MainWindow::itemSelected(QGraphicsItem *item)
 {
     DiagramTextItem *textItem =
     qgraphicsitem_cast<DiagramTextItem *>(item);

     QFont font = textItem->font();
     QColor color = textItem->defaultTextColor();
     fontCombo->setCurrentFont(font);
     fontSizeCombo->setEditText(QString().setNum(font.pointSize()));
     boldAction->setChecked(font.weight() == QFont::Bold);
     italicAction->setChecked(font.italic());
     underlineAction->setChecked(font.underline());
 }

 void MainWindow::about()
 {
     QMessageBox::about(this, tr("About Diagram Scene"),
                        tr("The <b>Diagram Scene</b> example shows "
                           "use of the graphics framework."));
 }

 void MainWindow::createToolBox()
 {
     buttonGroup = new QButtonGroup;
     buttonGroup->setExclusive(false);
     connect(buttonGroup, SIGNAL(buttonClicked(int)),
             this, SLOT(buttonGroupClicked(int)));
     QGridLayout *layout = new QGridLayout;
     layout->addWidget(createCellWidget(tr("Conditional"),
                                DiagramItem::Conditional), 0, 0);
     layout->addWidget(createCellWidget(tr("Process"),
                       DiagramItem::Step),0, 1);
     layout->addWidget(createCellWidget(tr("Input/Output"),
                       DiagramItem::Io), 1, 0);

     QToolButton *textButton = new QToolButton;
     textButton->setCheckable(true);
     buttonGroup->addButton(textButton, InsertTextButton);
     textButton->setIcon(QIcon(QPixmap(":/images/textpointer.png")
                         .scaled(30, 30)));
     textButton->setIconSize(QSize(50, 50));
     QGridLayout *textLayout = new QGridLayout;
     textLayout->addWidget(textButton, 0, 0, Qt::AlignHCenter);
     textLayout->addWidget(new QLabel(tr("Text")), 1, 0, Qt::AlignCenter);
     QWidget *textWidget = new QWidget;
     textWidget->setLayout(textLayout);
     layout->addWidget(textWidget, 1, 1);

     layout->setRowStretch(3, 10);
     layout->setColumnStretch(2, 10);

     QWidget *itemWidget = new QWidget;
     itemWidget->setLayout(layout);

     backgroundButtonGroup = new QButtonGroup;
     connect(backgroundButtonGroup, SIGNAL(buttonClicked(QAbstractButton*)),
             this, SLOT(backgroundButtonGroupClicked(QAbstractButton*)));

     QGridLayout *backgroundLayout = new QGridLayout;
     backgroundLayout->addWidget(createBackgroundCellWidget(tr("Blue Grid"),
                 ":/images/background1.png"), 0, 0);
     backgroundLayout->addWidget(createBackgroundCellWidget(tr("White Grid"),
                 ":/images/background2.png"), 0, 1);
     backgroundLayout->addWidget(createBackgroundCellWidget(tr("Gray Grid"),
                     ":/images/background3.png"), 1, 0);
     backgroundLayout->addWidget(createBackgroundCellWidget(tr("No Grid"),
                 ":/images/background4.png"), 1, 1);

     backgroundLayout->setRowStretch(2, 10);
     backgroundLayout->setColumnStretch(2, 10);

     QWidget *backgroundWidget = new QWidget;
     backgroundWidget->setLayout(backgroundLayout);

     toolBox = new QToolBox;
     toolBox->setSizePolicy(QSizePolicy(QSizePolicy::Maximum, QSizePolicy::Ignored));
     toolBox->setMinimumWidth(itemWidget->sizeHint().width());
     toolBox->addItem(itemWidget, tr("Basic Flowchart Shapes"));
     toolBox->addItem(backgroundWidget, tr("Backgrounds"));
 }

 void MainWindow::createActions()
 {
     toFrontAction = new QAction(QIcon(":/images/bringtofront.png"),
                                 tr("Bring to &Front"), this);
     toFrontAction->setShortcut(tr("Ctrl+F"));
     toFrontAction->setStatusTip(tr("Bring item to front"));
     connect(toFrontAction, SIGNAL(triggered()),
             this, SLOT(bringToFront()));

     sendBackAction = new QAction(QIcon(":/images/sendtoback.png"),
                                  tr("Send to &Back"), this);
     sendBackAction->setShortcut(tr("Ctrl+B"));
     sendBackAction->setStatusTip(tr("Send item to back"));
     connect(sendBackAction, SIGNAL(triggered()),
         this, SLOT(sendToBack()));

     deleteAction = new QAction(QIcon(":/images/delete.png"),
                                tr("&Delete"), this);
     deleteAction->setShortcut(tr("Delete"));
     deleteAction->setStatusTip(tr("Delete item from diagram"));
     connect(deleteAction, SIGNAL(triggered()),
         this, SLOT(deleteItem()));

     exitAction = new QAction(tr("E&xit"), this);
     exitAction->setShortcuts(QKeySequence::Quit);
     exitAction->setStatusTip(tr("Quit Scenediagram example"));
     connect(exitAction, SIGNAL(triggered()), this, SLOT(close()));

     boldAction = new QAction(tr("Bold"), this);
     boldAction->setCheckable(true);
     QPixmap pixmap(":/images/bold.png");
     boldAction->setIcon(QIcon(pixmap));
     boldAction->setShortcut(tr("Ctrl+B"));
     connect(boldAction, SIGNAL(triggered()),
             this, SLOT(handleFontChange()));

     italicAction = new QAction(QIcon(":/images/italic.png"),
                                tr("Italic"), this);
     italicAction->setCheckable(true);
     italicAction->setShortcut(tr("Ctrl+I"));
     connect(italicAction, SIGNAL(triggered()),
             this, SLOT(handleFontChange()));

     underlineAction = new QAction(QIcon(":/images/underline.png"),
                                   tr("Underline"), this);
     underlineAction->setCheckable(true);
     underlineAction->setShortcut(tr("Ctrl+U"));
     connect(underlineAction, SIGNAL(triggered()),
             this, SLOT(handleFontChange()));

     aboutAction = new QAction(tr("A&bout"), this);
     aboutAction->setShortcut(tr("Ctrl+B"));
     connect(aboutAction, SIGNAL(triggered()),
             this, SLOT(about()));
 }

 void MainWindow::createMenus()
 {
     fileMenu = menuBar()->addMenu(tr("&File"));
     fileMenu->addAction(exitAction);

     itemMenu = menuBar()->addMenu(tr("&Item"));
     itemMenu->addAction(deleteAction);
     itemMenu->addSeparator();
     itemMenu->addAction(toFrontAction);
     itemMenu->addAction(sendBackAction);

     aboutMenu = menuBar()->addMenu(tr("&Help"));
     aboutMenu->addAction(aboutAction);
 }

 void MainWindow::createToolbars()
 {
     editToolBar = addToolBar(tr("Edit"));
     editToolBar->addAction(deleteAction);
     editToolBar->addAction(toFrontAction);
     editToolBar->addAction(sendBackAction);

     fontCombo = new QFontComboBox();
     fontSizeCombo = new QComboBox();
     connect(fontCombo, SIGNAL(currentFontChanged(QFont)),
             this, SLOT(currentFontChanged(QFont)));

     fontSizeCombo = new QComboBox;
     fontSizeCombo->setEditable(true);
     for (int i = 8; i < 30; i = i + 2)
         fontSizeCombo->addItem(QString().setNum(i));
     QIntValidator *validator = new QIntValidator(2, 64, this);
     fontSizeCombo->setValidator(validator);
     connect(fontSizeCombo, SIGNAL(currentIndexChanged(QString)),
             this, SLOT(fontSizeChanged(QString)));

     fontColorToolButton = new QToolButton;
     fontColorToolButton->setPopupMode(QToolButton::MenuButtonPopup);
     fontColorToolButton->setMenu(createColorMenu(SLOT(textColorChanged()),
                                                  Qt::black));
     textAction = fontColorToolButton->menu()->defaultAction();
     fontColorToolButton->setIcon(createColorToolButtonIcon(
     ":/images/textpointer.png", Qt::black));
     fontColorToolButton->setAutoFillBackground(true);
     connect(fontColorToolButton, SIGNAL(clicked()),
             this, SLOT(textButtonTriggered()));

     fillColorToolButton = new QToolButton;
     fillColorToolButton->setPopupMode(QToolButton::MenuButtonPopup);
     fillColorToolButton->setMenu(createColorMenu(SLOT(itemColorChanged()),
                          Qt::white));
     fillAction = fillColorToolButton->menu()->defaultAction();
     fillColorToolButton->setIcon(createColorToolButtonIcon(
     ":/images/floodfill.png", Qt::white));
     connect(fillColorToolButton, SIGNAL(clicked()),
             this, SLOT(fillButtonTriggered()));

     lineColorToolButton = new QToolButton;
     lineColorToolButton->setPopupMode(QToolButton::MenuButtonPopup);
     lineColorToolButton->setMenu(createColorMenu(SLOT(lineColorChanged()),
                                  Qt::black));
     lineAction = lineColorToolButton->menu()->defaultAction();
     lineColorToolButton->setIcon(createColorToolButtonIcon(
         ":/images/linecolor.png", Qt::black));
     connect(lineColorToolButton, SIGNAL(clicked()),
             this, SLOT(lineButtonTriggered()));

     textToolBar = addToolBar(tr("Font"));
     textToolBar->addWidget(fontCombo);
     textToolBar->addWidget(fontSizeCombo);
     textToolBar->addAction(boldAction);
     textToolBar->addAction(italicAction);
     textToolBar->addAction(underlineAction);

     colorToolBar = addToolBar(tr("Color"));
     colorToolBar->addWidget(fontColorToolButton);
     colorToolBar->addWidget(fillColorToolButton);
     colorToolBar->addWidget(lineColorToolButton);

     QToolButton *pointerButton = new QToolButton;
     pointerButton->setCheckable(true);
     pointerButton->setChecked(true);
     pointerButton->setIcon(QIcon(":/images/pointer.png"));
     QToolButton *linePointerButton = new QToolButton;
     linePointerButton->setCheckable(true);
     linePointerButton->setIcon(QIcon(":/images/linepointer.png"));

     pointerTypeGroup = new QButtonGroup;
     pointerTypeGroup->addButton(pointerButton, int(DiagramScene::MoveItem));
     pointerTypeGroup->addButton(linePointerButton,
                                 int(DiagramScene::InsertLine));
     connect(pointerTypeGroup, SIGNAL(buttonClicked(int)),
             this, SLOT(pointerGroupClicked(int)));

     sceneScaleCombo = new QComboBox;
     QStringList scales;
     scales << tr("50%") << tr("75%") << tr("100%") << tr("125%") << tr("150%");
     sceneScaleCombo->addItems(scales);
     sceneScaleCombo->setCurrentIndex(2);
     connect(sceneScaleCombo, SIGNAL(currentIndexChanged(QString)),
             this, SLOT(sceneScaleChanged(QString)));

     pointerToolbar = addToolBar(tr("Pointer type"));
     pointerToolbar->addWidget(pointerButton);
     pointerToolbar->addWidget(linePointerButton);
     pointerToolbar->addWidget(sceneScaleCombo);
 }

 QWidget *MainWindow::createBackgroundCellWidget(const QString &text,
                         const QString &image)
 {
     QToolButton *button = new QToolButton;
     button->setText(text);
     button->setIcon(QIcon(image));
     button->setIconSize(QSize(50, 50));
     button->setCheckable(true);
     backgroundButtonGroup->addButton(button);

     QGridLayout *layout = new QGridLayout;
     layout->addWidget(button, 0, 0, Qt::AlignHCenter);
     layout->addWidget(new QLabel(text), 1, 0, Qt::AlignCenter);

     QWidget *widget = new QWidget;
     widget->setLayout(layout);

     return widget;
 }

 QWidget *MainWindow::createCellWidget(const QString &text,
                       DiagramItem::DiagramType type)
 {

     DiagramItem item(type, itemMenu);
     QIcon icon(item.image());

     QToolButton *button = new QToolButton;
     button->setIcon(icon);
     button->setIconSize(QSize(50, 50));
     button->setCheckable(true);
     buttonGroup->addButton(button, int(type));

     QGridLayout *layout = new QGridLayout;
     layout->addWidget(button, 0, 0, Qt::AlignHCenter);
     layout->addWidget(new QLabel(text), 1, 0, Qt::AlignCenter);

     QWidget *widget = new QWidget;
     widget->setLayout(layout);

     return widget;
 }

 QMenu *MainWindow::createColorMenu(const char *slot, QColor defaultColor)
 {
     QList<QColor> colors;
     colors << Qt::black << Qt::white << Qt::red << Qt::blue << Qt::yellow;
     QStringList names;
     names << tr("black") << tr("white") << tr("red") << tr("blue")
           << tr("yellow");

     QMenu *colorMenu = new QMenu;
     for (int i = 0; i < colors.count(); ++i) {
         QAction *action = new QAction(names.at(i), this);
         action->setData(colors.at(i));
         action->setIcon(createColorIcon(colors.at(i)));
         connect(action, SIGNAL(triggered()),
                 this, slot);
         colorMenu->addAction(action);
         if (colors.at(i) == defaultColor) {
             colorMenu->setDefaultAction(action);
         }
     }
     return colorMenu;
 }

 QIcon MainWindow::createColorToolButtonIcon(const QString &imageFile,
                         QColor color)
 {
     QPixmap pixmap(50, 80);
     pixmap.fill(Qt::transparent);
     QPainter painter(&pixmap);
     QPixmap image(imageFile);
     QRect target(0, 0, 50, 60);
     QRect source(0, 0, 42, 42);
     painter.fillRect(QRect(0, 60, 50, 80), color);
     painter.drawPixmap(target, image, source);

     return QIcon(pixmap);
 }

 QIcon MainWindow::createColorIcon(QColor color)
 {
     QPixmap pixmap(20, 20);
     QPainter painter(&pixmap);
     painter.setPen(Qt::NoPen);
     painter.fillRect(QRect(0, 0, 20, 20), color);

     return QIcon(pixmap);
 }