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# mainwindow.cpp Example File

graphicsview/diagramscene/mainwindow.cpp

     /****************************************************************************
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     ** This file is part of the examples of the Qt Toolkit.
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     #include <QtGui>
     #include <QLabel>

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

     const int InsertTextButton = 10;

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

         scene = new DiagramScene(itemMenu, this);
         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)
                 myButton->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() == Arrow::Type) {
                 scene->removeItem(item);
                 Arrow *arrow = qgraphicsitem_cast<Arrow *>(item);
                 arrow->startItem()->removeArrow(arrow);
                 arrow->endItem()->removeArrow(arrow);
                 delete item;
             }
         }

         foreach (QGraphicsItem *item, scene->selectedItems()) {
              if (item->type() == DiagramItem::Type) {
                  qgraphicsitem_cast<DiagramItem *>(item)->removeArrows();
              }
              scene->removeItem(item);
              delete 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",
                     qvariant_cast<QColor>(textAction->data())));
         textButtonTriggered();
     }

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

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

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

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

     void MainWindow::lineButtonTriggered()
     {
         scene->setLineColor(qvariant_cast<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(this);
         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(this);
         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();
         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(this);
         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(this);
         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);
     }