view.cpp Example File

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 #include "informationwindow.h"
 #include "imageitem.h"
 #include "view.h"

 View::View(const QString &items, const QString &images, QWidget *parent)
     : QGraphicsView(parent)
 {
     itemTable = new QSqlRelationalTableModel(this);
     itemTable->setTable(items);
     itemTable->setRelation(1, QSqlRelation(images, "itemid", "file"));
     itemTable->select();

     scene = new QGraphicsScene(this);
     scene->setSceneRect(0, 0, 465, 365);
     setScene(scene);

     addItems();

     setMinimumSize(470, 370);
     setMaximumSize(470, 370);

     QLinearGradient gradient(QPointF(0, 0), QPointF(0, 370));
     gradient.setColorAt(0, QColor("#868482"));
     gradient.setColorAt(1, QColor("#5d5b59"));
     setBackgroundBrush(gradient);
 }

 void View::addItems()
 {
     int itemCount = itemTable->rowCount();

     int imageOffset = 150;
     int leftMargin = 70;
     int topMargin = 40;

     for (int i = 0; i < itemCount; i++) {
         QSqlRecord record = itemTable->record(i);

         int id = record.value("id").toInt();
         QString file = record.value("file").toString();
         QString item = record.value("itemtype").toString();

         int columnOffset = ((i % 2) * 37);
         int x = ((i % 2) * imageOffset) + leftMargin + columnOffset;
         int y = ((i / 2) * imageOffset) + topMargin;

         ImageItem *image = new ImageItem(id, QPixmap(":/" + file));
         image->setData(0, i);
         image->setPos(x, y);
         scene->addItem(image);

         QGraphicsTextItem *label = scene->addText(item);
         label->setDefaultTextColor(QColor("#d7d6d5"));
         QPointF labelOffset((120 - label->boundingRect().width()) / 2, 120.0);
         label->setPos(QPointF(x, y) + labelOffset);
     }
 }

 void View::mouseReleaseEvent(QMouseEvent *event)
 {
     if (QGraphicsItem *item = itemAt(event->pos())) {
         if (ImageItem *image = qgraphicsitem_cast<ImageItem *>(item))
             showInformation(image);
     }
     QGraphicsView::mouseReleaseEvent(event);
 }

 void View::showInformation(ImageItem *image)
 {
     int id = image->id();
     if (id < 0 || id >= itemTable->rowCount())
         return;

     InformationWindow *window = findWindow(id);
     if (!window) {
         window = new InformationWindow(id, itemTable, this);

         connect(window, QOverload<int,const QString &>::of(&InformationWindow::imageChanged),
                 this, QOverload<int,const QString &>::of(&View::updateImage));

         window->move(pos() + QPoint(20, 40));
         window->show();
         informationWindows.append(window);
     }

     if (window->isVisible()) {
         window->raise();
         window->activateWindow();
     } else
         window->show();
 }

 void View::updateImage(int id, const QString &fileName)
 {
     QList<QGraphicsItem *> items = scene->items();

     while(!items.empty()) {
         QGraphicsItem *item = items.takeFirst();

         if (ImageItem *image = qgraphicsitem_cast<ImageItem *>(item)) {
             if (image->id() == id){
                 image->setPixmap(QPixmap(":/" +fileName));
                 image->adjust();
                 break;
             }
         }
     }
 }

 InformationWindow *View::findWindow(int id) const
 {
     for (auto window : informationWindows) {
         if (window && (window->id() == id))
             return window;
     }
     return nullptr;
 }