customproxy.cpp Example File

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 #include "customproxy.h"

 #include <QtWidgets>

 CustomProxy::CustomProxy(QGraphicsItem *parent, Qt::WindowFlags wFlags)
     : QGraphicsProxyWidget(parent, wFlags), popupShown(false), currentPopup(0)
 {
     timeLine = new QTimeLine(250, this);
     connect(timeLine, SIGNAL(valueChanged(qreal)),
             this, SLOT(updateStep(qreal)));
     connect(timeLine, SIGNAL(stateChanged(QTimeLine::State)),
             this, SLOT(stateChanged(QTimeLine::State)));
 }

 QRectF CustomProxy::boundingRect() const
 {
     return QGraphicsProxyWidget::boundingRect().adjusted(0, 0, 10, 10);
 }

 void CustomProxy::paintWindowFrame(QPainter *painter, const QStyleOptionGraphicsItem *option,
                                    QWidget *widget)
 {
     const QColor color(0, 0, 0, 64);

     QRectF r = windowFrameRect();
     QRectF right(r.right(), r.top() + 10, 10, r.height() - 10);
     QRectF bottom(r.left() + 10, r.bottom(), r.width(), 10);
     bool intersectsRight = right.intersects(option->exposedRect);
     bool intersectsBottom = bottom.intersects(option->exposedRect);
     if (intersectsRight && intersectsBottom) {
         QPainterPath path;
         path.addRect(right);
         path.addRect(bottom);
         painter->setPen(Qt::NoPen);
         painter->setBrush(color);
         painter->drawPath(path);
     } else if (intersectsBottom) {
         painter->fillRect(bottom, color);
     } else if (intersectsRight) {
         painter->fillRect(right, color);
     }

     QGraphicsProxyWidget::paintWindowFrame(painter, option, widget);
 }

 void CustomProxy::hoverEnterEvent(QGraphicsSceneHoverEvent *event)
 {
     QGraphicsProxyWidget::hoverEnterEvent(event);
     scene()->setActiveWindow(this);
     if (timeLine->currentValue() != 1)
         zoomIn();
 }

 void CustomProxy::hoverLeaveEvent(QGraphicsSceneHoverEvent *event)
 {
     QGraphicsProxyWidget::hoverLeaveEvent(event);
     if (!popupShown && (timeLine->direction() != QTimeLine::Backward || timeLine->currentValue() != 0))
         zoomOut();
 }

 bool CustomProxy::sceneEventFilter(QGraphicsItem *watched, QEvent *event)
 {
     if (watched->isWindow() && (event->type() == QEvent::UngrabMouse || event->type() == QEvent::GrabMouse)) {
         popupShown = watched->isVisible();
         if (!popupShown && !isUnderMouse())
             zoomOut();
     }
     return QGraphicsProxyWidget::sceneEventFilter(watched, event);
 }

 QVariant CustomProxy::itemChange(GraphicsItemChange change, const QVariant &value)
 {
     if (change == ItemChildAddedChange || change == ItemChildRemovedChange) {
         if (change == ItemChildAddedChange) {
             currentPopup = qvariant_cast<QGraphicsItem *>(value);
             currentPopup->setCacheMode(ItemCoordinateCache);
             if (scene())
                 currentPopup->installSceneEventFilter(this);
         } else if (scene()) {
             currentPopup->removeSceneEventFilter(this);
             currentPopup = 0;
         }
     } else if (currentPopup && change == ItemSceneHasChanged) {
         currentPopup->installSceneEventFilter(this);
     }
     return QGraphicsProxyWidget::itemChange(change, value);
 }

 void CustomProxy::updateStep(qreal step)
 {
     QRectF r = boundingRect();
     setTransform(QTransform()
                  .translate(r.width() / 2, r.height() / 2)
                  .rotate(step * 30, Qt::XAxis)
                  .rotate(step * 10, Qt::YAxis)
                  .rotate(step * 5, Qt::ZAxis)
                  .scale(1 + 1.5 * step, 1 + 1.5 * step)
                  .translate(-r.width() / 2, -r.height() / 2));
 }

 void CustomProxy::stateChanged(QTimeLine::State state)
 {
     if (state == QTimeLine::Running) {
         if (timeLine->direction() == QTimeLine::Forward)
             setCacheMode(ItemCoordinateCache);
     } else if (state == QTimeLine::NotRunning) {
         if (timeLine->direction() == QTimeLine::Backward)
             setCacheMode(DeviceCoordinateCache);
     }
 }

 void CustomProxy::zoomIn()
 {
     if (timeLine->direction() != QTimeLine::Forward)
         timeLine->setDirection(QTimeLine::Forward);
     if (timeLine->state() == QTimeLine::NotRunning)
         timeLine->start();
 }

 void CustomProxy::zoomOut()
 {
     if (timeLine->direction() != QTimeLine::Backward)
         timeLine->setDirection(QTimeLine::Backward);
     if (timeLine->state() == QTimeLine::NotRunning)
         timeLine->start();
 }