customproxy.cpp Example File

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  #include "customproxy.h"

  #include <QStyleOptionGraphicsItem>
  #include <QPainter>
  #include <QGraphicsScene>

  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();
  }