QGraphicsView scroll problem or retained image on screen
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Please Help me!!! And sorry about my poor English.
I add QGraphicsRectItem in QGraphicsScene, and set very large SceneRect. QGraphicsView show scroller up.
When mouse press , move on QGraphicsScene, I will do QGraphicsRectItem->setRect() .
When mouse release will hide QGraphicsRectItem.
when I move mouse and scroller , some time mouse release will have some retained image on QGraphicsViewmy code:
@
ggraphicsView::ggraphicsView(QWidget *parent):
QGraphicsView(parent){
m_qGraphicsScene = new QGraphicsScene;
setScene(m_qGraphicsScene);
//selection box
m_pGRecItemSelectionBox=new QGraphicsRectItem();
m_qGraphicsScene->addItem(m_pGRecItemSelectionBox);
m_qGraphicsScene->setSceneRect(QRectF(0,0, 600,1000));
}void ggraphicsView::mousePressEvent( QMouseEvent* event)
{
m_ptStartPoint = mapToScene(event->pos());
m_pGRecItemSelectionBox->setRect(QRectF(m_ptStartPoint, QSize()));
m_pGRecItemSelectionBox->show();
}void ggraphicsView::mouseMoveEvent (QMouseEvent* event)
{
m_ptMovePoint = mapToScene(event->pos());
m_pGRecItemSelectionBox->setRect(QRectF(m_ptStartPoint, m_ptMovePoint).normalized());
m_pGRecItemSelectionBox->setBrush(QBrush(QColor(128, 128, 255, 100),Qt::SolidPattern));
m_pGRecItemSelectionBox->setPen(QPen(Qt::NoPen));}
void ggraphicsView::mouseReleaseEvent( QMouseEvent* event)
{
m_pGRecItemSelectionBox->hide();
}
@problem: retained image ,when mouse move & wheel together.
!http://i.imgur.com/HMk8nLY.png?1(retained image)![edit: added missing coding tags @ SGaist]
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it is weird, i answer my question.
this quest I try to do QRubberBand.
mouse press and move show a Rectangle, mouse release will disappear.It is about viewport update. if someone have same problem, u can see QGraphicsView::ViewportUpdateMode.