[Qt-interest] Grabbing the mouse

[phil prentice]

Hi
  I've got a widget derived from QGraphicsView
The first time a user presses the mouse I grab the mouse and store the first 
set of coordinates(of a line).
I then move the cursor around and select the second coordinate of the line 
(which can be outsoide of the window).  This in turn was going to release the 
mouse.  Unfortunately the application completely locks the user out.  The 
mouse no longer works for any widget including the one that grabbed it.
Please see code below. Its probably obviuos but what am I doing wrong??

Thanks for your help
Phil


// VIRTUAL
void myQGraphicsView::mousePressEvent(QMouseEvent *event)
{
  qDebug("Mouse press event = %d,%d",event->x(), event->y() );
  qDebug("Mouse press event = %d,%d",event->globalX(), event->globalY() );
  QPointF pt = mapToScene(event->x(), event->y());
  qDebug("Mouse scenepress event = %E,%E", pt.x(), pt.y());

  if(m_GraphicsItem)
  {
    qDebug("Before release");
    releaseMouse();
    qDebug("After release");
    QGraphicsLineItem *line = static_cast<QGraphicsLineItem 
*>(m_GraphicsItem);
    QPen pen(QColor(mainwindow_ui::penColour));
    line->setPen(pen);
    line->setLine(m_pt1x, m_pt1y,  pt.x(), pt.y());
    scene()->addItem(m_GraphicsItem);
    m_GraphicsItem = NULL;
  }
  else
  {
    grabMouse(Qt::CrossCursor);
    m_GraphicsItem = new QGraphicsLineItem;
    m_pt1x =  pt.x();
    m_pt1y =  pt.y();
  }
  event->accept();
}