Facing problem with Q3Canvas

[wysota]

You should map the scrollarea's coordinates to the viewport coordinates either by adding values of the scrollbars or by using mapFromParent.

m_zoomStartPoint = (inverseWorldMatrix()).map(mapFromParent(a_e->pos()));

m_zoomStartPoint = (inverseWorldMatrix()).map(mapFromParent(a_e->pos()));

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[jnana]

Hi ,

Still it is not working.

void
DiagramView :: contentsMouseMoveEvent(QMouseEvent* a_e)
{
    if(cursor().shape() == Qt::CrossCursor) {
        //QPoint myPoint = viewportToContents(a_e->pos());
        m_zoomEndPoint = (inverseWorldMatrix()).map(mapFromParent(a_e->pos()));
        int width = m_zoomEndPoint.x()-m_zoomStartPoint.x();
        int height = m_zoomEndPoint.y()-m_zoomStartPoint.y();
        if((width>0)&&(height>0)) {
            if(!m_zoomRegionRect) {
                //! canvas item do not exist
                m_zoomRegionRect = new Q3CanvasRectangle(m_zoomStartPoint.x(),
                        m_zoomStartPoint.y(),
                        width, height, canvas());
                m_zoomRegionRect->setBrush(Qt::DiagCrossPattern);
                m_zoomRegionRect->setPen(QPen(Qt::darkGreen, 
                    2, Qt::DashDotDotLine));
                m_zoomRegionRect->setZ(100);
                m_zoomRegionRect->show();
            } else {
                m_zoomRegionRect->setSize(width, height);
                canvas()->setChanged(m_zoomRegionRect->boundingRect());
            }
            canvas()->update();
        }
        return;
    }
}
void
DiagramView :: contentsMousePressEvent(QMouseEvent* a_e)
{
    m_zoomStartPoint = (inverseWorldMatrix()).map(mapFromParent(a_e->pos()));
}
 
void
DiagramView :: contentsMouseReleaseEvent(QMouseEvent* )
{
    if(cursor().shape() == Qt::CrossCursor) {
        if(m_zoomRegionRect) {
            m_zoomRegionRect->hide();
            canvas()->update();
            delete m_zoomRegionRect;
            m_zoomRegionRect = 0;
            m_zoomStartFlag = true;    
            emit ZoomToRegion(m_zoomStartPoint, m_zoomEndPoint);
            canvas()->update();
        }
        return;
    }
}

void
DiagramView :: contentsMouseMoveEvent(QMouseEvent* a_e)
{
    if(cursor().shape() == Qt::CrossCursor) {
        //QPoint myPoint = viewportToContents(a_e->pos());
        m_zoomEndPoint = (inverseWorldMatrix()).map(mapFromParent(a_e->pos()));
        int width = m_zoomEndPoint.x()-m_zoomStartPoint.x();
        int height = m_zoomEndPoint.y()-m_zoomStartPoint.y();
        if((width>0)&&(height>0)) {
            if(!m_zoomRegionRect) {
                //! canvas item do not exist
                m_zoomRegionRect = new Q3CanvasRectangle(m_zoomStartPoint.x(),
                        m_zoomStartPoint.y(),
                        width, height, canvas());
                m_zoomRegionRect->setBrush(Qt::DiagCrossPattern);
                m_zoomRegionRect->setPen(QPen(Qt::darkGreen, 
                    2, Qt::DashDotDotLine));
                m_zoomRegionRect->setZ(100);
                m_zoomRegionRect->show();
            } else {
                m_zoomRegionRect->setSize(width, height);
                canvas()->setChanged(m_zoomRegionRect->boundingRect());
            }
            canvas()->update();
        }
        return;
    }
}
void
DiagramView :: contentsMousePressEvent(QMouseEvent* a_e)
{
    m_zoomStartPoint = (inverseWorldMatrix()).map(mapFromParent(a_e->pos()));
}

void
DiagramView :: contentsMouseReleaseEvent(QMouseEvent* )
{
    if(cursor().shape() == Qt::CrossCursor) {
        if(m_zoomRegionRect) {
            m_zoomRegionRect->hide();
            canvas()->update();
            delete m_zoomRegionRect;
            m_zoomRegionRect = 0;
            m_zoomStartFlag = true;    
            emit ZoomToRegion(m_zoomStartPoint, m_zoomEndPoint);
            canvas()->update();
        }
        return;
    }
}

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[Kapil]

hi.

are u deriving the class DiagramView from Q3CanvasView...

For me something like this works pretty fine...

void CanvasMouse::contentsMousePressEvent(QMouseEvent* e)
{
               if(e->button() == Qt::LeftButton)
               {
                    QPoint pPress = inverseWorldMatrix().map(e->pos());
               }
}

void CanvasMouse::contentsMousePressEvent(QMouseEvent* e)
{
               if(e->button() == Qt::LeftButton)
               {
                    QPoint pPress = inverseWorldMatrix().map(e->pos());
               }
}

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though it seems a crude method but try something like this that try to call the mouse events in the class where u have created the canvas... where u have set its size and its view... it might help...

Kapil