[Qt-interest] How Can I Paint on QGraphicsView

[Sujan Dasmahapatra]

Dear Prasanth
Can we add a QGraphicsPathItem intot the scene by addItem()
m_scene.addItem(m_pathItem)

I implemented this but I am not able to see the rectangle.!! whatd could be
the reason any  idea.

On Mon, Aug 17, 2009 at 5:46 PM, Prashanth Udupa
<prashanthudupa at yahoo.com>wrote:

>   You can reimplement mouse event handlers in QGraphicsView to create a
> QGraphicsPathItem. See code below.
>
>  #include <QtGui>
>
> class GraphicsView : public QGraphicsView
> {
> public:
>     GraphicsView() : m_scene(this), m_pathItem(0) {
>         m_scene.setSceneRect(-2000, -2000, 4000, 4000);
>         setScene(&m_scene);
>
>         setSceneRect(-2000, -2000, 4000, 4000);
>     }
>
>     ~GraphicsView() { }
>
> protected:
>     void mousePressEvent(QMouseEvent* me) {
>         QGraphicsView::mousePressEvent(me);
>
>         if(!me->isAccepted() && !m_pathItem)
>         {
>             m_pathItem = new QGraphicsPathItem;
>             m_scene.addItem(m_pathItem);
>
>             QPainterPath path;
>             path.moveTo(mapToScene(me->pos()));
>             m_pathItem->setPath(path);
>             m_pathItem->setPen(QPen(Qt::blue, 3));
>         }
>     }
>
>     void mouseMoveEvent(QMouseEvent* me) {
>         if(m_pathItem)
>         {
>             QPainterPath path = m_pathItem->path();
>             path.lineTo(mapToScene(me->pos()));
>             m_pathItem->setPath(path);
>         }
>         else
>             QGraphicsView::mouseMoveEvent(me);
>     }
>
>     void mouseReleaseEvent(QMouseEvent* me) {
>         m_pathItem = 0;
>         QGraphicsView::mouseReleaseEvent(me);
>     }
>
> private:
>     QGraphicsScene m_scene;
>     QGraphicsPathItem* m_pathItem;
> };
>
> int main(int argc, char** argv)
> {
>     QApplication a(argc, argv);
>
>     GraphicsView gView;
>     gView.show();
>
>     return a.exec();
> }
>
>
> HTH.
>
> / Prashanth
>
>  ------------------------------
> *From:* Sujan Dasmahapatra <sujan.dasmahapatra at gmail.com>
> *To:* qt-interest at trolltech.com
> *Sent:* Monday, August 17, 2009 2:27:33 PM
> *Subject:* [Qt-interest] How Can I Paint on QGraphicsView
>
> Dear Friends
> How can I draw on the QGraphicsView using a QPainter, I want to draw
> continuously on the view when user Press mouse till Release mouse.
> I tried to implement paintEvent() method but that can be used for widget
> painting and not QGraphicsView.
> Any other means are there to paint on the QGraphicsView ?? Please help me
>
> --
> Thanks & Regards
> S. Dasmahapatra
> B.E. (Aeronautics-Aerodynamics)
> Bangalore, India
> Ph:91-9900839788
> Office:91-80-66470248
> mail id : sujan.dasmahapatra at gmail.com
>
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>



-- 
Thanks & Regards
S. Dasmahapatra
B.E. (Aeronautics-Aerodynamics)
Bangalore, India
Ph:91-9900839788
Office:91-80-66470248
mail id : sujan.dasmahapatra at gmail.com
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