[Solved] Is it possible? I want to paint on QGraphicsScene !!HELP..

NandiniN

to my paint application need to insert mousepress,release and move events to draw on graphics scene..and other functionalists i want it same as "Diagram Scene"..how can i approch to this.

p3c0

Hi,

The best option would be to subclass QGraphicsScene and reimplementing its mousePressEvent, mouseMoveEvent and mouseReleaseEvent.
For Drawing you can use "QGraphicsPathItem":http://qt-project.org/doc/qt-4.8/qgraphicspathitem.html and then "setPath":http://qt-project.org/doc/qt-4.8/qgraphicspathitem.html#setPath to "QPainterPath":http://qt-project.org/doc/qt-4.8/qpainterpath.html

Here'a an example..
@
#include "paintscene.h"

PaintScene::PaintScene(QObject *parent) :
QGraphicsScene(parent)
{
pressed = false;
}

void PaintScene::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
m_item = new QGraphicsPathItem();
QPainterPath path;
path.moveTo(event->scenePos());
m_item->setPath(path);
addItem(m_item);
pressed = true;
}

void PaintScene::mouseMoveEvent(QGraphicsSceneMouseEvent *event)
{
if(pressed)
{
QPainterPath path = m_item->path();
path.lineTo(event->scenePos());
m_item->setPath(path);
}
}

void PaintScene::mouseReleaseEvent(QGraphicsSceneMouseEvent *event)
{
pressed = false;
m_item = NULL;
}
@
--- paintscene.h

@
#ifndef PAINTSCENE_H
#define PAINTSCENE_H

#include <QGraphicsScene>
#include <QGraphicsPathItem>
#include <QGraphicsSceneMouseEvent>

class PaintScene : public QGraphicsScene
{
Q_OBJECT
public:
explicit PaintScene(QObject *parent = 0);

protected:
void mousePressEvent(QGraphicsSceneMouseEvent *event);
void mouseMoveEvent(QGraphicsSceneMouseEvent *event);
void mouseReleaseEvent(QGraphicsSceneMouseEvent *event);

signals:

public slots:

private:
QGraphicsPathItem *m_item;
QPointF previous;
bool pressed;

};

#endif // PAINTSCENE_H
@

Hope this helps a bit..

NandiniN

hey thanku :)