[vtkusers] paint on QVTKWidget

[Girish Lande]

Hi All,

I am trying to show painting effect on QVTKwidget using QT painting
mechanism.
As User press mouse button and move cursor I want to paint circular region
under cursor. For this I have derived my widget class from QVTKwidget  and
am overriding its paintevent method.

If I do same operation while overriding my class from QWidget it works fine,
But wth QVTKWidget I am not having any luck. It doesn't show painting
effect.

Following is my source code . Could you please help me figure out problem
in my source code ?

header file
-----------------------

#ifndef MYWIDGET_H

#define MYWIDGET_H


#include <QWidget>

#include <QVTKWidget.h>


class MyWidget : public QVTKWidget

{

    Q_OBJECT

public:

    explicit MyWidget(QWidget *parent = 0);


protected:

   // QPaintEngine * paintEngine() const;

    void paintEvent(QPaintEvent *event);

    void mousePressEvent(QMouseEvent *event);

    void mouseReleaseEvent(QMouseEvent *event);

    void mouseMoveEvent(QMouseEvent* event);

    int x;

    int y;

std::vector<int> vec;

bool m_pressed;


signals:


public slots:

};


#endif // MYWIDGET_H


Source file
------------------------

#include "mywidget.h"

#include <QPainter>

#include <QPen>

#include <QPolygon>

#include <QMouseEvent>

#include <QLabel>

#include <qdebug.h>


MyWidget::MyWidget(QWidget *parent) : QVTKWidget(parent)

{

x=100;

y=100;

m_pressed = false;

}


//QPaintEngine * MyWidget::paintEngine() const

//{

//  return QVTKWidget::paintEngine();

//}


void MyWidget::paintEvent(QPaintEvent *event)

{

    //create a QPainter and pass a pointer to the device.

    //A paint device can be a QWidget, a QPixmap or a QImage

    QPainter painter(this);


    //create a black pen that has solid line

    //and the width is 2.

    painter.setBrush(QBrush(Qt::red));

    painter.setPen(QPen(Qt::red));

    int radius = 20;

    bool point_Flag = false;

    if (!point_Flag) {

        qDebug() << "vector size:" <<vec.size();

        int xx,yy;

        for(int i=0;i<vec.size();i+=2) {

            //draw a point

            xx = vec[i];

            yy=vec[i+1];

            painter.drawEllipse(QPointF(xx,yy), radius, radius);

        }

    } else {

        int mx,my;

        for(int i=0;i<vec.size();i+=2) {

            //draw a point

            mx = vec[i];

            my = vec[i+1];

            int x1 = mx - radius;

            int x2 = mx + radius;

            int y1 = my - radius;

            int y2 = my + radius;


            double inc = 1;

            for (int _x = x1, deltax = -radius; _x <= x2; _x+=inc, deltax+=inc)

            {

                for (int _y = y1, deltay = -radius; _y <= y2; _y+=inc,
deltay+=inc)

                {

                    float dist = sqrtf(deltax*deltax + deltay*deltay);

                    if (dist<radius) {

                        painter.drawPoint(_x,_y);

                    }

                }

            }

        }

    }

    QVTKWidget::paintEvent(event);

}


void MyWidget::mousePressEvent(QMouseEvent *event)

{

    x=event->x();

    y=event->y();

    m_pressed = true;

    QVTKWidget::mousePressEvent(event);

}


void MyWidget::mouseReleaseEvent(QMouseEvent *event)

{

    x=event->x();

    y=event->y();

    vec.clear();

    update();

    m_pressed = false;

    QVTKWidget::mouseReleaseEvent(event);

}


void MyWidget::mouseMoveEvent(QMouseEvent *event)

{

    if (m_pressed) {

        x=event->x();

        y=event->y();

        vec.push_back(x);

        vec.push_back(y);

        update();

    }

    QVTKWidget::mouseMoveEvent(event);

}



-- 
thanks & regards,
Girish

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