Qt mouse movement/action combination - qt

Question

How to manage combined mouse movement (for example left click + midle click + left click release)
I have the method mousePressEvent and mouseReleaseEvent but I did not find the way to combine them.

Answer 1

If you need to combine the information from mousePress and mouseRelease you need to somehow keep track which button is still pressed and which one has already been released again.
Below is a rather simply example which seems to do what you describe (actions indicated by printouts)
Let me know if this helps
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QMouseEvent>
#include <QtCore>
class MyGraphicsView: public QGraphicsView
{
public:
MyGraphicsView( QGraphicsScene *scene, QWidget *parent = 0) : QGraphicsView(scene,parent)
{
active[Qt::LeftButton] = false;
active[Qt::RightButton] = false;
active[Qt::MiddleButton] = false;
}
public slots:
virtual void mousePressEvent( QMouseEvent * event );
virtual void mouseReleaseEvent( QMouseEvent * event );
std::map< Qt::MouseButton, bool > active;
};
void MyGraphicsView::mousePressEvent( QMouseEvent * event )
{
active[event->button()] = true;
if( event->button() == Qt::LeftButton && !active[Qt::MiddleButton] && !active[Qt::RightButton]) {
qDebug() << "select";
} else if (event->button() == Qt::RightButton && !active[Qt::LeftButton] && !active[Qt::MiddleButton] ) {
qDebug() << "property";
} else if ( event->button() == Qt::LeftButton && active[Qt::MiddleButton] && !active[Qt::RightButton]) {
qDebug() << "zoom";
} else if ( event->button() == Qt::MiddleButton && !active[Qt::LeftButton] && !active[Qt::RightButton] ) {
qDebug() << "pan";
}
}
void MyGraphicsView::mouseReleaseEvent( QMouseEvent * event )
{
if( event->button() == Qt::LeftButton && active[Qt::LeftButton] && active[Qt::MiddleButton] ){
qDebug() << "move";
}
active[event->button()] = false;
}
int main( int argc, char **argv )
{
QApplication app(argc, argv);
QGraphicsScene scene;
scene.setSceneRect( -100.0, -100.0, 200.0, 200.0 );
MyGraphicsView view( &scene );
view.show();
return app.exec();
}