QNativeGestureEvent Mac OSX TrackPad finger Capture Operation zoom Solved. :-)

patrik08

At top from my QWidget QAbstractScrollArea i put grabGesture ...

this->grabGesture(Qt::SwipeGesture,Qt::DontStartGestureOnChildren);
this->grabMouse();
this->setContentsMargins(0,0,0,0);
this->setAcceptDrops(true);

after from main event( QEvent * e) i ast all QNativeGestureEvent
#include <QInputEvent>
#include <QNativeGestureEvent>

& QNativeGestureEvent give value() of the swiped distance and more info about pos on screen
From the inomming event that i see .. its possibel to rotate paint QWidget...

///  mac  trackpad https://support.apple.com/en-us/HT204895
bool DrawDoument::gestureNative( QNativeGestureEvent * e ) {
   QTextStream  xcout(stdout, QIODevice::WriteOnly);
   QString dir;
     if ( e->value() < 0) {
         distanceswip = distanceswip - e->value();
         setZoom( scaleFaktor - TRACKPADSTEEPS );  /// SCALING_STEEP = 0.075555555
        dir = "zoom in";
      } else {
         distanceswip = distanceswip + e->value();
         setZoom( scaleFaktor + TRACKPADSTEEPS );
         dir = "zoom out";
       }
  xcout << "-----------------swip (" << e->value()  << ")" <<  dir << "x" << POINT_TO_MM(distanceswip) <<"\r";
  e->accept();
  return true;
}
bool DrawDoument::event( QEvent * e) {
  if ( e->type() == QEvent::NativeGesture ) {
     return gestureNative(static_cast<QNativeGestureEvent*>(e));
  }
  strak = strak + 0.11; /// visual sleep?
  const int xmac = e->type();
  QTextStream  xcout(stdout, QIODevice::WriteOnly);
  xcout << "E," <<strak << ":->" <<  __FUNCTION__ << " - " << xmac <<"\r";
  return QAbstractScrollArea::event(e);
}

SGaist

Thanks for sharing your findings !