[Interest] Pan text in QPlainTextEdit with one finger?

Igor Mironchik igor.mironchik at gmail.com
Wed Dec 18 09:22:15 CET 2013


In QPlainTextEdit::event( QEvent * e )

I've found the next code:


     else  if  (e->type()  ==  QEvent::Gesture)  {

         QGestureEvent  *ge  =  static_cast<QGestureEvent  *>(e);

         QPanGesture  *g  =  static_cast<QPanGesture  *>(ge->gesture(Qt::PanGesture));

         if  (g)  {

             QScrollBar  *hBar  =  horizontalScrollBar();

             QScrollBar  *vBar  =  verticalScrollBar();

             if  (g->state()  ==  Qt::GestureStarted)

                 d->originalOffsetY  =  vBar->value();

             QPointF  offset  =  g->offset();

             if  (!offset.isNull())  {

                 if  (QApplication::isRightToLeft())

                     offset.rx()  *=  -1;

                 //  QPlainTextEdit  scrolls  by  lines  only  in  vertical  direction

                 QFontMetrics  fm(document()->defaultFont());

                 int  lineHeight  =  fm.height();

                 int  newX  =  hBar->value()  -  g->delta().x();

                 int  newY  =  d->originalOffsetY  -  offset.y()/lineHeight;





         return  true;


#endif  //  QT_NO_GESTURES

It told to me that QPlainTextEdit should support "pan gesture" and text should be paned with
fingers. But in my test app when I move finger in QPlainTextEdit I receive selection of the text.
And I saw that in event( QEvent * e ) method appear QEvent::InputMethodQuery event instead of

But with two fingers I receive sometimes QEvent::Gesture and text scrolled but in wrong direction.
It's ugly to not to have scrolling with one finger. May be we should post suggestion to the

Any ideas?!

> Hi,
> sorry for 3rd posting about same issue. I didn't know the right
> mailing list.
> I have tried it several hours and get only a pan gesture with two 
> fingers,
> with text selection (what I not want).
> I have used QPlainTextEdit, QTextEdit - with Qt Designer or subclass 
> (grabGesture(Qt::PanGesture)) -
> in a simple 'MainWindow' (c++).
> (I have tried the gesture source code from the QPLainTextEdit 'event' 
> function.)
> I got never the result like with the 'aboutQt' (QMessageBox) call.
> I have Installed:
> Qt 5.2.0 for Android (Windows 32-bit, 761 MB),
> Asus MeMO Pad HD 7 (Android 4.2.2),
> Samsung Galaxy S4 mini (Android 4.2.2)
> I want to show results in a QPlainTextEdit or QTextEdit without text 
> selection, but pan
> up and down (and it would be nice, left and right).
> Can somebody help me, please?
> Thanks,
>     Thomas
> _______________________________________________
> Interest mailing list
> Interest at qt-project.org
> http://lists.qt-project.org/mailman/listinfo/interest

Best Regards,
Igor Mironchik.

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