[Qt-interest] QPlainTextEdit has broken layout after hide(), show()

[Nikos Chantziaras]

On 06/21/2011 10:24 PM, Kevin Funk wrote:
> Tuesday 21 June 2011, Nikos Chantziaras<realnc at arcor.de>:
>> I came across a strange glitch with QPlainTextEdit: When I modify it
>> with insertPlainText() while the QPTE is hidden and then show() it, the
>> contents are all messed up and will only show correctly is the user
>> resizes the widget.  Calling update() after show() does not help.
>> Calling document()->setModified() and/or document()->markContentsDirty()
>> doesn't help either.
>>
>> Any solutions to this?  And should this be considered a bug that should
>> be reported?
>
> I think I had to solve the same issue just recently:
>
> You could try this code to force a re-layout of the QTPE contents:
> QEvent e(QEvent::FontChange);
> QApplication::sendEvent(textEdit,&e);
>
> This is from [1].
>
> I personally think this should be considered a bug in
> QTextDocument/QAbstractTextDocumentLayout.
>
> [1] http://lists.trolltech.com/qt4-preview-feedback/2005-02/thread01030-0.html

Doesn't work, unfortunately.  The only way I found that works is quite 
ugly (and probably slow):

   log->show();
   log->setPlainText(log->toPlainText());
   log->verticalScrollBar()->triggerAction(QScrollBar::SliderToMaximum);

I'm not sure if this has anything to do with the way I insert text into 
it though:

   log->moveCursor(QTextCursor::End);
   log->insertPlainText(logMsg);
   log->verticalScrollBar()->triggerAction(QScrollBar::SliderToMaximum);

I certainly can't see anything wrong with it.