octave-maintainers
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Assistance wanted for Qt ginput() bug #44832


From: Daniel J Sebald
Subject: Re: Assistance wanted for Qt ginput() bug #44832
Date: Fri, 19 Jun 2015 16:20:49 -0500
User-agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.24) Gecko/20111108 Fedora/3.1.16-1.fc14 Thunderbird/3.1.16

On 06/19/2015 03:11 PM, Philip Nienhuis wrote:
As adviced by Rik I'm asking here for some assistance with bug #44832:
ginput() only recognizes key pressed after a first mouse click.
Apparently the Canvas must be made an active object as soon as a figure  is
made active, and not only after it was clicked; but it is unclear how to do
that.

It sounds like pressing the mouse button causes the QGraphicsScene/View to come in focus. You'll have to figure out how to directly make that graphics scene or view the active window so that key events going to the container window are propagated to the canvas. It looks likes the hierarchy goes back to QWidget:

GLCanvas::keyPressEvent (QKeyEvent* xevent)
class GLCanvas : public QGLWidget, public Canvas
class Q_OPENGL_EXPORT QGLWidget : public QWidget

So you may be able to make the canvas the active window with:

http://doc.qt.io/qt-4.8/qwidget.html#activateWindow

if somewhere in construction there is pointer access to it.  E.g.,

  canvaspointer->activateWindow ();

The only concern would be that something else within the container window is initially the active window (some button, some toolbar, etc.) and whether there is some way through user action that could be made active again such that the canvas loses focus again somehow. Another approach would be to rewrite the keyPressEvent of the container class so that it always redirects the event to the canvas. In theory straightforward, just perhaps a little confusing to follow given GLCanvas is derived from two classes.

Some related info:

http://doc.qt.io/qt-4.8/qgraphicsscene.html#focusInEvent
http://doc.qt.io/qt-4.8/qgraphicsscene.html#focusInEvent
http://doc.qt.io/qt-4.8/qgraphicsview.html#focusInEvent
http://doc.qt.io/qt-4.8/qwidget.html#keyPressEvent

Dan


Thanks,

Philip



--
View this message in context: 
http://octave.1599824.n4.nabble.com/Assistance-wanted-for-Qt-ginput-bug-44832-tp4671063.html
Sent from the Octave - Maintainers mailing list archive at Nabble.com.



--

Dan Sebald
email: daniel(DOT)sebald(AT)ieee(DOT)org
URL: http://www(DOT)dansebald(DOT)com



reply via email to

[Prev in Thread] Current Thread [Next in Thread]