[Digikam-devel] KDE4 KDoubleNumInput -> QDoubleSpinBox ???

[Laurent Montel]

On Wednesday 23 April 2008 08:58:08 Gilles Caulier wrote:
> 2008/4/23 Laurent Montel <montel at kde.org>:
> > On Tuesday 22 April 2008 18:11:19 Laurent Montel wrote:
> >  > On Tuesday 22 April 2008 17:53:28 Gilles Caulier wrote:
> >  > > 2008/4/22 Marcel Wiesweg <marcel.wiesweg at gmx.de>:
> >  > > >  > Perhaps it's the problem in my KDE4 port ?
> >  > > >
> >  > > >  Looks like a KDE bug:
> >  > > >
> >  > > >  Look at the code from knuminput.cpp (current trunk):
> >  > > >         // upcast to base type to get the minimum/maximum in int
> >  > > > form: QDoubleSpinBox * spin = d->spin;
> >  > > >         int slmax = spin->maximum(); <-- What if maximum is 0.4?
> >  > > > Slider's maximum is 0. int slmin = spin->minimum(); <-- same for
> >  > > > this int slvalue = spin->value(); <--
> >  > > >         int slstep = spin->singleStep(); <-- Step 0.01? slstep is
> >  > > > 0 ...
> >  > > >             priv->m_slider = new QSlider(Qt::Horizontal, this);
> >  > > >             priv->m_slider->setMinimum(slmin);
> >  > > >             priv->m_slider->setMaximum(slmax);
> >  > > >             priv->m_slider->setSingleStep(slstep);
> >  > > >             priv->m_slider->setValue(slvalue);
> >  > > >
> >  > > >  Look at compilation warning:
> >  > > >
> >  > > > /home/marcel/freshmeat/multimedia/kde4/src/KDE/kdelibs/kdeui/widge
> >  > > >ts/kn um input.cpp:834: warning: converting to 'int' from 'double'
> >  > > >
> >  > > >
> >  > > >
> >  > > >  Looking at the docs: QDoubleSpinBox::singleStep() is a double
> >  > > > value, here converted to an int. Converting 0.01 to int results in
> >  > > > 0. QSlider only takes integer arguments, so the ints need to be
> >  > > > mapped to double. The code above is not suitable for ranges and
> >  > > > steps in [0; 1], has very bad results for [1; 10], and may begin
> >  > > > to work in the hundreds.
> >  > >
> >  > > You has right Marcel.
> >  > >
> >  > > I fork your message to Laurent Montel to fix the problem in KDELibs.
> >  > >
> >  > > Best
> >  > >
> >  > > Gilles Caulier
> >  >
> >  > Waou... it's a big bug.
> >  > I will look at it this night (not time now)
> >  > I add it to my todo
> >
> >  Marcel is right it can't work.
> >  For the moment we have just a QSlider which works with integer.
> >  It will necessary to create a "QDoubleSlider" if we want to make it
> > work. I will look at if it's possible.
> >
> >  Regards
>
> Laurent.
>
> There is something that i don't understand : KDoubleNumInput already
> exist in KDE3 and work very well. When this widget have been ported to
> KDE4, no regression regression tests have been done ?

In kde3 there was a KDoubleSpinBox but it was removed for kde4 (I don't know 
why). So it's necessary to readd/port it (if possible)

> Gilles



-- 
Laurent Montel,
KDE/KOffice developer, Qt consultancy projects
Klarälvdalens Datakonsult AB, Platform-independent software solutions