Re: Sliders and marks

[Bastien Nocera <hadess hadess net>]

On Wed, 2011-03-02 at 15:22 +0200, Stefan Kost wrote:
> Am 02.03.2011 15:11, schrieb Bastien Nocera:
> > Heya,
> > 
> > Looking at bug https://bugzilla.gnome.org/show_bug.cgi?id=643487 and the
> > original https://bugzilla.gnome.org/show_bug.cgi?id=643486 we figured
> > that it would be best for sliders to point to their marks instead of
> > trying to add labels on the end of scales.
> > 
> > This is Jakub's mockup:
> > http://gitorious.org/gnome-design/gnome-design/blobs/master/mockups/theming/widget-dissect-slider.png
> > And my current implementation:
> > http://img64.imageshack.us/f/keyboardreversedscale.png/
> > 
> > The problem is that GtkScale allows for the marks to be placed above or
> > below scales, and that you can add one mark above, and one below.
> > 
> > I've already added a GTK_STYLE_CLASS_SCALE_HAS_MARKS class to gtk+,
> > should I add a GTK_STYLE_CLASS_SCALE_HAS_MARKS_BELOW and
> > GTK_STYLE_CLASS_SCALE_HAS_MARKS_ABOVE instead, and make the theming
> > engine do something special in the cases where all the marks are on one
> > particular side of the scale?
> > 
> > Do we want to handle vertical scales with marks as well? Are those used
> > at all?
> 
> One use-case I would like to use them for are volume sliders with a db-scale.
> 
> Having left and right or top and bottom marks at the same time sounds like a
> corner case (e.g. a temperature slider with C and F marks).

There would be two separate slider "knobs" available. One with a
direction, and one with a simple dimple (the round one in jimmac's
mockup).

We could either say: "if all the marks are below, we'll draw a pointy
slider, otherwise the round one".

But that would sort of break the clean divide between themess and GTK+
itself (some themes might want to have pointy sliders when things are
above too, etc.).

So we'd need a way to export the marks positions to the engine, and
adding style classes doesn't scale (we'd need to add 4 separate ones for
this to work).