[tuhopuu-devel] Re: [tuhopuu-cvs] CVS commit: tuhopuu3/source/blender/src buttons_object.c buttons_scene.c buttons_shading.c interface.c space.c

[Martin Poirier]

--- Matt Ebb <matt at mke3.net> wrote:
> 
> On 5 Apr 2005, at 11:52 AM, Matt Ebb wrote:
> 
> >  * Allow ROW buts to toggle bits as well as TOGs.
> Syntax is pretty
> >   similar, use ROW|BIT|# where # is the bit
> position, 1.0 for the
> >   'min' and 0.0 and 1.0 for the 'max' values. More
> explanation to
> >   come on tuhopuu-dev
> 
> When I first asked Ton about this, he didn't really
> understand why it 
> was necessary, and I can imagine some of you more
> programming minded 
> folks may be wondering the same. i.e. "a bit is a
> bit, and switching it 
> on and off with a TOG button is all you need,
> right?" Well, no. What's 
> important to the user is not that it's a bit, but
> what that bit 
> represents. And it so happens that bits are a
> convenient and memory 
> saving way to store not only a choice between on and
> off, but also a 
> choice between two discrete options.
> 
> Conceptually, this is the difference between
> "something and nothing" 
> and "something and something else". Toggle buttons
> work great when you 
> want to represent something vs nothing, but not for
> the latter case. An 
> example of this is the [OB] and [ME] buttons in
> material buttons, to 
> choose whether a material is linked to the Object
> block or the Mesh 
> block. This is a choice between two separate states,
> but internally, 
> this is just toggling a bit: MAT_ON_OB. Representing
> it like with a 
> toggle button in the interface would be very
> ambiguous. What would it 
> mean to turn off the 'Material on Object' button?
> Would it not link the 
> material at all? Would it link it to the Scene or
> the World? So 
> instead, there are the two [OB] and [ME] buttons to
> represent the two 
> different states that you can choose between.
> 
> Historically, this has been done with a bit of a
> hack, putting a TOG 
> and a TOGN button next to each other, and hoping
> that nobody would 
> realise that they're not actually row buttons since
> although they 
> looked like rows, they still functioned as toggles
> (i.e. click a button 
> twice and the counterpart is selected). With the new
> button design in 
> t3, ROWs look different to TOGs, and made those
> TOG/TOGN pairs look 
> very weird and ugly. So this last commit is just
> giving a proper 
> solution to that past hack.
> 
> Anyway, a bit of a digression, I just thought this
> info might be 
> interesting or useful to someone.

It's always useful to see the thoughts process going
on before decisions on changes, wish we could see more
of that (which is as much a note to myself as to
others, mind you ;) )

regards,
Martin

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