Re: Alt and Command keys in the quartz backend

[Michael Natterer <mitch gimp org>]

On Tue, 2011-09-06 at 11:57 -0700, John Ralls wrote:
> On Sep 6, 2011, at 10:42 AM, Michael Natterer wrote:
> 
> > On Tue, 2011-09-06 at 12:58 -0400, Paul Davis wrote:
> >> On Tue, Sep 6, 2011 at 12:49 PM, Michael Natterer <mitch gimp org> wrote:
> >>> On Tue, 2011-09-06 at 08:27 -0700, John Ralls wrote:
> >> 
> >> [ ... imminent turf war ... ]
> >> 
> >> this seems to be about two different things, neither of which are in
> >> conflict (and i think john actually agrees with this).
> >> 
> >> 1) whether or not the Alt key should generate MOD1 as a modifier
> >> 2) whether or not code that wants to be cross-platform can assume that
> >> they can use MOD1 with its own chosen semantics
> >> 
> >> the problem is that (2) includes GTK, not just applications, and GTK
> >> already makes this assumption. as a result, john changed the modifier
> >> that alt/option generates on OS X, because (2) is not true for OS X.
> >> 
> >> if (2) was fixed so that GTK was not an example of code that assumes
> >> that MOD1 is free for any interpretation on any platform, then (1) is
> >> moot, and it really doesn't matter what the Alt key generates on OS X
> >> (hence, it could be MOD1).
> >> 
> >> but as long as (2) remains an issue within GTK itself, its hard to
> >> argue that a key that has clearly different purposes for a large body
> >> of platform users of OS X should be handled by GTK as if it had some
> >> different meaning based on another platform.
> > 
> > That's not what I'm asking for. The only special meaning of "Alt"
> > in GTK is to invoke mnemonics. Other than that, it's simply a modifier.
> > Same on the Mac, it's just a modifier. Let's just disable the mnemonics
> > on the Mac then.
> > 
> > The fact that the OS uses it to generate special characters is
> > not really relevant here. One X11 window manager "steals" key
> > combo A from the app, the other one key combo B, there is nothing
> > I can do about this.
> > 
> > Turning "Alt" into "Alt" fixes more than it breaks. It fixes e.g.
> > configuring GTK keybindings (you can easily make Alt-cursor do
> > word navigation then, the config file says alt, it's all correctly
> > mapped, the modifier says alt, and it just works).
> > 
> > And it's not just key bindings. Alt-click should be alt-click,
> > there is nothing wrong about that. If the OS decides to use it
> > for its own purposes, then it's the job of higher-level code
> > to be aware of that. 
> > 
> > If we need to change something in GTK as a consequence of that
> > change, then so be it, but please let's not do strange stuff
> > to the quartz' backend's modifier mapping just to accommodate
> > some code in GTK that was never meant to handle the Mac, but
> > can easily be changed to simply do it.
> 
> It's not really different. Getting rid of the hard-coded association between <alt> in an accelerator map or key binding and GDK_MOD1_MASK is part of Paul's (2). I'd map it to GDK_META_MASK, but I'm open to super, hyper, or a new GDK_ALT_MASK (bit 25, perhaps). It *is* the right thing to do, I think, but it's not a quartz-only change and it probably would not be welcome in gtk+-2.24. 

It is not the right thing to do. Why do you insist on that,
and what is wrong about the "hard-coded" association between
ALT and MOD1_MASK? What is the problem about fixing GDK to
map Alt to what is globally considered Alt, and then fix
the platform-specific things in GTK+ afterwards?

--Mitch