Re: NS port and fancy OS X scrollbars

[Alan Third]

On Wed, Feb 24, 2016 at 10:56:36AM +0100, Anders Lindgren wrote:
> It's hard to know. One way to handle this is to keep both implementations
> around. Clearly, the combination of having scroll bars to the left and make
> them floating won't be supported. This might be needed anyway since I'm not
> sure if GNUStep supports floating scroll bars.

The good side of this is that if we did implement an NSScrollView to
handle the scroll bars then GNUStep and older versions of OS X that
don't support the floating versions will fall-back to the "legacy"
scroll bars. At least, that's how the documentation reads to me.

It would also mean that whether the scroll bars were floating or
legacy would depend on the system setting in system preferences ->
general. Although we could force them back to legacy at runtime if
required.

Here's a wee bit of information on when you do and dont' get floating
scrollbars:

https://developer.apple.com/library/mac/releasenotes/MacOSX/WhatsNewInOSX/Articles/MacOSX10_7.html#//apple_ref/doc/uid/TP40010355-SW3

(search for "overlay scrollbars")

> Am I right about this? If so then it seems the only way to get the
> > floating scrollbars would be to recreate the effect ourselves, which I
> > suspect is rather a lot of work.
> >
> 
> If you are correct, then I would suggest that we shouldn't pursue this. If
> it's not possible to implement this in a clean OS friendly manner, we risk
> ending up with complex, fragile, code that might not work on future OS X
> versions.

I think we need to find someone who knows a bit more about exactly how
Emacs draws windows or I need to just keep looking until I figure out
how it works.

Thanks!
-- 
Alan Third