Re: About the :distant-foreground face attribute

[Joel Mccracken]

It seems like "contrast" could be used to explain the difference in a more 
intuitive way. 

On Jan 7, 2014, at 12:28 PM, Drew Adams <address@hidden> wrote:

>>> What is the purpose of this face attribute, newly introduced for
>>> 24.4?
>> 
>> Too lazy to read documentation?
>> 
>> "`:distant-foreground'
>>     Alternative foreground color, a string.  This is like
>>     `:foreground'
>>     but the color is only used as a foreground when the background
>>     color is near to the foreground that would have been used.
>>     This is useful for example when marking text (i.e. the region
>>     face).
>>     If the text has a foreground that is visible with the region
>>     face, that foreground is used.  If the foreground is near the
>>     region face background, `:distant-foreground' is used instead
>>     so the text is readable."
> 
> I see.  And just how does a user override this automatic "cleverness"?
> How can a user really make her preference for the face take effect?
> 
> This kind of DWIMity should always allow users to take control back,
> and preferably easily.  What you think might be best for all users
> all the time might not be what some user thinks is best for herself.
> 
> And what about all of the existing code that tests :foreground or
> otherwise expects it to reflect the actual foreground used?  Is that
> code broken now, because Emacs substitutes a :distant-foreground
> color behind its back?  Must all such code now change to test first
> one and then the other?
> 
> When was this design OK'd (and why)?
> 
>>> First of all, the name :distant-foreground is not intuitive.  What
>>> does "distant" mean in this context?
>> 
>> The same as in any other context, far removed from something else,
>> i.e. the background.
> 
> I agree with Yidong about the name.  This is apparently a fallback,
> alternative color, when (you) think the color specified by the
> user or program is inappropriate.
> 
>>> Besides that, the implementation seems rather incomplete.  The
>>> Customize interface, `modify-face', `face-spec-reset-face', and
>>> other parts of Emacs haven't been updated for the existence of
>>> this face attribute.
>> 
>> That is on purpose.  It is supposed to be automatically calculated.
> 
> So what?  All the more reason to bring it out into the open, so
> users can know about it (and try to find some way to work around it,
> if they like).
> 
>>> It's unclear what functions like `face-foreground' should now do
>>> if there's a :distant-foreground.
>> 
>> No it is not.
> 
> Yes it is.  See above.  Search the distributed code and the Internet
> for uses of "foreground" in Emacs Lisp code.  How much of that code
> now needs to be modified to accommodate this gratuitous change.
> 
> Was there a real problem, reported by a real user, that this change
> attempts to fix?  Or is this just someone's clever brainchild for
> making Emacs smarter?
> 
>>> This all sounds like an invitation for more bugs.  In my opinion,
>>> this feature is a bad idea.
> 
> +1
> 
>> All new features invite new bugs, so are you saying we should never
>> add new features?
> 
> All new features should be proposed and discussed, before being cast
> into the product.  That's my humble opinion.
> 
>> Your opinion is not very interesting, but if you have core for an
>> alternative approach that would be interesting.
> 
> Why is any approach needed?  What is the (real) problem that needs
> solving?
>