Re: [PATCH] Re: About the :distant-foreground face attribute

[Daniel Colascione <dancol@dancol.org>]

On 01/14/2014 12:01 PM, Jan Djärv wrote:
> 14 jan 2014 kl. 19:47 skrev Daniel Colascione <dancol@dancol.org>:
>
>> On 01/14/2014 03:44 AM, Jan D. wrote:
>>> Daniel Colascione skrev 2014-01-14 11:44:
>>>> On 01/14/2014 01:34 AM, Jan D. wrote:
>>>>>>> Given the use case at hand, we know for a fact that the background is
>>>>>>> the region background, so I don't understand why a calculated
>>>>>>> foreground
>>>>>>> is needed.  Just pick one that matches the background.
>>>>>>> There might be other use cases where a calculated foreground makes
>>>>>>> sense, but my imagination fails me here.
>>>>>>
>>>>>> Calculated foreground colors look better: they resemble the font-lock
>>>>>> colors on which they're based.
>>>>>
>>>>> For the region case, that would imply the possibility of different
>>>>> foregrounds for marked text, none which is the actual font-lock color.
>>>>
>>>> It *is* the same color in the sense that the code we generate has the
>>>> same hue. How on earth is that worse than changing arbitrary font-locked
>>>> pieces of text to the system selection foreground color?
>>>
>>> Because the system color foreground is (presumably) choosen to look good
>>> together with the system color background.
>>
>> Yes, and a color we algorithmically generate from a font-lock face will *also* look good against that background color, but 1) will be distinct from other faces replaced for lack of contrast, and 2) will be visually similar to the pre-highlight face. Have you tried the patch?
>
> No.  If Emacs generates a color, Emacs desides what looks good.  If
> the system defines a color, the system (or the user if customized)
> desides what looks good.  I don't think it matters what I think about
> colors generated by your patch, I might even think they look better
> than many system defined colors.  But as a principle I think the
> desision is not Emacs to make *by default*.  Users may of course
> apply customizations to Emacs and change it.

In 24.4, Emacs has already been changed to override the system selection 
foreground color with various font-lock faces. Why is it okay to do that 
when there's no contrast problem, but suddenly, when there's a contrast 
problem, we can say that the principle of following system colors is 
important? You're applying this principle very selectively. If you're 
going to override the system color selection, you need to do it well and 
consistently, and automatic contrast adjustment is the best way to go 
about solving the inevitable contrast problems that arise when you 
combine colors you control with colors you don't.