[LyX/master] Make all unbreakable spaces of the same Color_latex color

[Daniel]

On 2020-06-24 08:15, Daniel wrote:
> On 2020-06-23 23:46, Jean-Marc Lasgouttes wrote:
>> Le 23/06/2020 à 23:11, Jean-Marc Lasgouttes a écrit :
>>> commit 49e1466f93b63b0489549d40ebbde944eff1c7f6
>>> Author: Jean-Marc Lasgouttes <lasgouttes at lyx.org>
>>> Date:   Tue Jun 23 23:33:37 2020 +0200
>>>
>>>      Make all unbreakable spaces of the same Color_latex color
>>>      Of course, this means that negative spaces cannot be recognized 
>>> anymore.
>>
>> I did not mean to commit this yet, but it is a good occasion to 
>> discuss the issue of space color. I can revert that if needed.
>>
>> I am not sure what was the logic of colors right now.
> 
> A wild guess on the logic:
> 
> There are two visual dimensions at which spaces are distinguished: color 
> (red/blue) and height (high/low)
> 
> high/blue: positive (normal) spaces
> high/red: negative spaces
> 
> It makes sense to me that these spaces fall into one category (high) and 
> that positive/negative is distinguished as blue/red.
> 
> Then there are two more spaces left:
> 
> low/red: protected
> low/blue: interword
> 
> To distinguish them from the other spaces they are low. To distinguish 
> them from each other (and don't introduce new colors) they are red/blue.

I don't find the last red/blue distinction for special spaces nice 
because it is used for negative space too and the high/low distinction 
is hard to see. Instead for these special spaces, there could be a a 
(blue) tilde (˜), as used in LaTeX, on the middle or bottom of the line 
for a protected space instead of the "space-box". I am not sure what 
would be a good symbol for the interword space though: maybe also the 
latex symbol (\) or a (blue) bullet (• or ◦), as used commonly to mark a 
normal space, on the middle or bottom. Though I am not sure whether 
those symbols interfere with some other symbols (like linguistic ones or 
so). Others might know.

Speaking of colors:

- I find that New Page and Page Break could get the same color since 
there is text added that distinguishes the two.

- And the end of line and line break symbols are easy to distinguish 
too, so they could get the same color.

So, why not give those last four all the same color?

Daniel