Re: Configuring fontsets with `unicode-fonts` [Was: Re: Should minibuffer prompt be made intangible by default?]

[Eli Zaretskii <eliz@gnu.org>]

> From: Alexis <flexibeast@gmail.com>
> Cc: emacs-devel@gnu.org
> Date: Sat, 02 Apr 2016 19:57:45 +1100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Installing fonts doesn't necessarily resolve the fontset 
> > configuration problems, especially since no package can know 
> > what other fonts are available on the end-user system.
> 
> Sorry, i'm not sure you understand what the `unicode-fonts` 
> package does?

I've read the code, but that doesn't necessarily mean I didn't miss
anything, of course.

However, I did read README.md as well, and upon re-reading now the
text you posted, I find nothing in it that would contradict what I
said.

> It doesn't provide fonts itself, but configures fontsets to use
> fonts on a users' system for maximum Unicode coverage.

I know; I've read the code before that original reply.

Maybe we are talking about 2 different issues.  My understanding of
the original stackexchange question was that the problems there were
related to the fact that fontset setup caused some characters to be
displayed with fonts other than what the user saw before changing his
setup.  It should be clear that the fonts used before changing the
setup depend on what is installed on the user's system, something that
no package can take into consideration.  Thus this part of what I
wrote:

> > Installing fonts doesn't necessarily resolve the fontset 
> > configuration problems, especially since no package can know
> >                         ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
> > what other fonts are available on the end-user system.
> > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

IOW, the problem here that I referred to is this:

  . User complains that some characters cannot be displayed
  . User is advised to install a fontset setup and additional fonts to
    fix that
  . The fontset setup causes some characters previously displayed with
    font A to be now displayed with font B, and the user doesn't like that

My point is that, once you get to the 3rd item, no external package
can be the correct answer; instead, you need to teach the user to
configure his/her fontset according to his/her preferences.  In
particular, the fontset setup should be based not only on Unicode
blocks, but also on the capabilities of the fonts present in the
original system configuration, and the user's preferences for using
particular font(s) for displaying particular ranges of characters.