Re: Fill column indicator functionality

[Ergus <spacibba@aol.com>]

On Fri, Apr 05, 2019 at 11:10:15AM +0200, Robert Pluim wrote:
>>>>>> On Wed, 03 Apr 2019 14:11:00 +0300, Eli Zaretskii <eliz@gnu.org> said:
>
>    Eli> The changes you made look fine to me.  Let's wait for more
>    Eli> people to try the branch.
>
>Iʼve just tried it.
>
>- etc/NEWS says:
>
>    Customize the buffer-local variables 'display-fill-column-indicator'
>
>but M-x customize-variable doesnʼt know about
>'display-fill-column-indicator'
>
Hi:

Sorry, I forgot to add it to cus-start.el I fixed right now. Ween I set
the variable with set-variable it works for me. (and redisplay is called)

The problem now is that I added it to cus-start.el but when I set it
with the interface, the line does not change at all. Nothing really
happens when I save.

Could anyone tell me what I am missing here please??

>- the manual talks about 'global-display-fill-column-indicator-mode', but
>M-x doesnʼt  know about that function until I
>    (require 'display-fill-column-indicator)
>(this may be due to the way autoloads work in emacs. Thereʼs an entry
>in ldefs-boot.el for it)
>
I have it without the require, so maybe when generating the autoload
(which seems to be an automatic process) it will appear. 

>- the Commentary section in display-fill-column-indicator.el still
>talks about line numbers, and appears truncated.
>
Fixed, thanks!

>- when I turn it on, it chooses \u2502, which is not displayable by my
>default font, but is displayable by a fallback font. I end up with
>empty blocks at the end of each line. I can probably customize
>'fill-column-face' to work around this, but Iʼd expect this to work by
>default (either by using '|' or using the fallback font).
>
I don't really find a right method to fix this because the
char-displayable-p function seems not to be accurate in many
cases. There was a discussion about this before, but there was not a
final agreement I think. And from the char-displayable-p documentation:

```
On a multi-font display, the test is only whether there is an
appropriate font from the selected frame's fontset to display
CHAR's charset in general.  Since fonts may be specified on a
per-character basis, this may not be accurate.
```

Any suggestion here?

>- in org-mode buffers the indicator is displayed as '['. This may be
>related to the previous point (those buffers use yet a third font).
>

>Robert

Ergus