Re: highlight-indent-guides in display engine

[Ergus <spacibba@aol.com>]

On Fri, Jul 12, 2019 at 09:57:24AM +0300, Eli Zaretskii wrote:
>> Date: Fri, 12 Jul 2019 02:21:27 +0200
>> From: Ergus <spacibba@aol.com>
>> Cc: emacs-devel@gnu.org
>>
>> >I don't think I understand: what do you mean by "add the indicator"?
>> >How would this indicator look like?
>> >
>> Maybe a vertical bar (like our previous column indicator) or a width
>> line. Or something customizable somehow. We just need to look around,
>> there are several alternatives. We must chose the one that fits better
>> and produces less complications for us. But provides the functionality
>> somehow.
>>
>> I don't thing how the indicator looks like may be a problem, but how
>> accurate or specific it behaves.
>>
>> I am just looking around and Geany adds some vertical points as the
>> indicator positions (every tab or every x spaces). But the spaces are
>> only "indicated" when used for the indentation..
>>
>> Sublime behaves in the same way. But there is an option to highlight the
>> indicator only in the blocks around the current cursor. (As in the
>> attachement)
>
>I didn't receive any attachments with your message.
>
>> Athom on the other hand seems to behave as in the
>> highlight-indent-guides.el package:
>> https://atom.io/packages/indent-guide-improved
>>
>> With the animations and so on. Which seems to be the most complete
>> behavior, but less efficient.
>
>The animations and highlighting inside the current block should be in
>Lisp, not in the display code.  If at all.
>
>> In all the cases I just see that they add the indicator based on the
>> characters between the beginning of the line and the indentation (first
>> non blank character) not looking at the previous lines. They ignore if
>> there is a previous line  with wrong indentation or if the current line
>> adds 3 tabs more respecting to the previous one.
>>
>> So, implementing it in this way doesn't seems to be so complex right?
>
>So basically you are talking about displaying some special glyph at
>every tab stop inside leading whitespace of a line, or making each
>tab-stop width have a different background color?  Yes, this should be
>possible to do in the display code.  I just hope enough people will
>see this as sufficient, because if most current users of these
>packages won't switch, this new feature will not be worth its
>development, documentation, and maintenance effort.  Maybe we should
>ask on Reddit first?

Hi Eli:

I think several people will prefer to have the whole functionalities and
options to customize (as usual in emacs if there is a feature that
solves N issues, then somebody will come asking for the N+1 option.)

But in any case the minimal solution will be enough for a big number of
users if it compensates with performance.

But I agree that we must ask in reddit. May you please add a reddit
poster about?  Because as I don't use reddit very often, most users
ignore them.

Thanks in advance,
Ergus