Re: highlight-indent-guides in display engine

[Ergus <spacibba@aol.com>]

On Thu, Jul 11, 2019 at 10:15:21PM +0300, Eli Zaretskii wrote:
>> Date: Thu, 11 Jul 2019 21:06:51 +0200
>> From: Ergus <spacibba@aol.com>
>> Cc: emacs-devel@gnu.org
>>
>> Check if indenting with spaces or tabs && add the indicator for
>> those character (or every tab-width spaces) from the beginning of the line
>> until the first different character of the line. And that's it...
>
>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)

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.

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?