Re: Emacs canvas support

[David Engster <david@engster.org>]

>> From: David Engster <deng@randomsample.de>
>> Date: Wed, 29 Apr 2020 18:14:55 +0200
>> Cc: Eli Zaretskii <eliz@gnu.org>, emacs-devel@gnu.org
>> 
>> [...] things like proper indentation guides, or widgets inside text
>> for code folding.
>
> Would it make sense to put these on the fringes?  If yes, this could
> be done without any changes on the C level, I think.

I just found that this exists already with the 'hideshowvis' package and
it works reasonably well. So I agree this is not a good use case.

You can also do indentation guides in current Emacs, but the packages I
tried did not work great. They usually collide with packages like
company-mode which are more important to me. This is often the case: if
you have several packages that use overlays and/or text properties for
fancy stuff, you can expect them to collide in some way.

Let's take another very simple example: I often wished it would be
possible to tell Emacs "Put an image at pixel position (x,y)" without
having to anchor it to some point position. For instance, I have a block
of text and would like to have an image next to it. Last I checked, the
only way to do this is to create a "sliced image" which automatically
gets cut up into rows and columns, but this is a very brittle workaround
(it doesn't work with an increased line-spacing, for instance).

-David