[konsole] [Bug 401094] Malayalam rendering regression in Konsole 18.08

[Mariusz Glebocki]

https://bugs.kde.org/show_bug.cgi?id=401094

--- Comment #15 from Mariusz Glebocki <mglb at arccos-1.net> ---
Created attachment 124656
  --> https://bugs.kde.org/attachment.cgi?id=124656&action=edit
render preview (2019-12-22)

(In reply to Rajeesh K V from comment #12)
> (In reply to Mariusz Glebocki from comment #11)
> 
> > 
> > I've attached a patch which renders provided example almost as intended.
> > Each word is rendered separately and spacing is wrong, but it can be fixed
> > later. Apply with `patch -p1 < malayalam-rendering-poc.patch` in top level
> > Konsole directory.
> 
> Applied the patch over konsole-19.12.0 source and tested the rendering.
> Comparing with rendering of 18.08, there is improvement (see attached
> screenshot), but not fully fixed.

Oops! Right. Working version here:
https://invent.kde.org/mglebocki/konsole/tree/wip/complex-scripts-support
There's also a commit which render debug rectangles/tooltips - just skip/remove
it if you want to build Konsole for regular use.


> Historically, only Konsole ≤ 17.12 handled Indic scripts well. GNOME
> Terminal and other terminals never properly rendered those. Also, Emacs
> shapes and renders complex scripts very well, but to my knowledge it uses a
> different library.

Terminal version of emacs, or the one with its own window? The latter does not
have terminal limitations.


> Not only Malayalam (the patch checks for Unicode range 0D00–0D7F) but all
> complex scripts including dozens of Indic scripts, Sinhala, South/East Asian
> scripts etc. all would need similar support.

That's something to do later. Ideally it would just need adding additional
ranges.


> > * Is there some simplified/alternative way to display the script?
> 
> Not sure I understand the question, could you elaborate?

Kind of like 'ae' can be used instead of 'æ' when there are technical
limitations.
I didn't find anything like this for Malayalam, so I guess that's not the case
here.


> > * Are there (console) programs which actually use the script? What are
> > real-world use cases?
> 
> Just like Latin scripts, complex scripts are used by millions of people on a
> daily basis.

I mean, some console programs which use complex scripts in its interface,
preferably something more advanced than just printing line of text. They would
be useful as test cases. So far I'm testing mc with file names written in
Malayalam.

https://phabricator.kde.org/F7831279


(In reply to Subin from comment #14)
> (In reply to Mariusz Glebocki from comment #11)
> 
> > * Rename "Bi-directional text rendering" option to something like "Support
> > for complex scripts" and enable special rendering for complex scripts like
> > Malayalam when it is enabled. RTL scripts already have the same problems, so
> > users wouldn't be suprised. This solution has the same issues as previous
> > one, but it's already there.
> 
> Where is this option located ? Would enabling that now improve the current
> display of malayalam characters ?

It is not there yet, but I'll add it to Edit Profile → Advanced.


> > * Are there (console) programs which actually use the script? What are
> > real-world use cases?
> 
> My usecase is editing malayalam text files with nano.

This might be hard to do - nano must support it, otherwise it will be moving
cursor incorrectly.

-- 
You are receiving this mail because:
You are the assignee for the bug.