Future of display engine and lines

[Alexandre Garreau <galex-713@galex-713.eu>]

I’ve a question.

Given these time I see some discussions about the display engine (notably 
faces, svg, pointer drawing, and more in-emacs GUI discussion, etc.), and 
I’ve already seen ---without prior work--- ambitious suggestions seriously 
made here before (like to make emacs a text processor on par with 
LibreOffice (or, who knows, GNU TeXmacs ;))), as well as ---without 
ambitious suggestion--- ambitious work seriously made such as integrating 
gtk widgets…

Given eww is pretty advanced for what it is (an one-man browser made as an 
extension (instead of the opposite) and likely one of the most advanced 
textual www browsers out there)…

How difficult would it be for emacs to support in-buffer multiple columns? 
such as LibreOffice would be able to.  Such as it is necessary for a more 
readable and usable web browser (eww actually supports columns but the 
same line of two different columns is on the same line of the buffer, so you 
cannot move linearly with text nor select consistently linear text (like 
on some broken pdf viewers)).  Such as it would make waaay more usable 
multiple-lines row in the org-mode tables.  Such as it would make reading 
on emacs, without having to use several windows, way more efficient compared 
with the useful usage ratio of the screen surface (given an optimal line 
is 66 chars or (unless reading boustrophedonly) moving eyes at each time 
because more tiring and make more time lost)?

Would it even be relevant? or would something such as “displaying one 
window/buffer inside another buffer/window” be more useful?

And how would it be to support multiple-lines inside one line, such as 
with fractions?  The concept looks similar to me: you need to cut a 
graphical line in the first case, and a logical one in the later.  I don’t 
know how the line/column/point-pos would be calculated in such a 
situation.  What I’d like is the ability to see a well-layouted fraction 
and at the same time moving the cursor inside it and editing/selecting 
parts of the text at the numerator or denominator, such as on scientifical 
calculators.  Currently that’s not possible even with org-mode latex-
fragments previews.

I have really hardly an idea of how would such a thing look, so I’m very 
curious about what more experienced and aknowledged-about-emacs-core 
people would think about it…