Re: [Emacs-diffs] /srv/bzr/emacs/trunk r103444: * lisp/facemenu.el (list-colors-display): Use with-help-window (Bug#8048).

[Eli Zaretskii <eliz@gnu.org>]

> From: Chong Yidong <cyd@stupidchicken.com>
> Date: Mon, 28 Feb 2011 13:39:11 -0500
> Cc: Juanma Barranquero <lekktu@gmail.com>,
> 	Stefan Monnier <monnier@iro.umontreal.ca>,
> 	Emacs developers <emacs-devel@gnu.org>
> 
> martin rudalics <rudalics@gmx.at> writes:
> 
> >> Of course, another way to look at it is that the buffer's content should
> >> be independent from the window, and if it needs to be displayed
> >> differently according to the window size, then this should be done
> >> within the redisplay so that if that same buffer is displayed in several
> >> windows, they all look "right".  But the current redisplay features
> >> probably aren't sufficient for that.
> >
> > It's merely that code like `list-colors-print' would get confused.  We'd
> > have to run it for every window where the buffer is shown so an overlay
> > with a window property inserting the necessary amount of spaces would be
> > needed.
> 
> One possibility is to improve the redisplay engine to provide a way to
> specify a stretch glyph that stretches as far as possible.

I'm not following your line of thought -- is this about aligning
display of text "nicely" for the current window width?  If so, why a
display property whose value is like `(space :align-to POS)' or maybe
`(space :width WIDTH)' will not do this job?  Its implementation in
the display engine is exactly to produce a stretch glyph.  You can
even use something like `(0.4 . text)' to mean 40% of the width of the
text area, see the node "Pixel Specifications" in the ELisp manual.

If these facilities don't fit the bill, can someone explain what is
missing?

> The logic should be pretty similar to the implementation of word
> wrap, though I'm not sure how it would interact with word wrap, or
> with bidirectional display.

Bidirectional display simply lays out characters for display in the
order that is different from the logical (a.k.a reading) order they
are stored in the buffer.  Bidirectional display doesn't care a bit
about other display features that are produced from something other
than text.  Or am I missing something?