display word wrapping

[Miles Bader <miles@lsi.nec.co.jp>]

Using variable-width fonts more regularly has gotten me musing about
display word-wrapping support (for the next version, not this one :-).

I've always thought that since the display engine does `proper' wrapping
for variable-width characters already (variable-width fonts, tabs, etc),
which really seems to work awful darn well, maybe it wouldn't be too
hard to trick it into treating words in the buffer as `characters' for
wrapping purposes.  That seems like it might make everything just work
correctly.

What I'm wondering is what other support, besides the basic `wrap lines
at word boundaries' is needed.

  * A text-property that defines left/right margins -- with display
    wrapping the window boundary is probably not exactly right,
    you often want some whitespace in there.

  * A way to define how words are divided for the magic wrapping.  I
    suppose it should use syntax tables in some way; I'm not sure are
    they easy to use or not from the display engine's point of view?
    I'm thinking that to make things simple, you'd always want to wrap
    _after_ whitespace (so that it remains editable, but doesn't mess
    with your left margin)

  * You probably want to turn off the fringe wrapping glyphs, but maybe
    not the fringes...

  * Good support for display-oriented C-n/C-p (I'm not sure existing
    methods e.g using `vertical-motion' work well with variable-width
    characters)

What else?

Just babbling,

-Miles
-- 
Any man who is a triangle, has thee right, when in Cartesian Space, to
have angles, which when summed, come to know more, nor no less, than
nine score degrees, should he so wish.  [TEMPLE OV THEE LEMUR]