Re: Developing a new text editor widget?

[Simon McVittie <simon mcvittie collabora co uk>]

On Sat, 11 Jun 2016 at 11:47:25 +0200, Sébastien Wilmet wrote:
> On Sun, Jun 05, 2016 at 12:33:20PM -0700, Christian Hergert wrote:
> > Are there situations where the character is larger than a single cell?
>
> Yes I think.
>
> In French there is æ and œ, those should ideally be displayed as 1.5x
> the size of a char. Or there is also "…". But those are still entirely
> readable in monospace. But I think in other languages, there are
> characters that should take 2x the size of a cell.

Monospace environments like terminals traditionally display æ, œ, … as
a single character-cell: it isn't typographically correct, but neither
is having m the same width as i, and we tolerate that in monospace.

The one use I'm aware of for characters that occupy more than one cell
in monospace is that CJK writing systems have the concept of "fullwidth"
character forms. which take up 2 adjacent cells.
<https://en.wikipedia.org/wiki/Halfwidth_and_fullwidth_forms>

For instance, if you read this mail in monospace, these lines should
line up exactly, even though in a proportional font they'd be very
different lengths:

    |Ｆｕｌｌｗｉｄｔｈ|
    |halfwidthhalfwidth|
    |朅—∴mw朅—∴mw朅—|
    |iiiiiiiillllllllll|

(It works as described in gnome-terminal, xterm and gvim, but not in
gedit, where the full-width letters are about 1.5 character cells.)

    S