Enabling truncate-lines on a per-line basis

Enabling truncate-lines on a per-line basis

[Matthew Dempsky]

I've been hacking up org-indent.el into a new minor-mode that smartly
wraps lists and outline headers (by appropriately setting
`wrap-prefix') so it can play nicely with visual-line-mode.  However,
I'd still like large tables to be truncated rather than wrapped.

Is there currently a way to selectively enable truncation on certain
lines, but leave it disabled on others?

Re: Enabling truncate-lines on a per-line basis

[Matthew Dempsky]

On Wed, Dec 2, 2009 at 7:03 PM, Matthew Dempsky <matthew@dempsky.org> wrote:
> Is there currently a way to selectively enable truncation on certain
> lines, but leave it disabled on others?

Looking at xdisp.c, it looks like there's no elisp solution to setting
line_wrap == TRUNCATION on a per-line basis, and even if there was, it
looks like more of the display algorithm would need reworking to
support it.

Oh well.

Re: Enabling truncate-lines on a per-line basis

[Kevin Rodgers]

Matthew Dempsky wrote:
> On Wed, Dec 2, 2009 at 7:03 PM, Matthew Dempsky <matthew@dempsky.org> wrote:
>> Is there currently a way to selectively enable truncation on certain
>> lines, but leave it disabled on others?
> 
> Looking at xdisp.c, it looks like there's no elisp solution to setting
> line_wrap == TRUNCATION on a per-line basis, and even if there was, it
> looks like more of the display algorithm would need reworking to
> support it.

Maybe you could set the display text property on each line (starting
just before the right margin), to emulate truncate-lines.

If that works, you might be able to set the property via font-lock.

-- 
Kevin Rodgers
Denver, Colorado, USA

Re: Enabling truncate-lines on a per-line basis

[Matthew Dempsky]

On Thu, Dec 3, 2009 at 8:23 PM, Kevin Rodgers <kevin.d.rodgers@gmail.com> wrote:
> Maybe you could set the display text property on each line (starting
> just before the right margin), to emulate truncate-lines.

Nope, text from the 'display' property text still wraps. Also, you
can't navigate through it with the point. :(

Re: Enabling truncate-lines on a per-line basis

[Eli Zaretskii]

> Date: Thu, 3 Dec 2009 21:51:25 -0800
> From: Matthew Dempsky <matthew@dempsky.org>
> 
> you can't navigate through [`display' text property] with the point. :(

Yes, you can, although not easily (and perhaps it won't do exactly
what you want).  See the description of the `cursor' property in the
ELisp manual.

Re: Enabling truncate-lines on a per-line basis

[Kevin Rodgers]

Matthew Dempsky wrote:
> On Thu, Dec 3, 2009 at 8:23 PM, Kevin Rodgers <kevin.d.rodgers@gmail.com> wrote:
>> Maybe you could set the display text property on each line (starting
>> just before the right margin), to emulate truncate-lines.
> 
> Nope, text from the 'display' property text still wraps. Also, you
> can't navigate through it with the point. :(

I meant, if you want the buffer text truncated at column N, set the display
property at column N - 1 through the rest of the line to a single character
(e.g. U+2026 HORIZONTAL ELLIPSIS or U+22EF MIDLINE HORIZONTAL ELLIPSIS) to
indicate truncation.

-- 
Kevin Rodgers
Denver, Colorado, USA

Re: Enabling truncate-lines on a per-line basis

[Matthew Dempsky]

On Sat, Dec 5, 2009 at 12:16 AM, Kevin Rodgers
<kevin.d.rodgers@gmail.com> wrote:
> I meant, if you want the buffer text truncated at column N, set the display
> property at column N - 1 through the rest of the line to a single character
> (e.g. U+2026 HORIZONTAL ELLIPSIS or U+22EF MIDLINE HORIZONTAL ELLIPSIS) to
> indicate truncation.

Ohh, I see...  interesting idea!  I'll have to try this. :)

Thanks!

Re: Enabling truncate-lines on a per-line basis

[Stefan Monnier]

>>> Maybe you could set the display text property on each line (starting
>>> just before the right margin), to emulate truncate-lines.
>> Nope, text from the 'display' property text still wraps. Also, you
>> can't navigate through it with the point. :(
> I meant, if you want the buffer text truncated at column N, set the display
> property at column N - 1 through the rest of the line to a single character
> (e.g. U+2026 HORIZONTAL ELLIPSIS or U+22EF MIDLINE HORIZONTAL ELLIPSIS) to
> indicate truncation.

That can sadly be a lot more tricky that you'd like (even without
getting into proportional fonts, you have the problem of fixed-width
fonts but with varying facs giving varying font-sizes, or TABs, or \NNN
escape sequences, or images, or ...).


        Stefan

Re: Enabling truncate-lines on a per-line basis

[tomas]

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On Wed, Dec 02, 2009 at 07:03:29PM -0800, Matthew Dempsky wrote:
> I've been hacking up org-indent.el into a new minor-mode that smartly
> wraps lists and outline headers (by appropriately setting
> `wrap-prefix') so it can play nicely with visual-line-mode.  However,
> I'd still like large tables to be truncated rather than wrapped.
> 
> Is there currently a way to selectively enable truncation on certain
> lines, but leave it disabled on others?

There is a feature request "in-flight" for that:

  http://lists.gnu.org/archive/cgi-bin/namazu.cgi?query=%2Bmessage-id%3A<EC0D6A96-5F85-4083-BCF8-F005CEF950DF%40gmail.com>&submit=Search!&idxname=emacs-devel&max=20&result=normal&sort=score

(sorry for the long URL).

Regards
- -- tomás
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