From: Marcin Borkowski <mbork@mbork.pl>
To: "andlind\@gmail.com" <andlind@gmail.com>
Cc: help-gnu-emacs@gnu.org
Subject: Re: What happens with text properties in batch mode?
Date: Sat, 08 Dec 2018 21:08:53 +0100 [thread overview]
Message-ID: <87h8fnrdbe.fsf@mbork.pl> (raw)
In-Reply-To: <aef278e7-94ff-40f0-8387-f2952a348a15@googlegroups.com>
On 2018-12-08, at 19:31, andlind@gmail.com <andlind@gmail.com> wrote:
> On Friday, 7 December 2018 08:58:38 UTC+1, Marcin Borkowski wrote:
>
>> it seems that when I `princ' something with text properties (e.g.,
>> colored faces) in batch mode, the colors disappear. Is it documented
>> anywhere? Can I disable this behavior?
>
> Can you tell me what you are trying to accomplish? Simply printing a highlighted text stdout and expecting it to be shown with colors doesn't work.
I was just curious what happens to the properties after princ.
>> I found this: https://github.com/Lindydancer/e2ansi, and its existence
>> suggests that outputting colored stuff (using ANSI codes) is
>> non-trivial. Am I right?
>
> It is non-trivial, I can assure you, I spent many months writing it.
>
> One problem is that even though strings have face properties in batch mode, the faces themselves often fail to specify anything useful in batch mode. e2ansi contains a system for playing the "what if" game by allowing you to query things like "what would face X look like when in a gui with 16 millions colors, or in a black-and-white tty". (This part is placed in a stand alone library "face-explorer", along with tons of useful tools.)
>
> The second problem is to translate the face information to ANSI. Note that Emacs internal system for rendering things in terminal mode is not available to elisp, so I had to implement everything from scratch.
>
> Fortunately, you can use e2ansi as a library in your own packages. For example `e2ansi-string-to-ansi' converts a string with face information to ANSI. See `face-explorer-number-of-colors' and friends to control which features of ANSI will be used. (They have sane defaults, though.)
Thanks a lot for the details (and for e2ansi)! I'll try to look into it some day.
Best,
--
Marcin Borkowski
http://mbork.pl
next prev parent reply other threads:[~2018-12-08 20:08 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <mailman.5310.1544169515.1284.help-gnu-emacs@gnu.org>
2018-12-08 18:31 ` What happens with text properties in batch mode? andlind
2018-12-08 20:08 ` Marcin Borkowski [this message]
2018-12-07 7:56 Marcin Borkowski
2018-12-07 8:42 ` tomas
2018-12-08 19:28 ` Marcin Borkowski
2018-12-08 22:02 ` tomas
2018-12-07 9:05 ` Eli Zaretskii
2018-12-08 19:29 ` Marcin Borkowski
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