24 bit colour on TTYs -- make it customisable?

24 bit colour on TTYs -- make it customisable?

[Juliusz Chroboczek]

I've just had a look at commit e463e5, and it doesn't look like there's
a way to enable the support from .emacs.  Could somebody please add
a global variable or frame parameter that can be set from Lisp code to
enable 24-bit support?

Re: 24 bit colour on TTYs -- make it customisable?

[Eli Zaretskii]

> From: Juliusz Chroboczek <jch@irif.fr>
> Date: Sun, 19 Feb 2017 02:05:39 +0100
> 
> I've just had a look at commit e463e5, and it doesn't look like there's
> a way to enable the support from .emacs.  Could somebody please add
> a global variable or frame parameter that can be set from Lisp code to
> enable 24-bit support?

It is supposed to be enabled automatically.  Are you saying you want
to disable it?

Re: 24 bit colour on TTYs -- make it customisable?

[Juliusz Chroboczek]

>> I've just had a look at commit e463e5, and it doesn't look like there's
>> a way to enable the support from .emacs.  Could somebody please add
>> a global variable or frame parameter that can be set from Lisp code to
>> enable 24-bit support?

> It is supposed to be enabled automatically.  Are you saying you want
> to disable it?

I've only had a quick look at the code, but it's my understanding that
the feature is only enabled if terminfo has non-standard properties
setb24 and setf24.  Since it's easier to add a line to .emacs than
compiling a new terminfo, I'd like a way to enable the support without
hacking terminfo.

I'm definitely getting only 256 colours in a recent Debian testing XTerm.

-- Juliusz

Re: 24 bit colour on TTYs -- make it customisable?

[Rami Ylimäki]

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2017-02-20 22:30 GMT+02:00 Juliusz Chroboczek <jch@irif.fr>:

> I've only had a quick look at the code, but it's my understanding that
> the feature is only enabled if terminfo has non-standard properties
> setb24 and setf24.  Since it's easier to add a line to .emacs than
> compiling a new terminfo, I'd like a way to enable the support without
> hacking terminfo.
>

Using terminfo was the easiest way to implement this feature. I was told
earlier that the terminal-parameters alist could be useful for implementing
the configuration from elisp, but I never bothered to investigate that
option further.

I'm definitely getting only 256 colours in a recent Debian testing XTerm.
>

XTerm approximates 24-bit colors using the palette of 256 color mode.

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Re: 24 bit colour on TTYs -- make it customisable?

[Eli Zaretskii]

> From: Juliusz Chroboczek <jch@irif.fr>
> Date: Mon, 20 Feb 2017 21:30:09 +0100
> 
> I've only had a quick look at the code, but it's my understanding that
> the feature is only enabled if terminfo has non-standard properties
> setb24 and setf24.  Since it's easier to add a line to .emacs than
> compiling a new terminfo, I'd like a way to enable the support without
> hacking terminfo.

We don't support such methods with any other color modes, they all
rely on terminfo and/or special-purpose terminal commands Emacs issues
at startup time.

I agree that being able to enable/disable color modes from .emacs
would be a nice feature, if it is possible, but the new 24-bit color
mode is not the odd one out here.

> I'm definitely getting only 256 colours in a recent Debian testing XTerm.

I don't think that xterm supports this mode.