Coloring should be disabled if output is not a TTY

[meowgorithm]

It's sort of opposite the point of this library, but with things like the auto-fetch-from-github functionality users could find themselves doing something like the following:

gold -s dark.json https://github.com/muesli/beehive | less

…which of course would appear littered with ASCII escape codes.

[muesli]

Good point, let me fix that.

[CallumHoward]

Could this have an optional flag to force colors? I would like to use glow to preview markdown files in ranger but the colours get stripped.

[muesli]

@CallumHoward You can explicitly set a style to enforce it: glow -s dark | less -r for example.

[CallumHoward]

Amazing, thanks!

[eric-saintetienne]

That's not the same output though.

With -s dark I get this output:

But when -s dark stdout is piped I get a different output (I used cat but it's the same with less, even with the -R argument):

I've tried to force stdout being a tty through unbuffer (part of the expect package) which provides a tty to stdout but then the behaviour is terrible: glow takes about 10 seconds to complete and extra garbage is output.

In summary, there's something wrong with the implementation of how tty is handled:

1. using a style doesn't render the same output when a tty is present (or not)
2. glow takes a very long time to complete and outputs extra garbage when a tty is emulated via unbuffer.

[eric-saintetienne]

@muesli can you please re-open this ticket? Thanks.

[meowgorithm]

Hey everyone. I can look into this one. This is the same issue as #654, right? If so, let’s track it there.

[eric-saintetienne]

Yes it seems to be the same issue. The ticket #654 is more recent but that shouldn't be an issue as the current ticket is closed.

Thanks for looking into it.

[meowgorithm]

Awesome, sounds good. Let’s track the issue there, then.

[nikelborm]

I also made my ugly hack to force colors

Also takes a lot of time to do something, but at least I was able to remove the garbage:

script -q -c "glow README.md" | tail -n +2