Add lineHighlight for ansi theme

[jsit]

The ansi theme doesn't have lineHighlight defined, so the highlighted line is not apparent.

[sharkdp]

Thank you for reporting this! Should be easy to fix, I hope.

[jsit]

Well what I realized is that no single color will work well, depending on whether a user has a light or dark background. I imagine this is part of why there were once separate ansi-dark and ansi-light themes.

[sharkdp]

FYI @mk12: again, only if you are interested(!).

[mk12]

Can you share an example of when bat would use this? I'm not sure when a line would be highlighted.

[sharkdp]

Ah, yes. Sorry. Whenever someone uses the --highlight-line option:

    -H, --highlight-line <N:M>...        Highlight lines N through M.

For example:

seq 10 | bat --highlight-line 3:5

[mk12]

Thanks for the example, I didn't know about that.

Even if ansi-light and ansi-dark were still separate I don't think there's any good color for this in a typical 8 color palette. For example if you choose yellow then foreground yellow text becomes invisible. You could choose from the 256-color palette but that defeats the purpose of ansi being restricted to the 8 color palette.

I'd suggest using bold (already supported I believe) or reverse video (would need to use another alpha channel pattern to encode it). What do you think?

[jsit]

What's the support for underline like? I imagine it's less common in terminal emulator than bold.

[sharkdp]

What's the support for underline like? I imagine it's less common in terminal emulator than bold.

Yes, definitely.

Let's try this out.

[mdibaiee]

Hey 👋
I just made an attempt to fix this, but I'm not sure if what I've done is the best way to do it... (I have an ugly hardcoded condition for ANSI...)

Another way to do it would be to use a custom theme scope, e.g.:

<dict>
    <key>name</key>
    <string>Line highlight style</string>
    <key>scope</key>
    <string>line_highlight</string>
    <key>settings</key>
    <dict>
        <key>font_style</key>
        <string>italic</string>
    </dict>
</dict>

What do you think?

Update: I implemented the custom scope solution and committed it on top of my MR. There are two commits now each with one of the approaches. Let me know what you think and I can squash to the final solution.