Does --theme=ansi improve performance?

[linrongbin16]

Does --theme=ansi improve bat performance?

[keith-hall]

I personally wouldn't expect it to make much difference, the same syntax highlighting engine is used, the same color scheme processing rules, just presumably with less colors. You can always benchmark it though.

[linrongbin16]

thanks

[sharkdp]

Well. Let's measure it:

hyperfine \
  --parameter-list theme default,ansi \
  --export-markdown=theme.md \
  'bat -f --theme={theme} jquery.js'

(I'm using the file tests/benchmarks/highlighting-speed-src/jquery.js from this repo)

Yes. bat is 25% faster when using the ansi theme:

Command	Mean [ms]	Min [ms]	Max [ms]	Relative
bat -f --theme=default jquery.js	655.7 ± 4.4	649.2	660.8	1.31 ± 0.01
bat -f --theme=ansi jquery.js	501.6 ± 3.3	498.1	509.2	1.00

That might come down to having less output to write(?). Because the ANSI escape sequences for a 24bit-color-theme are much longer.

I also ran a benchmark using hyperfines --show-output option, which measures the performance including the terminals rendering speed, because I suspected that might make a difference. But bat seems to be the limiting factor here. The results are pretty much the same as above.

[linrongbin16]

really thank for your benchmark!