HSL color invert support?

[SuperCowProducts]

test.pdf

test.typ

#import "@preview/pigmentpedia:0.3.3": *

#let cc = text.with(fill: black)
#let dd = text.with(fill: red)
#let oo = text.with(fill: orange)
#let yy = text.with(fill: iscc-nbs.vivid-yellow)
#let nn = text.with(fill: green)
#let bb = text.with(fill: dodgerblue)
#let pp = text.with(fill: rebeccapurple)
#let kk = text.with(fill: deeppink)
#let aa = text.with(fill: grey)
$
  cc(c)
  dd(c)
  oo(c)
  yy(c)
  nn(c)
  bb(c)
  pp(c)
  kk(c)
  aa(c)
$

zathurarc

set recolor true
set recolor-keephue "true"
set recolor-adjust-lightness

I have tried Chromium, Sioyek, Okular and katvan which all render these colors well, pointing to a zathura-specific issue.
(cfr. IgKh/katvan#32)

Is there a way to produce a similar effect in zathura, or does it need to be coded?

In particular @sebastinas I have seen you have discussed dark theme in multiple issues, are you aware of what might be going on?

Also @MithicSpirit, since you worked on recolor-adjust-lightness (#745), do you think this would require another option?

Thanks!

[MithicSpirit]

I'm not sure what the issue even is. Can you send screenshots of what you're seeing and what you expect to be seeing?

[SuperCowProducts]

Sure,

this is what I see in Okular:

and this is what I see in Zathura:

Do you see what I mean now? It seems like Zathura is using a unique filter which may work particularly well on certain documents, although doesn't work for when you want to color-code a document while writing.

[MithicSpirit]

Try not setting recolor-adjust-lightness (you can interactively toggle it at runtime with :set recolor-adjust-lightness). That deliberately increases the lightness, which makes colors look washed out.

[SuperCowProducts]

Thanks, it is better without. Although it is still an algorithm which doesn't play well with my selection of colors:

[MithicSpirit]

Yeah, it does appear like the Okular algorithm is a bit better. I'm not going to speak for Sebastian, but imo introducing yet another knob for this is too much; I think it would be better to just change the existing algorithm (although I'd like for it to be tested on a variety of documents to make sure it works well across the board).

[SuperCowProducts]

keep in mind as stated in IgKh/katvan#32 HSL is actually pretty widely used for dark theme across readers (as I tested myself), so actually there is likely to be a ready-made implementation Zathura can just plug in, without needing to reinvent too much :)

[sebastinas]

I don't see an algorithm there. HSL is a colorspace.

[SuperCowProducts]

@sebastinas my bad, hopefully the title makes more sense now

[sebastinas]

No, what is "standard HSL color invert?" If there is a standard, surely this documented somewhere.

[SuperCowProducts]

Yeah I think that bit is also unnecessary. I sort of assumed it was standard since all other apps with support for rendering PDFs that I tested behaved in the same way.

[sebastinas]

I'll leave this tagged as 'question' until somebody can provide the algorithm.

[MithicSpirit]

I'd suggest checking the source code for okular/sioyek/katvan, but these are all GPL, so we couldn't use it here. Checking the source code for chromium is still an option, but I don't feel like trawling through that.