- From: Florian Rivoal via GitHub <sysbot+gh@w3.org>
- Date: Wed, 20 Mar 2024 17:40:08 +0000
- To: public-css-archive@w3.org
Here's a tentative summary of where we stand, based on the last call: While not directly the topic of this issue, there was a proposal made that might help with it, at least in part: that if a thumb color is provided, it applies no only to the thumb, but also to any control other than the thumb that might appear on the track, such as scroll-up or scroll-down buttons. (regardless of the rest, I'm in favor of adopting this part) As for the main question of this issue, I think the options being considered are: **1a.** specify that both thumb and track do respect transparency, without precomposition, (and so the track shows through the thumb and the background shows through the track); also special-case a fully transparent thumb and track to make the entire scrollbar invisible, even if it includes parts that are not otherwise colored (shading, texture, highlights, additional controls besides the thumb…) **1b.** specify that both thumb and track do respect transparency, without precomposition; also that their alpha channel is also applied to the non-colored parts of the scrollbar. I think this is equivalent to saying that thumb and track are first colored ignoring the alpha channel, then the alpha channel of the thumb/track color is applied to the whole thumb/track, including both colored and non colored parts. **2a.** Address scrollbar opacity through a separate `scrollbar-opacity` property; the alpha channel in `scrollbar-color` is ignored. **2b.** Address scrollbar opacity through a separate `scrollbar-opacity` property; the alpha channel in `scrollbar-color` is precomposed (presumably over the named [`canvas`](https://drafts.csswg.org/css-color-4/#valdef-color-canvas) color, although we didn't spend much time discussing which color to precompose against). We also discussed a "don't specify" option, but consider if off the table, because (at least) I would object to that: we cannot task authors with ensuring good contrast if they cannot know whether `transparent` will mean invisible (non-precomposed), black (ignore alpha), white (precompose against white)… Personally, I'm in favor of 2b. -- GitHub Notification of comment by frivoal Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/9853#issuecomment-2010201062 using your GitHub account -- Sent via github-notify-ml as configured in https://github.com/w3c/github-notify-ml-config
Received on Wednesday, 20 March 2024 17:40:09 UTC