take into account the system theme #61236

GuillaumeGomez · 2019-05-27T14:00:26Z

The CSS can now take into account the system theme. I used it to generate some content on the document and from there, if no theme has already been selected, it'll look at the system level theme.

r? @QuietMisdreavus
cc @fenhl

fenhl · 2019-05-27T14:15:36Z

How does this interact with having set the theme manually? I switch my system theme between light and dark mode based on time of day and would like rustdoc to adhere to that.

fenhl · 2019-05-27T14:16:28Z

Looking at the changes, it seems that I'd just have to clear local storage. I'm okay with that.

GuillaumeGomez · 2019-05-27T18:27:10Z

You'd still have to reload the page, but that's a browser limitation (and I don't want to check multiple times after the page has been loaded if the theme hasn't change...).

bjorn3 · 2019-05-28T09:47:07Z

src/librustdoc/html/static/rustdoc.css

@@ -54,6 +54,21 @@
 		  box-sizing: border-box;
 }

+/* This part handles the "default" theme being used depending on the system one. */
+html {
+	content: "";


Maybe use a custom css property instead: https://developer.mozilla.org/en-US/docs/Web/CSS/--*

You mean CSS variable? Not supported on IE so we can't use it.

IE doesn't support prefers-color-scheme anyway. IE would not set the custom property to any value, but the javascript has a fallback for that already.

I'd prefer avoid potential failures if possible.

Just to confirm, since string values for content is only ever allowed for ::before and ::after, this won't cause a situation where the entire page is replaced with whatever is set here? MDN seems to imply this, but i want to double-check that that's what's actually going on.

The content is a hack that isn't displayed on this tag. You can only "see" it with js (I think it's because it's not a ::before or ::after element).

What are the chances of this behavior changing in the future? I don't want to be trapped in a situation where the CSS spec starts allowing element replacement with strings, and a whole bunch of docs are rendered unusable because we started depending on this workaround.

I'm not sure to follow you. There is nothing in the specs or anywhere changing this behavior for the moment and if there is any change, we'll have quite a lot of time before needing to update it. Also, what are you referring to when talking about "and a whole bunch of docs are rendered unusable because we started depending on this workaround."?

If this behavior changes, i.e. some browser decides that setting content to a string on an element will cause the element to be replaced by that string, then any documentation already built by a rustdoc using this CSS will only display the string set here.

As long as the specs are on our side, and setting content to a string on an element does nothing, then i think i can be okay with this.

QuietMisdreavus

This PR seems fine, just one naming nit.

Would it be worth checking for whether it's set and adding a "system" entry to the drop-down that clears the local storage and loads the prefers-color-scheme value? I'm not sure how many people would be willing to dive into browser dev tools to clear the theme value.

QuietMisdreavus · 2019-06-05T21:08:54Z

src/librustdoc/html/static/storage.js

@@ -88,7 +88,7 @@ function getCurrentValue(name) {
    return null;
 }

-function switchTheme(styleElem, mainStyleElem, newTheme) {
+function switchTheme(styleElem, mainStyleElem, newTheme, dontSaveNewValue) {


I'm a bit wary of naming the parameter "don't save new value", just because it feels weird to name a boolean parameter after the opposite of what it does. Maybe something like initialLoad or skipStorage? Or even inverting the value that is sent on the initial call and calling it persist?

I like skipStorage! Let's go for it! :)

QuietMisdreavus · 2019-06-05T21:23:04Z

src/librustdoc/html/static/rustdoc.css

@@ -54,6 +54,21 @@
 		  box-sizing: border-box;
 }

+/* This part handles the "default" theme being used depending on the system one. */
+html {
+	content: "";


Just to confirm, since string values for content is only ever allowed for ::before and ::after, this won't cause a situation where the entire page is replaced with whatever is set here? MDN seems to imply this, but i want to double-check that that's what's actually going on.

GuillaumeGomez · 2019-06-06T08:30:38Z

@QuietMisdreavus: I'm not sure it's worth it to add a system theme entry. It's just in case you didn't set your theme after all, and since it's locally stored, if you change of computer it'll just pick a theme depending on your system theme.

GuillaumeGomez · 2019-06-06T08:50:11Z

Updated!

QuietMisdreavus · 2019-06-06T15:36:32Z

@QuietMisdreavus: I'm not sure it's worth it to add a system theme entry. It's just in case you didn't set your theme after all, and since it's locally stored, if you change of computer it'll just pick a theme depending on your system theme.

I'm not sure what you mean by "change of computer". My concern is that people who have already set a theme on doc.rust-lang.org won't have the option of using the system theme as a default without clearing their browser history or manually digging into developer tools to fiddle with specific Local Storage values. Since we've had themes available on that domain for a long time now, it's very likely that users will already have a theme setting saved. The same goes for docs.rs.

GuillaumeGomez · 2019-06-06T20:34:30Z

Why would you want to use it system theme if you already set it yourself? I'm not sure to follow on this one...

QuietMisdreavus · 2019-06-06T22:02:23Z

Why would you want to use it system theme if you already set it yourself? I'm not sure to follow on this one...

What if you decide you wanted to change your system theme? What if you have your system theme change on different times of day (e.g. to track sunset and sunrise, or to differentiate between "work mode" and "personal mode", etc)? All of our current users have already set a theme choice, and may want to start taking advantage of this feature once it lands.

GuillaumeGomez · 2019-06-06T22:19:39Z

Sounds weird to change the website design when switching pages though. Hummm... I don't want to add the "system theme" entry but I don't really know what to do for this one...

Dylan-DPC-zz · 2019-07-01T15:29:19Z

ping from triage @QuietMisdreavus any updates on this?

src/librustdoc/html/static/storage.js

totsteps · 2019-07-23T18:05:41Z

ping from triage, @QuietMisdreavus any updates on this?

fmckeogh · 2019-07-31T09:05:01Z

Second ping from wg-triage, pinging random member of Rustdoc.

@ollie27

GuillaumeGomez · 2019-07-31T09:28:38Z

It's been around for a while and I resolved all issues (as long as the users don't change the theme by themselves, it won't be set in the local storage so changing page will still rely on the system theme).

I'll wait to see if @ollie27 has anything to say.

fmckeogh · 2019-07-31T09:31:47Z

Ah sorry, my bad, I wasn't sure if the final concern was blocking or not.

GuillaumeGomez · 2019-07-31T13:49:03Z

If you're talking about window.matchMedia, it can't be added because not supported in old browsers (but very interesting more new projects of mine!).

dima74 · 2019-08-03T22:12:47Z

@GuillaumeGomez may I ask, which old browsers did you mean? I don't know exactly policy about browsers (best what I found is this rfc), but looks like window.matchMedia has strong browser support:

GuillaumeGomez · 2019-08-03T22:40:18Z

We unofficially support rustdoc starting IE9. I think I'll drop it not too far in the future though.

JohnTitor · 2019-08-11T13:52:54Z

Ping from triage: @QuietMisdreavus @ollie27 waiting on your review

bjorn3 · 2019-08-20T12:59:28Z

@Chocol4te I am not a rust-lang member.

fmckeogh · 2019-08-20T13:01:10Z

@bjorn3 I'm very sorry, I saw the Reviewers tab and mistakenly assumed you were

GuillaumeGomez · 2019-08-20T13:02:29Z

r? @Mark-Simulacrum

Mark-Simulacrum · 2019-08-20T16:00:31Z

src/librustdoc/html/static/storage.js

-        updateLocalStorage("rustdoc-theme", newTheme);
+        // If this new value comes from a system setting or from the previously saved theme, no
+        // need to save it.
+        if (skipStorage !== true) {


Could we make this a positive variable instead of skip? So that the if could become if (saveTheme) { ... }

src/librustdoc/html/static/storage.js

Mark-Simulacrum · 2019-08-20T16:04:23Z

As to allowing users to say "go with whatever the system does" after having configured something, it does seem like we could always add that functionality at a later point -- there's no need to block this PR on that then. I agree with @GuillaumeGomez that it seems like a fairly unusual desire (but I don't know anyone who changes system themes often...)

GuillaumeGomez · 2019-08-21T10:50:23Z

@Mark-Simulacrum Applied the change you suggested.

Mark-Simulacrum · 2019-08-21T11:02:56Z

@bors r+

Looks good to me!

bors · 2019-08-21T11:02:57Z

📌 Commit 1bd9424 has been approved by Mark-Simulacrum

@QuietMisdreavus

…-Simulacrum take into account the system theme Fixes rust-lang#61079. The CSS can now take into account the system theme. I used it to generate some content on the document and from there, if no theme has already been selected, it'll look at the system level theme. r? @QuietMisdreavus cc @fenhl

@ghost

Rollup of 6 pull requests Successful merges: - #61236 (take into account the system theme) - #63717 (Fix nested eager expansions in arguments of `format_args`) - #63747 (update Miri) - #63772 (ci: move libc mirrors to the rust-lang-ci-mirrors bucket) - #63780 (Improve diagnostics: break/continue in wrong context) - #63781 (Run Clippy without json-rendered flag) Failed merges: r? @ghost

fenhl · 2019-08-22T07:48:37Z

Unfortunately, it doesn't seem to be working. Inspector is showing content: "dark"; in the styles for the <html> tag, and local storage is empty, but I'm still seeing the light theme. (This is on a file: URL, haven't tested https: since docs.rs isn't updated yet.)

GuillaumeGomez · 2019-08-22T11:31:04Z

Give it a try on https://doc.rust-lang.org/nightly/std

fenhl · 2019-08-23T06:10:05Z

Same there.

GuillaumeGomez · 2019-08-23T09:29:58Z

Can you open an issue so I can add it to my todo list please?

rust-highfive assigned QuietMisdreavus May 27, 2019

rust-highfive added the S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. label May 27, 2019

bjorn3 reviewed May 28, 2019

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QuietMisdreavus reviewed Jun 5, 2019

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GuillaumeGomez force-pushed the system-theme branch from 3dcca5f to a050d2a Compare June 6, 2019 08:50

dima74 reviewed Jul 7, 2019

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src/librustdoc/html/static/storage.js Show resolved Hide resolved

rust-highfive assigned Mark-Simulacrum and unassigned QuietMisdreavus Aug 20, 2019

Mark-Simulacrum reviewed Aug 20, 2019

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GuillaumeGomez added 2 commits August 21, 2019 10:08

take into account the system theme

c076d30

Replaced skipStorage with saveTheme variable

1bd9424

GuillaumeGomez force-pushed the system-theme branch from a050d2a to 1bd9424 Compare August 21, 2019 10:49

bors added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Aug 21, 2019

Centril mentioned this pull request Aug 21, 2019

Rollup of 6 pull requests #63790

Merged

bors merged commit 1bd9424 into rust-lang:master Aug 21, 2019

GuillaumeGomez deleted the system-theme branch August 22, 2019 11:30

fenhl mentioned this pull request Aug 23, 2019

Automatic dark theme doesn't work #63830

Closed

fenhl mentioned this pull request Sep 1, 2019

Automatic dark theme still doesn't work #64061

Closed

take into account the system theme #61236

take into account the system theme #61236

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GuillaumeGomez commented May 27, 2019

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GuillaumeGomez commented Jun 6, 2019

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