[css-overflow-4] Draft spec for `continue: collapse` (#7708) #10816

andreubotella · 2024-09-02T11:59:52Z

No description provided.

bfgeek · 2024-09-17T16:26:07Z

@emilio - Does this look reasonable to you?

andreubotella · 2024-10-03T23:38:55Z

Before now, this PR allowed clamping between any two blocks, to make it closer to the continue: discard behavior, but in hallway conversations in TPAC we agreed that having it clamp to the last line before clamp, even if there are lineless boxes after it that will still fit, was a better behavior. I just updated the spec text to reflect this.

tabatkins · 2024-10-04T17:51:41Z

but in hallway conversations in TPAC we agreed that having it clamp to the last line before clamp, even if there are lineless boxes after it that will still fit, was a better behavior

In particular, the argument was that auto clamping should be equivalent to the largest <integer> clamp that avoids overflow; it's weird if auto actually lets you include an amount of content between two <integer> values, and thus can't be reproduced directly.

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1791226 gecko-commit: c6ce92301ca11292a5dd25f07a80243592c94e5a gecko-reviewers: layout-reviewers, dshin

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1791226 gecko-commit: cf9f54eef33465d089f850a55da5734a911fdac4 gecko-reviewers: layout-reviewers, dshin

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 bugzilla-url: https://bugzilla.mozilla.org/show_bug.cgi?id=1791226 gecko-commit: cf9f54eef33465d089f850a55da5734a911fdac4 gecko-reviewers: layout-reviewers, dshin

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 UltraBlame original commit: c6ce92301ca11292a5dd25f07a80243592c94e5a

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 UltraBlame original commit: cf9f54eef33465d089f850a55da5734a911fdac4

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 UltraBlame original commit: c6ce92301ca11292a5dd25f07a80243592c94e5a

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 UltraBlame original commit: cf9f54eef33465d089f850a55da5734a911fdac4

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 UltraBlame original commit: c6ce92301ca11292a5dd25f07a80243592c94e5a

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578 UltraBlame original commit: cf9f54eef33465d089f850a55da5734a911fdac4

This matches the proposal in w3c/csswg-drafts#10816, and creates much better behavior. Differential Revision: https://phabricator.services.mozilla.com/D157578

frivoal

This seems mostly good. I've made a few small suggestion for normative changes, and more suggestions for editorial changes (most of which are about source formatting).

Most of the remaining issues are orthogonal to this PR, so I think we can merge first and keep working on those later, as soon as the comments on this PR are addressed.

frivoal · 2024-11-04T02:20:22Z

css-overflow-4/Overview.bs

 	that would receive subsequent content,
 	then the content displaced by the <a>block overflow ellipsis</a>
-	must be pushed to that <a>fragmentation container</a>.
+	must be pushed to that <a>fragmentation container</a>. If it is placed before a [=clamp point=],


Editorial:

Suggested change

must be pushed to that <a>fragmentation container</a>. If it is placed before a [=clamp point=],

must be pushed to that <a>fragmentation container</a>.

If it is placed before a [=clamp point=],

Reason: this spec uses semantic line-breaks, and I'd prefer to stay consistent with that. See https://rhodesmill.org/brandon/2012/one-sentence-per-line/

frivoal · 2024-11-04T02:23:20Z

css-overflow-4/Overview.bs

 	that would receive subsequent content,
 	then the content displaced by the <a>block overflow ellipsis</a>
-	must be pushed to that <a>fragmentation container</a>.
+	must be pushed to that <a>fragmentation container</a>. If it is placed before a [=clamp point=],
+	then the displaced content must be pushed to the remainder of the [=inline formatting context=].


I'm ok with that, but I think this has been controversial, with some advocating that the displaced content be dropped / invisible instead, in order to avoid that inserting the ellipsis would cause an extra layout pass. Should we open a separate issue to discuss that aspect?
Or maybe this is unavoidable due to bidi processing of the ellipsis, which means we have to relayout anyway?

frivoal · 2024-11-04T02:30:37Z

css-overflow-4/Overview.bs

@@ -844,7 +849,7 @@ Limiting Visible Lines: the 'line-clamp' shorthand property</h3>
 		<dt><dfn><<integer [1,∞]>></dfn>
 		</dt><dfn><'block-ellipsis'></dfn>
 		<dd>
-			Sets 'continue' to ''discard''
+			Sets 'continue' to ''collapse''


Suggested change

Sets 'continue' to ''collapse''

Issue(7708): Whether this should imply ''discard'' or ''collapse'' is an unresolved question.

Sets 'continue' to ''collapse''

frivoal · 2024-11-04T02:37:29Z

css-overflow-4/Overview.bs

+	<var>N</var> is the computed value of 'max-lines':
+
+	- If the box is a [=fragmentation container=] that captures [=region breaks=],
+	    a <a>region break</a> or


Suggested change

a <a>region break</a> or

a <a>region break</a>

frivoal · 2024-11-04T02:39:00Z

css-overflow-4/Overview.bs

+	If the value of 'max-lines' is not <dfn for=max-lines dfn-type=value>none</dfn>, then, where
+	<var>N</var> is the computed value of 'max-lines':


Editorial:

Suggested change

If the value of 'max-lines' is not <dfn for=max-lines dfn-type=value>none</dfn>, then, where

<var>N</var> is the computed value of 'max-lines':

If the value of 'max-lines' is not <dfn for=max-lines dfn-type=value>none</dfn>,

then, given a [=computed value=] of <var>N</var>:

frivoal · 2024-11-04T03:31:57Z

css-overflow-4/Overview.bs

+	- A point immediately after a [=line box=] in the line-clamp container's [=block formatting
+	  context=].


Editorial

Suggested change

- A point immediately after a [=line box=] in the line-clamp container's [=block formatting

context=].

- A point immediately after a [=line box=]

in the line-clamp container's [=block formatting context=].

See https://rhodesmill.org/brandon/2012/one-sentence-per-line/

frivoal · 2024-11-04T03:32:54Z

css-overflow-4/Overview.bs

+	- The end of the line-clamp container, if there are any boxes after the last [=inline formatting
+	  context=] in the line-clamp container's [=block formatting context=].


Editorial

Suggested change

- The end of the line-clamp container, if there are any boxes after the last [=inline formatting

context=] in the line-clamp container's [=block formatting context=].

- The end of the line-clamp container,

if there are any boxes after the last [=inline formatting context=]

in the line-clamp container's [=block formatting context=].

See https://rhodesmill.org/brandon/2012/one-sentence-per-line/

frivoal · 2024-11-04T03:35:24Z

css-overflow-4/Overview.bs

+	Any boxes in a [=line-clamp container=] that follow its [=clamp point=] in the box tree, as well
+	as any [=line boxes=] that follow it inside an [=inline formatting context=], will be invisible
+	(behaving like ''visibility: hidden''). This includes [=independent formatting contexts=] as
+	well as [=out-of-flow=] boxes, and all of their descendants. Any overflow such boxes and line
+	boxes might have is always counted as [=ink overflow=] rather than [=scrollable overflow=].


Editorial

Suggested change

Any boxes in a [=line-clamp container=] that follow its [=clamp point=] in the box tree, as well

as any [=line boxes=] that follow it inside an [=inline formatting context=], will be invisible

(behaving like ''visibility: hidden''). This includes [=independent formatting contexts=] as

well as [=out-of-flow=] boxes, and all of their descendants. Any overflow such boxes and line

boxes might have is always counted as [=ink overflow=] rather than [=scrollable overflow=].

Any boxes in a [=line-clamp container=] that follow its [=clamp point=] in the box tree,

as well as any [=line boxes=] that follow it inside an [=inline formatting context=],

will be invisible (behaving like ''visibility: hidden'').

This includes [=independent formatting contexts=]

as well as [=out-of-flow=] boxes,

and all of their descendants.

Any overflow such boxes and line boxes might have

is always counted as [=ink overflow=] rather than [=scrollable overflow=].

See https://rhodesmill.org/brandon/2012/one-sentence-per-line/

frivoal · 2024-11-04T03:47:20Z

css-overflow-4/Overview.bs

+	If the [=line-clamp container=]'s [=block formatting context root=] has a [=computed value=] of
+	'max-lines' other than ''max-lines/none'', then that property will determine the [=clamp point=].
+	Otherwise, the clamp point will be set to the last possible clamp point such that, for it and
+	all previous possible clamp points, the line-clamp container's [=automatic block size=] (as
+	determined below) is not greater than the [=block size=] the box would have if its automatic
+	block size were infinite; or if that is not the case for any clamp points, to the first clamp
+	point in the block formatting context.


Editorial:

Suggested change

If the [=line-clamp container=]'s [=block formatting context root=] has a [=computed value=] of

'max-lines' other than ''max-lines/none'', then that property will determine the [=clamp point=].

Otherwise, the clamp point will be set to the last possible clamp point such that, for it and

all previous possible clamp points, the line-clamp container's [=automatic block size=] (as

determined below) is not greater than the [=block size=] the box would have if its automatic

block size were infinite; or if that is not the case for any clamp points, to the first clamp

point in the block formatting context.

If the [=line-clamp container=]'s [=block formatting context root=]

has a [=computed value=] of 'max-lines' other than ''max-lines/none'',

then that property will determine the [=clamp point=].

Otherwise, the clamp point will be set to the last possible clamp point

such that, for it and all previous possible clamp points,

the line-clamp container's [=automatic block size=]

(as determined below)

is not greater than the [=block size=] the box would have

if its automatic block size were infinite;

or if that is not the case for any possible clamp points,

to the first possible clamp point in the block formatting context.

See https://rhodesmill.org/brandon/2012/one-sentence-per-line/

I also added the word "possible" before "clamp point" in the last two lines.

frivoal · 2024-11-04T03:50:15Z

css-overflow-4/Overview.bs

+	This property only affects a line box if it immediately precedes
+	eiher a [=region break=] or a [=clamp point=] in the [=block formatting context=].
+	If the [=clamp point=] is placed at the end of the [=line-clamp container=], then the line will
+	not be affected.


Editorial

Suggested change

This property only affects a line box if it immediately precedes

eiher a [=region break=] or a [=clamp point=] in the [=block formatting context=].

If the [=clamp point=] is placed at the end of the [=line-clamp container=], then the line will

not be affected.

This property only affects a line box

if it immediately precedes eiher a [=region break=]

or a [=clamp point=] in the [=block formatting context=].

If the [=clamp point=] is placed at the end of the [=line-clamp container=],

then the line will not be affected.

Reason: this spec uses semantic line-breaks, and I'd prefer to stay consistent with that. See https://rhodesmill.org/brandon/2012/one-sentence-per-line/

frivoal · 2024-11-04T07:39:13Z

@tabatkins , for your comment in #10816 (comment), I'd suggest following up in #10868, because that aspect exists before this PR. The text of the spec may need to change depending on where we land on that issue (and others), but this PR isn't changing it, so I think we should take one problem at a time.

andreubotella added the css-overflow-4 label Sep 2, 2024

andreubotella requested review from frivoal and emilio September 2, 2024 11:59

bfgeek mentioned this pull request Sep 18, 2024

Unprefixed line-clamp web-platform-tests/interop#725

Open

andreubotella mentioned this pull request Sep 19, 2024

[css-overflow] Is continue: discard working in the fragment tree useful? #7708

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andreubotella added 3 commits October 4, 2024 08:40

[css-overflow-4] Draft spec for continue: collapse (#7708)

c2fa930

Clarification about float clearance in the automatic block size

c7df9c9

Update to only allow clamping after a line

1699d89

andreubotella force-pushed the continue-collapse branch from b3b73b4 to 1699d89 Compare October 3, 2024 23:40

andreubotella mentioned this pull request Oct 11, 2024

[css-overflow] Invisible line boxes and line-clamp #11021

Open

moz-wptsync-bot mentioned this pull request Oct 21, 2024

[Gecko Bug 1791226] Don't paint line-clamped lines. web-platform-tests/wpt#48729

Merged

frivoal requested changes Nov 4, 2024

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frivoal mentioned this pull request Nov 4, 2024

[css-overflow] Add spec text for the continue variant of line-clamp #10322

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[css-overflow-4] Draft spec for `continue: collapse` (#7708) #10816

[css-overflow-4] Draft spec for `continue: collapse` (#7708) #10816

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frivoal commented Nov 4, 2024

	must be pushed to that <a>fragmentation container</a>. If it is placed before a [=clamp point=],
	must be pushed to that <a>fragmentation container</a>.
	If it is placed before a [=clamp point=],

		If the value of 'max-lines' is not <dfn for=max-lines dfn-type=value>none</dfn>, then, where
		<var>N</var> is the computed value of 'max-lines':

		- A point immediately after a [=line box=] in the line-clamp container's [=block formatting
		context=].

		- The end of the line-clamp container, if there are any boxes after the last [=inline formatting
		context=] in the line-clamp container's [=block formatting context=].

[css-overflow-4] Draft spec for continue: collapse (#7708) #10816

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[css-overflow-4] Draft spec for continue: collapse (#7708) #10816

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frivoal commented Nov 4, 2024

[css-overflow-4] Draft spec for `continue: collapse` (#7708) #10816

[css-overflow-4] Draft spec for `continue: collapse` (#7708) #10816