1315750 - [css-grid] Baseline Self-Alignment must be applied only to items in the same baseline sharing group.

Status: UNCONFIRMED

(Core :: Layout: Grid, defect, P3)

Description

[Javier Fernandez]

Attachment: baseline-groups-bug.html

User Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Firefox/45.0
Build ID: 20160921025640

Steps to reproduce:

1- load the attached case


Actual results:

The four items in each grid are self-baseline aligned together, without taking their baseline sharing group into account (result.png).


Expected results:

Each grid should align the four items in 2 groups, using their respective baseline sharing groups (expected.png).

Comment 1

[Javier Fernandez]

Attachment: baseline-group-bug-result.png

Comment 2

[Javier Fernandez]

Attachment: baseline-group-bug-expected.png

Comment 3

[Javier Fernandez]

The section 6.3 Baseline Self-Alignment of the CSS Box Alignment specification states the following:

https://drafts.csswg.org/css-align/#baseline-align-self
"Boxes participating in row-like layout contexts (shared alignment contexts) can be baseline-aligned to each other. This effectively increases the margins on the box to align its alignment baseline with other baseline-aligned boxes in its group."

The section 8.2 Baseline Alignment Terminology states the following:

https://drafts.csswg.org/css-align/#baseline-sharing-group
A baseline-sharing group is composed of boxes that participate in baseline alignment together. This is possible only if they

* share an alignment context whose axis is parallel to their inline axis
* either have the same block flow direction and baseline alignment preference, or have opposite block flow direction and opposite baseline alignment preference (in other words, the baselines that want to align are on the same side of the alignment context).