[csswg-drafts] [css-grid-1] Clarify interaction of percentages and intrinsic sizing and the grid algorithm overall (#3418)

fantasai has just created a new issue for https://github.com/w3c/csswg-drafts:

== [css-grid-1] Clarify interaction of percentages and intrinsic sizing and the grid algorithm overall ==
In https://github.com/w3c/csswg-drafts/issues/1921#issuecomment-344442739 @fantasai wrote:

> To clarify, the spec is currently written in conformance with the above resolution (see https://drafts.csswg.org/css-grid-1/#valdef-grid-template-columns-length-percentage and https://drafts.csswg.org/css-grid-1/#intrinsic-sizes). But overall what's happening doesn't seem to be very clearly described.
> 
> Afaict, we could describe what is happening as the following (which is then implemented differently in UAs in order to optimize the number of passes):
> 
> 1. Size the Grid Container (per axis, for both axes)
>   - If it is definite, just get that size.
>   - If it is indefinite, run the grid sizing algorithm under min/max-content constraints, treating percentages as auto, in order to find the indefinite size.
> 2.  Size the Grid
>   - Run the grid sizing algorithm under normal constraints: auto behaves as auto, and percentages resolve against the size of the grid container as calculated in step #1.
> 
> Does this seem correct, or are there shortcuts under #1 that aren't reflected here?

In https://github.com/w3c/csswg-drafts/issues/1921#issuecomment-347993853 @mrego wrote:

> > Does this seem correct, or are there shortcuts under #1 that aren't reflected here?
> 
> Yes, probably that would be fine, despite Blink/WebKit implementation don't do that. So for us it'll imply an extra pass as described in #1 but probably that's just an implementation detail that shouldn't be considered in the spec.

Pulling this more editorial-level work out into this issue so I can close the main one.

Please view or discuss this issue at https://github.com/w3c/csswg-drafts/issues/3418 using your GitHub account

Received on Tuesday, 11 December 2018 00:21:04 UTC