[css-grid] step zero in 10.5

The recently added step zero in "10.5. Grid Item Placement Algorithm"
says:
"This effectively changes the order of their boxes in the box-tree,
and how the rest of this algorithm deals with the generated flex items."
https://drafts.csswg.org/css-grid/#auto-placement-algo

I suppose you mean "grid items"?  I don't understand what the latter
part about "generated grid items" is trying to say though.
Please clarify.

Also, why do you elaborate here about how to do the ordering at all?
Couldn't you simply say that this algorithm works on boxes in
"order-modified document order"? a term used elsewhere in Grid
and linked to its definition in Flexbox:
https://drafts.csswg.org/css-flexbox-1/#order-modified-document-order

I would much prefer if you use already established terms and
definitions to avoid ambiguity (i.e. is the added text here in fact
the same as the "order-modified document order" or is there some
subtle difference?)

There is also this (new) note:
"Note: Absolutely-positioned children of a grid container do not
participate in grid layout, but are reordered together with any grid
item children."

I think it's a mistake to mention abs.pos. boxes here.  This algorithm
doesn't apply to abs.pos. boxes at all.   Chapter  "11.2. With a Grid
Container as Parent" already covers this and it's clear:
"An absolutely-positioned child of a grid container does not affect
the placement of other items or the sizing of the grid. However, it
does participate in the reordering step (see order), which has an
effect on painting order."
https://drafts.csswg.org/css-grid/#static-position

I think the added "reordered together with any grid item children"
part adds confusion because it suggests that grid items are affected
by abs.pos. box order somehow (or vice versa) which isn't the case.
These two types of boxes can be sorted orthogonally.

So I suggest you remove the note about abs.pos. boxes in step zero,
or at least remove the part after the comma.  Also, remove the added
"(and any absolutely-positioned grid container children)".
Step zero should simply say "sort grid item boxes in 'order-modified
document order'" with a link to the definition of that term.
Alternatively, remove step zero and add "this algorithm works on
grid item boxes in 'order-modified document order'" in the intro.

Thanks,
Mats

Received on Sunday, 28 February 2016 22:33:29 UTC