[css3-flexbox] better algorithm for hypothetical main size

(separating from cross-size thread)

Hypothetical main size determination in flex layout algorithm [1] has
unnecessary assymetry wrt flex items parallel vs. orthogonal to main axis. The
distinction is not useful, because (1) items in parallel writing mode can have
orthogonal content and (2) there are other reasons for item layout to behave
similar to orthogonal writing mode, e.g. a multiline flexbox with orthogonal
main axis.

What matters is dependency of content max-size an min-size on cross size of
flex container.

The two bullet items on laying out items in available space should be replaced
with following:

<algorithm>
Otherwise, lay out the item using available space with following dimensions: 

* On main axis: 
    - if flex-basis is auto: infinite
    - if flex-basis 'fit-available' or 'fit-content':  
      flex-container's main size, constrained by its 
      min and max size.

* On cross axis:  flex container's cross size, constrained 
  by its min and max size.

The flex base size is the item's resulting measure.
</algorithm>

In Bugzilla: https://www.w3.org/Bugs/Public/show_bug.cgi?id=17475

Alex

Received on Tuesday, 12 June 2012 22:13:13 UTC