[css-grid] Stretching Fixed-size Tracks

[fantasai]

So I was just adding more examples to the Grid spec, and I think we should revisit the decision of which tracks 'align/justify-content: stretch' applies to. Currently it only applies to auto-sized (i.e. content-sized) tracks. However, I do expect something like

  grid-template-columns: repeat(auto-fill, 5em);
  justify-content: [whatever]

to be a common use case, and the fact that all the alignment values except stretch have their intended effect, and can be easily switched among, seems odd.

In contrast, I expect wanting content-sized items to be stretched while fixed-size tracks in the same grid are not, to be a less common case. In any case, thoughts on this point?

[mrego]

Just a quick thought, if we decide to stretch fixed-size tracks, as stretch is the default value for justify-content, a very simple grid example will stretch horizontally to take whole viewport (dunno if we want that to be the default behavior).

So this example:

  <div style="display: grid; grid-template-columns: 100px 100px;">
    <div style="background: magenta;">item 1</div>
    <div style="background: cyan;">item 2</div>
  </div>

Would be the same than using grid-template-columns: 1fr 1fr;.
Dunno if that's what we want by default in all the grids, but IMHO the first time you use them you might be quite confused.

[rachelandrew]

That sounds very confusing. I'd expect 100 pixel tracks not to stretch as a default behaviour.

[fantasai]

The default value for align/justify-self has to be stretch, but for align/justify-content we could easily make it start -- the real default is 'normal'.

[tabatkins]

Yeah, I'm very confused about this too. stretch very explicitly doesn't stretch things with a definite size in Flexbox already; why would you expect it to stretch definite-size things in Grid?

Like, all the other values work because they're not trying to change the size of the tracks, just their positions. Only stretch does that.