Bug 150674 – [css-grid] Fix fr tracks sizing under min|max-size constraints

• Component: CSS
• Status: RESOLVED FIXED

[Sergio Villar Senin]

Specs say:

"When the grid container is being sized under a min-content constraint, a track with a flexible min track sizing function is treated as if its min track sizing function was min-content for the purposes of this step"

We are not doing it, so in the end we're sizing them as any other fr track. This means that the size of the track will be used the max-content of the items inside the track instead of the min-content.

For more info: https://lists.w3.org/Archives/Public/www-style/2015May/0116.html

[Sergio Villar Senin]

The text mentioned in comment #1 is no longer included in the specs. However there is a new paragraph now which says:

"If using this flex fraction would cause the grid to be smaller than the grid container’s min-width/height (or larger than the grid container’s max-width/height), then redo this step, treating the free space as definite and the available grid space as equal to the grid container’s content box size when it’s sized to its min-width/height (max-width/height)."

[Sergio Villar Senin]

Created attachment 294159 [details]
Patch

[Darin Adler]

Comment on attachment 294159 [details]
Patch

View in context: https://bugs.webkit.org/attachment.cgi?id=294159&action=review

> Source/WebCore/rendering/RenderGrid.cpp:805
> +    computeFlexSizedTracksGrowth(direction, sizingData.sizingOperation, tracks, flexibleSizedTracksIndex, flexFraction, increments, totalGrowth);

We should consider making this function have return values instead of out arguments in the future.

> Source/WebCore/rendering/RenderGrid.cpp:812
> +        auto minSize = computeContentLogicalHeight(MinSize, style().logicalMinHeight(), LayoutUnit(-1));
> +        auto maxSize = computeContentLogicalHeight(MaxSize, style().logicalMaxHeight(), LayoutUnit(-1));

The use of -1 as a magic value here and elsewhere is quite ugly.

[Sergio Villar Senin]

Committed r208531: <http://trac.webkit.org/changeset/208531>