[css-grid-1] Interpolating track listings · Issue #3201 · w3c/csswg-drafts (original) (raw)

Currently grid-template-rows/columns interpolate “per computed value”, which means that if the number of tracks differs, or any track changes to/from a particular keyword value to any other value, or if a line name is added/removed at any position, the entire track listing is interpolated as “discrete”. But we have some more granular options:

• Check interpolation type per track, rather than for the entire list, before falling back to discrete. I.e. a length-percentage track can animate between two values while an adjacent auto track flips discretely to min-content.
• Allow discrete interpolation of line name changes independently of track sizes.
• Allow interpolation of mismatched track list lengths, by filling in missing values from grid-auto-rows/columns.

Wanted to hear back from implementers what they think is reasonable here. CC @MatsPalmgren @mrego @javifernandez @birtles