Fixed

• Flexbox: don't apply cross-axis stretch alignment to children with auto margins (#861)

Support for named grid lines and grid areas

Taffy now supports named grid lines and areas.

As these rely on arbitrary user-provided strings, Taffy's Style struct is now generic
over a string-like type (via the CheapCloneStr trait). Additionally as the grid feature is optional,
it has a PhantomData field of that type to make type inference work.

Changed

• PrintTree and RoundTree: use Layout instead of &Layout (#849).
• Renamed TrackSizingFunction to GridTemplateComponent
• Renamed NonRepeatedTrackSizingFunction to TrackSizingFunction
• The Repeat variant of GridTemplateComponent now contains a new GridTemplateRepetition struct, which allows
  line names to be specifed in addition to tracks.
• The way that grid styles are exposed in the low-level API is now a lot more generic with many associated types.

Added

• GridTemplateArea struct and Style::grid_template_areas field
• Style::grid_template_column_names and Style::grid_template_row_names fields. If non-empty, these
  should have length of exactly one greater than the corresponding grid_template_column/grid_template_rows style.

Fixed

• Fix serde feature on 32bit targets (#845)

Fixed

• Fix: Calculate correct new grid size when expanding cell_occupancy_matrix in the negative direction (#843)

Added

• Impl GridItemStyle and BlockContainerStyle for Style (#832).

Highlights

The big feature in this release is support for calc() values in the low-level API.

To use this API:

• Implement the resolve_calc_value method when implementing the LayoutPartialTree trait.
• Pass a type-erased pointer (*const ()) to constructors like LengthPercentage::calc(...)

Taffy treats the pointer as an opaque value (excepting that it uses the low 3 bits as a tag) which it will
pass to LayoutPartialTree::resolve_calc_value along with a percentage resolution basis when it needs to
resolve the value.

Changed

• The representation of many "size" types is now a tagged pointer than an enum. This is to enable calc().
  The effected types are LengthPercentage, LengthPercentageAuto, Dimension, MinTrackSizingFunction, and
  MaxTrackSizingFunction types.

Added

• Special-case "compressible replaced elements" in grid sizing algorithm (#807)
  This allows for more correct sizing of "replaced" elements such as images that are children
  of flexbox or grid containers.

Fixed

• Grid: Fix infinite loop due to float precision in grid layout maximise tracks step (#792)
• Grid: Fix removed wrong addition, causing items to be misplaced. (#817)
• Grid: Fix grid placement for items with fixed primary axis (#818)
• Leaf layout: don't set available space to max-size (#819)

Fixed

• Add #[inline] annotation to some methods on TaffyTree (#802)
• Add TaffyTree::remove_children_range method (#802)

Fixed

• Fix infinite loop due to float precision in grid layout maximise tracks step (#792)

Fixed

• Grid: only stretch auto tracks if content-alignment is stretch (#783)

Fixed

• Fix detailed grid info for empty grid (#782)