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Module Style.DimensionSource

CSS dimension values supporting length, percentage, auto, and calc().

A dimension represents a CSS size value used for properties like width, height, and flex_basis. Dimensions are stored in a compact tagged representation backed by Compact_length.

See Compact_length for conventions on percentage range, abstract units, and f32 precision.

A CSS dimension value.

Constructors

Sourceval length : float -> t

length value creates an absolute length dimension.

Sourceval percent : float -> t

percent value creates a percentage dimension.

The value is a fraction in the range 0.0, 1.0, where 0.5 represents 50%. For 0–100 percentage inputs, prefer pct.

Sourceval px : float -> t

px value creates an absolute length dimension in abstract pixel units.

Equivalent to length. Provided for CSS-style naming.

Sourceval pct : float -> t

pct percent creates a percentage dimension from a 0–100 value.

pct 50.0 is equivalent to percent 0.5.

Sourceval auto : t

auto represents automatic sizing.

Sourceval calc : int -> t

calc index creates a calc() dimension from an opaque index.

The index identifies a calc expression to be resolved later. The lower 3 bits are reserved as a tag and returned as 0.

Constants

Sourceval zero : t

zero is equivalent to length 0.0.

Inspection

Sourceval is_length : t -> bool

is_length t returns true if t is a length dimension.

Sourceval is_percent : t -> bool

is_percent t returns true if t is a percentage dimension.

Sourceval is_auto : t -> bool

is_auto t returns true if t is an auto dimension.

Sourceval is_calc : t -> bool

is_calc t returns true if t is a calc() dimension.

Sourceval is_zero : t -> bool

is_zero t returns true if t is a length with value 0.0.

Sourceval uses_percentage : t -> bool

uses_percentage t returns true if t involves percentage computation.

Returns true for percent and calc dimensions.

Value Extraction

Sourceval value : t -> float

value t extracts the numeric value from t.

Raises Failure if t is auto, min-content, max-content, or calc.

Sourceval to_option : t -> float option

to_option t returns Some value if t is a length, None otherwise.

Resolution

Sourceval resolved_percentage_size : t -> float -> float option

resolved_percentage_size t parent_size resolves percentage dimensions.

Returns Some (value * parent_size) if t is a percentage, None otherwise. The result is rounded to f32 precision to match Taffy behavior.

Sourceval resolved_percentage_size_with_calc : t -> float -> (int -> float -> float) -> float option

resolved_percentage_size_with_calc t parent_size calc_resolver resolves percentage and calc dimensions.

Returns:

  • Some (value * parent_size) if t is a percentage
  • Some (calc_resolver index parent_size) if t is a calc
  • None otherwise

The calc resolver receives the calc index and parent size, returning the computed value. Percentage results are rounded to f32 precision.

Sourceval maybe_resolve : t -> float option -> (int -> float -> float) -> float option

maybe_resolve t context calc_resolver resolves t using context.

Returns:

  • None if t is auto or context is None for percent/calc
  • Some value if t is a length
  • Some (context * value) if t is a percent and context is Some
  • Some (calc_resolver index context) if t is a calc and context is Some

Percentage and calc results are rounded to f32 precision.

Raises Failure if t is not length, percentage, auto, or calc.

Sourceval resolve_or_zero : t -> float option -> (int -> float -> float) -> float

resolve_or_zero t context calc_resolver resolves t or returns 0.0.

Equivalent to Option.value ~default:0.0 (maybe_resolve t context calc_resolver).

Comparison

Sourceval equal : t -> t -> bool

equal a b tests structural equality.

Calc dimensions are equal if their indices match. Lengths and percentages are compared within Float.epsilon tolerance.

Sourceval compare : t -> t -> int

compare a b provides total ordering.

Calc dimensions sort before others by index. Non-calc dimensions sort by tag then value.

Sourceval pp : Format.formatter -> t -> unit

pp fmt t formats t for debugging.

Sourceval to_string : t -> string

to_string t converts t to a human-readable string.

Examples: "10px", "50%", "auto", "calc(#0)".