Struct Ratio 

pub struct Ratio {
    pub numerator: u16,
    pub denominator: u16,
}

A fraction of the base unit.

Rational rather than floating point so the scale is exact, comparable and usable in a const. At the default base every ratio below divides evenly.

Fields

numerator: u16

Top of the fraction.

denominator: u16

Bottom of the fraction. Never zero for any ratio this crate defines.

Implementations

impl Ratio

pub const fn px_at(self, base_px: u16) -> u16

Resolve against a base measured in whole pixels, rounding to nearest.

Integer maths throughout, and exact for every Step at DEFAULT_BASE_PX because the scale is eighths. This is Self::quanta with a quantum of one pixel, kept separate only so the common case stays const.

pub fn scale(self, base: f32) -> f32

Resolve against an arbitrary base, keeping the fraction.

The exact value, before any surface gets a say. Prefer Surface::resolve unless you specifically want the unsnapped number.

pub fn quanta(self, base: f32, quantum: f32) -> u32

How many whole quanta this ratio is worth on a surface whose smallest representable step is quantum.

The generalisation of “round to a pixel”. A display quantises to one pixel and the answer is usually uninteresting; a terminal quantises to one cell and the answer is the whole design. Rounds to nearest, and does not floor at one: a gap that lands below half a quantum should collapse to nothing, because on that surface it is nothing.

A quantum that is zero, negative or not finite yields 0 rather than panicking or returning infinity — a surface with no smallest step is a caller error, not a layout to guess at.

pub fn quantize(self, base: f32, quantum: f32) -> f32

Resolve against a base and snap to a whole number of quantum.

The value Self::quanta counts, back in the surface’s own units. Guards the degenerate quantum in its own right rather than leaning on Self::quanta: a count of zero times a non-finite quantum is NaN, not zero.

pub fn css(self) -> String

The CSS value, as an expression over BASE_TOKEN.

A whole multiple of the base emits without a division, and 1:1 emits the bare var(), because calc(var(--geometry-base) * 1 / 1) is noise.

Trait Implementations

impl Clone for Ratio

fn clone(&self) -> Ratio

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for Ratio

impl Debug for Ratio

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for Ratio

impl Hash for Ratio

fn hash<__H: Hasher>(&self, state: &mut __H)

Feeds this value into the given Hasher.

fn hash_slice<H>(data: &[Self], state: &mut H)

where H: Hasher, Self: Sized,

Feeds a slice of this type into the given Hasher.

impl PartialEq for Ratio

fn eq(&self, other: &Ratio) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for Ratio