Struct Point 

pub struct Point {
    pub x: i16,
    pub y: i16,
}

A point on the integer lattice.

i16 is the crate’s coordinate type for both input and output.

The coordinate cap

Coordinates are restricted to Point::MIN_COORD..=Point::MAX_COORD, i.e. -16384..=16383 — half of what i16 could hold. Polygon rejects anything outside it.

That one bit is what pays for everything else. It is exactly the bit that lets the crate compute the whole skeleton in i32 and f32, with no f64 and no i64 in the algorithm:

• The orientation determinant of three points needs 2 * d^2 where d is the largest coordinate difference. At the full i16 range that is 8_589_672_450 — it overflows i32 and reports the wrong side. Capped, it is 2_147_352_578, which fits i32 with 131_069 to spare, making every predicate exact. See crate::predicates.
• f32 resolves 0.002 at the cap, against 0.004 at the full range, which is what leaves the simulation enough room to work in.

Rounding

A straight skeleton’s interior nodes generally land on irrational coordinates even when every input vertex is an integer, so there is no lattice to compute on. The algorithm works internally in f32 and rounds only at the boundary, so a Node’s position is the nearest lattice point to its true location. When you need the unrounded value, every node also carries Node::exact.

Examples

use straight_skeleton::Point;

let p = Point::new(3, 4);
assert_eq!(p.x, 3);
assert_eq!(p.y, 4);

// Points convert from the obvious tuple and array forms.
assert_eq!(Point::from((3, 4)), p);
assert_eq!(Point::from([3, 4]), p);

Fields

x: i16

Horizontal coordinate.

y: i16

Vertical coordinate.

Implementations

impl Point

pub const ORIGIN: Point

The origin, (0, 0).

pub const MIN_COORD: i16 = -16384

The most negative coordinate a Polygon may use, -16384.

See Point for why the range is capped below what i16 could hold.

pub const MAX_COORD: i16 = 16383

The largest coordinate a Polygon may use, 16383.

See Point for why the range is capped below what i16 could hold.

pub const fn in_range(self) -> bool

Whether both coordinates are within MIN_COORD..=MAX_COORD.

Examples

use straight_skeleton::Point;

assert!(Point::new(16383, -16384).in_range());
assert!(!Point::new(16384, 0).in_range());
assert!(!Point::new(0, i16::MIN).in_range());

pub const fn new(x: i16, y: i16) -> Self

Constructs a point from its coordinates.

pub fn distance_squared(self, other: Point) -> u32

Squared distance to other, computed exactly in i32.

Exact for every in-range pair: the largest possible value is 2 * 32767^2 = 2_147_352_578, which fits comfortably.

Points outside the coordinate cap saturate rather than wrap, which keeps comparisons monotone; a Polygon cannot contain such a point anyway.

Examples

use straight_skeleton::Point;

assert_eq!(Point::new(0, 0).distance_squared(Point::new(3, 4)), 25);

impl Point

pub fn cast<T: NumCast>(self) -> Option<(T, T)>

Available on crate feature num-traits only.

Converts to any numeric type num-traits can cast to.

Always succeeds for the usual targets, since every i16 fits.

Examples

use straight_skeleton::Point;

let p = Point::new(3, -4);
assert_eq!(p.cast::<f32>(), Some((3.0, -4.0)));
assert_eq!(p.cast::<i64>(), Some((3, -4)));
// -4 has no unsigned representation.
assert_eq!(p.cast::<u8>(), None);

pub fn try_cast<T: ToPrimitive>(x: T, y: T) -> Option<Point>

Available on crate feature num-traits only.

Builds a point from any numeric type, if both coordinates land exactly on the i16 lattice.

Returns None rather than rounding. Note this is stricter than num_traits’ own to_i16, which truncates 0.5 to 0; a silently moved vertex is the last thing a geometry crate should hand you.

Examples

use straight_skeleton::Point;

assert_eq!(Point::try_cast(3.0f64, -4.0f64), Some(Point::new(3, -4)));
assert_eq!(Point::try_cast(1e9f64, 0.0f64), None);   // out of range
assert_eq!(Point::try_cast(0.5f64, 0.0f64), None);   // off the lattice
assert_eq!(Point::try_cast(3i64, -4i64), Some(Point::new(3, -4)));

Trait Implementations

impl Clone for Point

fn clone(&self) -> Point

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Copy for Point

impl Debug for Point

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

Formats the value using the given formatter.

impl Default for Point

fn default() -> Point

Returns the “default value” for a type.

impl<'de> Deserialize<'de> for Point

fn deserialize<__D>(__deserializer: __D) -> Result<Self, __D::Error>

where __D: Deserializer<'de>,

Deserialize this value from the given Serde deserializer.

impl Eq for Point

impl From<(i16, i16)> for Point

fn from((x, y): (i16, i16)) -> Self

Converts to this type from the input type.

impl From<Coord<i16>> for Point

Available on crate feature geo-types only.

fn from(c: Coord<i16>) -> Self

Converts to this type from the input type.

impl From<I16Vec2> for Point

Available on crate feature glam only.

fn from(v: I16Vec2) -> Self

Converts to this type from the input type.

impl From<Point2<i16>> for Point

Available on crate feature mint only.

fn from(p: Point2<i16>) -> Self

Converts to this type from the input type.

impl From<Point<i16>> for Point

Available on crate feature geo-types only.

fn from(p: Point<i16>) -> Self

Converts to this type from the input type.

impl From<Point> for (i16, i16)

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for [i16; 2]

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for Coord<i16>

Available on crate feature geo-types only.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for Point<i16>

Available on crate feature geo-types only.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for Coord<f64>

Available on crate feature geo-types only.

Widening to f64 is exact, which is what makes this From rather than TryFrom: f64 has 53 mantissa bits and i16 needs 16.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for I16Vec2

Available on crate feature glam only.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for IVec2

Available on crate feature glam only.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for Vec2

Available on crate feature glam only.

i16 -> f32 is exact: 16 bits fits comfortably in a 24-bit mantissa.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for Point2<i16>

Available on crate feature mint only.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for Vector2<i16>

Available on crate feature mint only.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Point> for Point2<f32>

Available on crate feature mint only.

fn from(p: Point) -> Self

Converts to this type from the input type.

impl From<Vector2<i16>> for Point

Available on crate feature mint only.

fn from(v: Vector2<i16>) -> Self

Converts to this type from the input type.

impl From<[i16; 2]> for Point

fn from([x, y]: [i16; 2]) -> Self

Converts to this type from the input type.

impl Hash for Point

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 Ord for Point

fn cmp(&self, other: &Point) -> Ordering

This method returns an Ordering between self and other.

fn max(self, other: Self) -> Self

where Self: Sized,

Compares and returns the maximum of two values.

fn min(self, other: Self) -> Self

where Self: Sized,

Compares and returns the minimum of two values.

fn clamp(self, min: Self, max: Self) -> Self

where Self: Sized,

Restrict a value to a certain interval.

impl PartialEq for Point

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

Equality operator ==.

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

Inequality operator !=.

impl PartialOrd for Point

fn partial_cmp(&self, other: &Point) -> Option<Ordering>

This method returns an ordering between self and other values if one exists.

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

Tests less than (for self and other) and is used by the < operator.

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

Tests less than or equal to (for self and other) and is used by the <= operator.

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

Tests greater than (for self and other) and is used by the > operator.

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

Tests greater than or equal to (for self and other) and is used by the >= operator.

impl Serialize for Point

fn serialize<__S>(&self, __serializer: __S) -> Result<__S::Ok, __S::Error>

where __S: Serializer,

Serialize this value into the given Serde serializer.

impl StructuralPartialEq for Point

impl TryFrom<Coord> for Point

Available on crate feature geo-types only.

type Error = CoordError

The type returned in the event of a conversion error.

fn try_from(c: Coord<f64>) -> Result<Self, CoordError>

Performs the conversion.

impl TryFrom<IVec2> for Point

Available on crate feature glam only.

type Error = CoordError

The type returned in the event of a conversion error.

fn try_from(v: IVec2) -> Result<Self, CoordError>

Performs the conversion.

impl TryFrom<Point2<f32>> for Point

Available on crate feature mint only.

type Error = CoordError

The type returned in the event of a conversion error.

fn try_from(p: Point2<f32>) -> Result<Self, CoordError>

Performs the conversion.

impl TryFrom<Vec2> for Point

Available on crate feature glam only.

type Error = CoordError

The type returned in the event of a conversion error.

fn try_from(v: Vec2) -> Result<Self, CoordError>

Performs the conversion.