[−]Trait piet_common::kurbo::Shape

pub trait Shape where
    <Self::BezPathIter as Iterator>::Item == PathEl, {
    type BezPathIter: Iterator;
    fn to_bez_path(&self, tolerance: f64) -> Self::BezPathIter;

    fn area(&self) -> f64;

    fn perimeter(&self, accuracy: f64) -> f64;

    fn winding(&self, pt: Point) -> i32;

    fn bounding_box(&self) -> Rect;

    fn into_bez_path(self, tolerance: f64) -> BezPath { ... }

    fn as_line(&self) -> Option<Line> { ... }

    fn as_rect(&self) -> Option<Rect> { ... }

    fn as_circle(&self) -> Option<Circle> { ... }

    fn as_path_slice(&self) -> Option<&[PathEl]> { ... }
}

A generic trait for open and closed shapes.

Associated Types

type BezPathIter: Iterator

The iterator resulting from to_bez_path.

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Required methods

fn to_bez_path(&self, tolerance: f64) -> Self::BezPathIter

Convert to a Bézier path, as an iterator over path elements.

Callers should exhaust the as_ methods first, as those are likely to be more efficient; in the general case, this allocates.

TODO: When GAT's land, the type of this can be changed to contain a &'a self reference, which would let us take iterators from complex shapes without cloning.

fn area(&self) -> f64

Signed area.

This method only produces meaningful results with closed shapes.

TODO: figure out sign convention, see #4.

fn perimeter(&self, accuracy: f64) -> f64

Total length of perimeter.

fn winding(&self, pt: Point) -> i32

Winding number of point.

This method only produces meaningful results with closed shapes.

TODO: figure out sign convention, see #4.

fn bounding_box(&self) -> Rect

The smallest rectangle that encloses the shape.

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Provided methods

fn into_bez_path(self, tolerance: f64) -> BezPath

fn as_line(&self) -> Option<Line>

If the shape is a line, make it available.

fn as_rect(&self) -> Option<Rect>

If the shape is a rectangle, make it available.

fn as_circle(&self) -> Option<Circle>

If the shape is a circle, make it available.

fn as_path_slice(&self) -> Option<&[PathEl]>

If the shape is stored as a slice of path elements, make that available.

Note: when GAT's land, a method like to_bez_path would be able to iterate through the slice with no extra allocation, without making any assumption that storage is contiguous.

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Implementations on Foreign Types

impl<'a, T> Shape for &'a T where
    T: Shape, 

Blanket implementation so impl Shape will accept owned or reference.

type BezPathIter = <T as Shape>::BezPathIter

impl<'a> Shape for &'a [PathEl]

type BezPathIter = Cloned<Iter<'a, PathEl>>

fn area(&self) -> f64

Signed area.

TODO: figure out sign convention, see #4.

fn winding(&self, pt: Point) -> i32

Winding number of point.

TODO: figure out sign convention, see #4.

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Implementors

impl Shape for BezPath

type BezPathIter = IntoIter<PathEl>

fn area(&self) -> f64

Signed area.

TODO: figure out sign convention, see #4.

fn winding(&self, pt: Point) -> i32

Winding number of point.

TODO: figure out sign convention, see #4.

impl Shape for Circle

type BezPathIter = CirclePathIter

impl Shape for Line

type BezPathIter = LinePathIter

fn area(&self) -> f64

Returning zero here is consistent with the contract (area is only meaningful for closed shapes), but an argument can be made that the contract should be tightened to include the Green's theorem contribution.

fn winding(&self, _pt: Point) -> i32

Same consideration as area.

impl Shape for Rect

type BezPathIter = RectPathIter

fn winding(&self, pt: Point) -> i32

Note: this function is carefully designed so that if the plane is tiled with rectangles, the winding number will be nonzero for exactly one of them.

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