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Trait Curve

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pub trait Curve: Into<Segment> {

Show 17 methods    // Required methods
    fn flatness(&self) -> Scalar;
    fn transform(&self, tr: Transform) -> Self;
    fn start(&self) -> Point;
    fn end(&self) -> Point;
    fn at(&self, t: Scalar) -> Point;
    fn split_at(&self, t: Scalar) -> (Self, Self);
    fn cut(&self, a: Scalar, b: Scalar) -> Self;
    fn bbox(&self, init: Option<BBox>) -> BBox;
    fn offset(&self, dist: Scalar, out: &mut impl Extend<Segment>);
    fn deriv(&self) -> Segment;
    fn reverse(&self) -> Self;
    fn roots(&self) -> CurveRoots;
    fn extremities(&self) -> CurveExtremities;
    fn length(&self, t0: Scalar, t1: Scalar) -> Scalar;

    // Provided methods
    fn flatten(&self, tr: Transform, flatness: Scalar) -> CurveFlattenIter ⓘ { ... }
    fn split(&self) -> (Self, Self) { ... }
    fn param_at_length(&self, l: Scalar, error: Option<Scalar>) -> Scalar { ... }

}
Expand description

Set of operations common to all bezier curves.

Required Methods§

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fn flatness(&self) -> Scalar

Correspond to maximum deviation of the curve from the straight line f = max |curve(t) - line(curve_start, curve_end)(t)|. This function actually returns 16.0 * f^2 to avoid unneeded division and square root.

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fn transform(&self, tr: Transform) -> Self

Apply affine transformation to the curve

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fn start(&self) -> Point

Point at which curve starts

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fn end(&self) -> Point

Point at which curve ends

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fn at(&self, t: Scalar) -> Point

Evaluate curve at parameter value t in (0.0..=1.0)

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fn split_at(&self, t: Scalar) -> (Self, Self)

Split the curve at parameter value t

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fn cut(&self, a: Scalar, b: Scalar) -> Self

Create sub-curve specified starting at parameter value a and ending at value b

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fn bbox(&self, init: Option<BBox>) -> BBox

Extend provided init bounding box with the bounding box of the curve

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fn offset(&self, dist: Scalar, out: &mut impl Extend<Segment>)

Offset the curve by distance dist, result is inserted into out container

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fn deriv(&self) -> Segment

Derivative with respect to t, deriv(t) = [curve'(t)_x, curve'(t)_y]

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fn reverse(&self) -> Self

Identical curve but directed from end to start, instead of start to end.

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fn roots(&self) -> CurveRoots

Find roots of the equation curve(t)_y = 0. Values of the parameter at which curve crosses y axis.

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fn extremities(&self) -> CurveExtremities

Find all extremities of the curve curve'(t)_x = 0 || curve'(t)_y = 0

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fn length(&self, t0: Scalar, t1: Scalar) -> Scalar

Calculate length of the curve from t0 to t1

Provided Methods§

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fn flatten(&self, tr: Transform, flatness: Scalar) -> CurveFlattenIter ⓘ

Convert curve to an iterator over line segments with desired flatness

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fn split(&self) -> (Self, Self)

Optimized version of Curve::split_at(0.5)

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fn param_at_length(&self, l: Scalar, error: Option<Scalar>) -> Scalar

Find value of parameter t given desired l length of the segment

This method is not particularly fast, parameter value is found by solving f(t) = self.length(0.0, t) - l == 0 using Newton’s method with fallback to bisection if next iteration will produce out of bound value.

Reference: https://www.geometrictools.com/Documentation/MovingAlongCurveSpecifiedSpeed.pdf

Dyn Compatibility§

This trait is not dyn compatible.

In older versions of Rust, dyn compatibility was called "object safety", so this trait is not object safe.

Implementors§