Remove the `cubic_to_quadratic` module, as it's unneeded now
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Patrick Walton
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fb692acf05
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@ -1,137 +0,0 @@
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// pathfinder/geometry/src/cubic_to_quadratic.rs
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//
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// Copyright © 2019 The Pathfinder Project Developers.
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//
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// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
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// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
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// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
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// option. This file may not be copied, modified, or distributed
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// except according to those terms.
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//! A version of Lyon's `cubic_to_quadratic` that is less sensitive to floating point error.
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use euclid::Point2D;
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use lyon_geom::{CubicBezierSegment, QuadraticBezierSegment};
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use lyon_path::PathEvent;
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const MAX_APPROXIMATION_ITERATIONS: u8 = 32;
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/// Approximates a single cubic Bézier curve with a series of quadratic Bézier curves.
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pub struct CubicToQuadraticSegmentIter {
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cubic_curves: Vec<CubicBezierSegment<f32>>,
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error_bound: f32,
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iteration: u8,
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}
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impl CubicToQuadraticSegmentIter {
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pub fn new(cubic: &CubicBezierSegment<f32>, error_bound: f32) -> CubicToQuadraticSegmentIter {
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let (curve_a, curve_b) = cubic.split(0.5);
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CubicToQuadraticSegmentIter {
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cubic_curves: vec![curve_b, curve_a],
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error_bound: error_bound,
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iteration: 0,
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}
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}
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}
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impl Iterator for CubicToQuadraticSegmentIter {
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type Item = QuadraticBezierSegment<f32>;
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fn next(&mut self) -> Option<QuadraticBezierSegment<f32>> {
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let mut cubic = match self.cubic_curves.pop() {
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Some(cubic) => cubic,
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None => return None,
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};
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while self.iteration < MAX_APPROXIMATION_ITERATIONS {
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self.iteration += 1;
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// See Sederberg § 2.6, "Distance Between Two Bézier Curves".
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let delta_ctrl_0 = (cubic.from - cubic.ctrl1 * 3.0) + (cubic.ctrl2 * 3.0 - cubic.to);
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let delta_ctrl_1 = (cubic.ctrl1 * 3.0 - cubic.from) + (cubic.to - cubic.ctrl2 * 3.0);
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let max_error = f32::max(delta_ctrl_1.length(), delta_ctrl_0.length()) / 6.0;
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if max_error < self.error_bound {
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break
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}
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let (cubic_a, cubic_b) = cubic.split(0.5);
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self.cubic_curves.push(cubic_b);
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cubic = cubic_a
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}
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let approx_ctrl_0 = (cubic.ctrl1 * 3.0 - cubic.from) * 0.5;
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let approx_ctrl_1 = (cubic.ctrl2 * 3.0 - cubic.to) * 0.5;
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Some(QuadraticBezierSegment {
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from: cubic.from,
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ctrl: approx_ctrl_0.lerp(approx_ctrl_1, 0.5).to_point(),
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to: cubic.to,
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})
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}
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}
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pub struct CubicToQuadraticTransformer<I> where I: Iterator<Item = PathEvent> {
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inner: I,
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segment_iter: Option<CubicToQuadraticSegmentIter>,
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last_point: Point2D<f32>,
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error_bound: f32,
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}
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impl<I> CubicToQuadraticTransformer<I> where I: Iterator<Item = PathEvent> {
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#[inline]
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pub fn new(inner: I, error_bound: f32) -> CubicToQuadraticTransformer<I> {
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CubicToQuadraticTransformer {
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inner: inner,
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segment_iter: None,
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last_point: Point2D::zero(),
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error_bound: error_bound,
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}
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}
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}
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impl<I> Iterator for CubicToQuadraticTransformer<I> where I: Iterator<Item = PathEvent> {
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type Item = PathEvent;
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fn next(&mut self) -> Option<PathEvent> {
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if let Some(ref mut segment_iter) = self.segment_iter {
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if let Some(quadratic) = segment_iter.next() {
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return Some(PathEvent::QuadraticTo(quadratic.ctrl, quadratic.to))
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}
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}
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self.segment_iter = None;
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match self.inner.next() {
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None => None,
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Some(PathEvent::CubicTo(ctrl1, ctrl2, to)) => {
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let cubic = CubicBezierSegment {
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from: self.last_point,
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ctrl1: ctrl1,
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ctrl2: ctrl2,
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to: to,
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};
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self.last_point = to;
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self.segment_iter = Some(CubicToQuadraticSegmentIter::new(&cubic,
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self.error_bound));
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self.next()
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}
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Some(PathEvent::MoveTo(to)) => {
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self.last_point = to;
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Some(PathEvent::MoveTo(to))
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}
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Some(PathEvent::LineTo(to)) => {
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self.last_point = to;
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Some(PathEvent::LineTo(to))
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}
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Some(PathEvent::QuadraticTo(ctrl, to)) => {
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self.last_point = to;
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Some(PathEvent::QuadraticTo(ctrl, to))
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}
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Some(PathEvent::Close) => Some(PathEvent::Close),
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Some(PathEvent::Arc(to, vector, angle_from, angle_to)) => {
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self.last_point = to;
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Some(PathEvent::Arc(to, vector, angle_from, angle_to))
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}
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}
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}
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}
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@ -17,7 +17,6 @@ extern crate bitflags;
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pub mod basic;
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pub mod clip;
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pub mod cubic_to_quadratic;
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pub mod monotonic;
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pub mod normals;
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pub mod orientation;
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