397 lines
11 KiB
Rust
397 lines
11 KiB
Rust
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// pathfinder/geometry/src/outline.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 compressed in-memory representation of paths.
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use crate::point::Point2DF32;
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use crate::segment::{Segment, SegmentFlags, SegmentKind};
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use euclid::{Point2D, Rect};
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use lyon_path::PathEvent;
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use std::fmt::{self, Debug, Formatter};
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use std::mem;
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#[derive(Debug)]
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pub struct Outline {
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pub contours: Vec<Contour>,
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bounds: Rect<f32>,
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}
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pub struct Contour {
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points: Vec<Point2DF32>,
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flags: Vec<PointFlags>,
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}
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bitflags! {
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pub struct PointFlags: u8 {
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const CONTROL_POINT_0 = 0x01;
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const CONTROL_POINT_1 = 0x02;
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}
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}
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impl Outline {
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#[inline]
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pub fn new() -> Outline {
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Outline {
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contours: vec![],
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bounds: Rect::zero(),
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}
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}
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#[inline]
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pub fn from_segments<I>(segments: I) -> Outline
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where
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I: Iterator<Item = Segment>,
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{
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let mut outline = Outline::new();
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let mut current_contour = Contour::new();
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let mut bounding_points = None;
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for segment in segments {
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if segment.flags.contains(SegmentFlags::FIRST_IN_SUBPATH) {
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if !current_contour.is_empty() {
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outline
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.contours
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.push(mem::replace(&mut current_contour, Contour::new()));
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}
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current_contour.push_point(
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segment.baseline.from(),
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PointFlags::empty(),
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&mut bounding_points,
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);
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}
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if segment.flags.contains(SegmentFlags::CLOSES_SUBPATH) {
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if !current_contour.is_empty() {
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outline
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.contours
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.push(mem::replace(&mut current_contour, Contour::new()));
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}
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continue;
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}
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if segment.is_none() {
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continue;
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}
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if !segment.is_line() {
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current_contour.push_point(
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segment.ctrl.from(),
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PointFlags::CONTROL_POINT_0,
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&mut bounding_points,
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);
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if !segment.is_quadratic() {
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current_contour.push_point(
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segment.ctrl.to(),
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PointFlags::CONTROL_POINT_1,
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&mut bounding_points,
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);
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}
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}
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current_contour.push_point(
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segment.baseline.to(),
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PointFlags::empty(),
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&mut bounding_points,
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);
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}
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if !current_contour.is_empty() {
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outline.contours.push(current_contour)
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}
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if let Some((upper_left, lower_right)) = bounding_points {
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outline.bounds =
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Rect::from_points([upper_left.as_euclid(), lower_right.as_euclid()].iter())
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}
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outline
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}
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#[inline]
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pub fn bounds(&self) -> &Rect<f32> {
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&self.bounds
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}
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}
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impl Contour {
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#[inline]
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pub fn new() -> Contour {
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Contour {
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points: vec![],
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flags: vec![],
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}
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}
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#[inline]
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pub fn iter(&self) -> ContourIter {
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ContourIter {
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contour: self,
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index: 0,
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}
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}
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#[inline]
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pub fn is_empty(&self) -> bool {
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self.points.is_empty()
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}
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#[inline]
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pub fn len(&self) -> u32 {
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self.points.len() as u32
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}
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#[inline]
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pub fn position_of(&self, index: u32) -> Point2DF32 {
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self.points[index as usize]
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}
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// TODO(pcwalton): Pack both min and max into a single SIMD register?
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#[inline]
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fn push_point(
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&mut self,
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point: Point2DF32,
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flags: PointFlags,
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bounding_points: &mut Option<(Point2DF32, Point2DF32)>,
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) {
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self.points.push(point);
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self.flags.push(flags);
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match *bounding_points {
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Some((ref mut upper_left, ref mut lower_right)) => {
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*upper_left = upper_left.min(point);
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*lower_right = lower_right.max(point);
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}
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None => *bounding_points = Some((point, point)),
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}
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}
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#[inline]
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pub fn segment_after(&self, point_index: u32) -> Segment {
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debug_assert!(self.point_is_endpoint(point_index));
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let mut segment = Segment::none();
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segment.baseline.set_from(&self.position_of(point_index));
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let point1_index = self.add_to_point_index(point_index, 1);
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if self.point_is_endpoint(point1_index) {
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segment.baseline.set_to(&self.position_of(point1_index));
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segment.kind = SegmentKind::Line;
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} else {
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segment.ctrl.set_from(&self.position_of(point1_index));
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let point2_index = self.add_to_point_index(point_index, 2);
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if self.point_is_endpoint(point2_index) {
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segment.baseline.set_to(&self.position_of(point2_index));
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segment.kind = SegmentKind::Quadratic;
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} else {
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segment.ctrl.set_to(&self.position_of(point2_index));
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segment.kind = SegmentKind::Cubic;
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let point3_index = self.add_to_point_index(point_index, 3);
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segment.baseline.set_to(&self.position_of(point3_index));
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}
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}
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segment
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}
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#[inline]
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pub fn point_is_endpoint(&self, point_index: u32) -> bool {
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!self.flags[point_index as usize]
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.intersects(PointFlags::CONTROL_POINT_0 | PointFlags::CONTROL_POINT_1)
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}
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#[inline]
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pub fn add_to_point_index(&self, point_index: u32, addend: u32) -> u32 {
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let (index, limit) = (point_index + addend, self.len());
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if index >= limit {
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index - limit
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} else {
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index
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}
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}
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#[inline]
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pub fn point_is_logically_above(&self, a: u32, b: u32) -> bool {
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let (a_y, b_y) = (self.points[a as usize].y(), self.points[b as usize].y());
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a_y < b_y || (a_y == b_y && a < b)
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}
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#[inline]
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pub fn prev_endpoint_index_of(&self, mut point_index: u32) -> u32 {
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loop {
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point_index = self.prev_point_index_of(point_index);
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if self.point_is_endpoint(point_index) {
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return point_index;
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}
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}
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}
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#[inline]
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pub fn next_endpoint_index_of(&self, mut point_index: u32) -> u32 {
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loop {
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point_index = self.next_point_index_of(point_index);
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if self.point_is_endpoint(point_index) {
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return point_index;
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}
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}
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}
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#[inline]
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pub fn prev_point_index_of(&self, point_index: u32) -> u32 {
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if point_index == 0 {
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self.len() - 1
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} else {
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point_index - 1
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}
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}
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#[inline]
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pub fn next_point_index_of(&self, point_index: u32) -> u32 {
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if point_index == self.len() - 1 {
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0
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} else {
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point_index + 1
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}
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}
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}
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impl Debug for Contour {
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#[inline]
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fn fmt(&self, formatter: &mut Formatter) -> fmt::Result {
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formatter.write_str("[")?;
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if formatter.alternate() {
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formatter.write_str("\n")?
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}
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for (index, segment) in self.iter().enumerate() {
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if index > 0 {
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formatter.write_str(" ")?;
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}
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if formatter.alternate() {
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formatter.write_str("\n ")?;
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}
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write_path_event(formatter, &segment)?;
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}
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if formatter.alternate() {
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formatter.write_str("\n")?
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}
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formatter.write_str("]")?;
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return Ok(());
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fn write_path_event(formatter: &mut Formatter, path_event: &PathEvent) -> fmt::Result {
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match *path_event {
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PathEvent::Arc(..) => {
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// TODO(pcwalton)
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formatter.write_str("TODO: arcs")?;
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}
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PathEvent::Close => formatter.write_str("z")?,
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PathEvent::MoveTo(to) => {
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formatter.write_str("M")?;
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write_point(formatter, to)?;
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}
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PathEvent::LineTo(to) => {
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formatter.write_str("L")?;
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write_point(formatter, to)?;
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}
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PathEvent::QuadraticTo(ctrl, to) => {
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formatter.write_str("Q")?;
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write_point(formatter, ctrl)?;
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write_point(formatter, to)?;
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}
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PathEvent::CubicTo(ctrl0, ctrl1, to) => {
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formatter.write_str("C")?;
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write_point(formatter, ctrl0)?;
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write_point(formatter, ctrl1)?;
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write_point(formatter, to)?;
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}
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}
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Ok(())
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}
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fn write_point(formatter: &mut Formatter, point: Point2D<f32>) -> fmt::Result {
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write!(formatter, " {},{}", point.x, point.y)
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}
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}
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}
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#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, PartialOrd, Ord)]
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pub struct PointIndex(u32);
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impl PointIndex {
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#[inline]
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pub fn new(contour: u32, point: u32) -> PointIndex {
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debug_assert!(contour <= 0xfff);
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debug_assert!(point <= 0x000f_ffff);
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PointIndex((contour << 20) | point)
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}
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#[inline]
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pub fn contour(self) -> u32 {
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self.0 >> 20
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}
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#[inline]
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pub fn point(self) -> u32 {
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self.0 & 0x000f_ffff
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}
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}
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pub struct ContourIter<'a> {
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contour: &'a Contour,
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index: u32,
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}
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impl<'a> Iterator for ContourIter<'a> {
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type Item = PathEvent;
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#[inline]
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fn next(&mut self) -> Option<PathEvent> {
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let contour = self.contour;
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if self.index == contour.len() + 1 {
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return None;
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}
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if self.index == contour.len() {
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self.index += 1;
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return Some(PathEvent::Close);
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}
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let point0_index = self.index;
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let point0 = contour.position_of(point0_index);
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self.index += 1;
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if point0_index == 0 {
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return Some(PathEvent::MoveTo(point0.as_euclid()));
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}
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if contour.point_is_endpoint(point0_index) {
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return Some(PathEvent::LineTo(point0.as_euclid()));
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}
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let point1_index = self.index;
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let point1 = contour.position_of(point1_index);
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self.index += 1;
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if contour.point_is_endpoint(point1_index) {
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return Some(PathEvent::QuadraticTo(
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point0.as_euclid(),
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point1.as_euclid(),
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));
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}
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let point2_index = self.index;
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let point2 = contour.position_of(point2_index);
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self.index += 1;
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debug_assert!(contour.point_is_endpoint(point2_index));
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Some(PathEvent::CubicTo(
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point0.as_euclid(),
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point1.as_euclid(),
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point2.as_euclid(),
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))
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}
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}
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