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dotCooCoo
bc19dd64db
`rdp` measured each sample to the infinite line through the ends of the line that would replace it. A sample beyond either end could be far from that line segment and still be dropped: a line to (100, 0), a 0.2 pt U-turn and a line back to (50, 0.2) became one line at a tolerance of 1 pt, leaving the tip 50 pt away. `rdp` now measures to the segment, so a sample beyond an end is measured to that end, and a zero-length chord measures to its point as before. The test `a_path_that_turns_back_past_its_end_converted_to_straight_lines_keeps_its_tip` covers that path.
1106 lines
48 KiB
Rust
1106 lines
48 KiB
Rust
//! Object → Path commands: Simplify, Smooth, Remove redundant points, Add Anchor Points, Average,
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//! Join, Split Into Grid.
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use std::collections::{BTreeMap, BTreeSet};
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use kurbo::{CubicBez, ParamCurve, PathSeg, Point, Rect, Vec2};
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use vectorcraft_geom::path::measured_arclen;
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use vectorcraft_geom::{Anchor, AnchorKind, PathData, SubPath};
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use crate::boolean::{Seg, segs_to_subpath};
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use crate::fit::{end_tangent, fit_cubics, fit_single, fit_single_from, is_straight, largest_second_difference, sample, start_tangent, unit};
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/// Options for [`simplify_with`].
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#[derive(Clone, Copy, Debug, PartialEq)]
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pub struct SimplifyOptions {
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/// Maximum distance (document points) between the original and simplified path.
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pub tolerance: f64,
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/// Anchors where the path turns by more than this many degrees stay corners.
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pub corner_angle_deg: f64,
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/// Produce only straight segments ("Convert to Straight Lines").
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pub straight_lines: bool,
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/// How far (points, the spread of a Gaussian along the path) the path is smoothed before it is
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/// refitted, so that bumps and jags come out as one curve ([`smooth_level`]); 0 for none.
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pub smooth: f64,
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}
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impl Default for SimplifyOptions {
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fn default() -> Self {
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Self { tolerance: 0.5, corner_angle_deg: 30.0, straight_lines: false, smooth: 0.0 }
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}
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}
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/// Simplify with the default corner threshold (30°).
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pub fn simplify(path: &PathData, tolerance: f64) -> PathData {
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simplify_with(path, &SimplifyOptions { tolerance, ..Default::default() })
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}
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/// The Simplify slider's level for a tolerance of 1 pt, the middle of its scale.
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pub const SIMPLIFY_LEVEL: f64 = 50.0;
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/// The tolerance (points) of Simplify slider level `level`, from 0 (the fewest anchor points) to
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/// 100 (the closest to the original): 1 pt at [`SIMPLIFY_LEVEL`], doubled for every 10 levels below
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/// it and halved for every 10 above, so level 0 is 32 pt and level 100 is 1/32 pt. A level outside
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/// 0..=100 counts as the nearer end, and one that is not a number counts as [`SIMPLIFY_LEVEL`].
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pub fn simplify_level_tolerance(level: f64) -> f64 {
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let level = if level.is_finite() { level.clamp(0.0, 100.0) } else { SIMPLIFY_LEVEL };
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((SIMPLIFY_LEVEL - level) / 10.0).exp2()
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}
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/// Auto-Simplify's level for paths whose bounds are `size` points on their longer side: the lowest
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/// whole level whose tolerance ([`simplify_level_tolerance`]) is at most 1/400 of `size`. It returns
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/// level 100 for a size of 0 or one that is not a number, and for a size under 12.5 pt, where no
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/// level is that close.
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pub fn auto_simplify_level(size: f64) -> f64 {
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let target = size / 400.0;
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if !(target.is_finite() && target > 0.0) {
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return 100.0;
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}
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(SIMPLIFY_LEVEL - 10.0 * target.log2()).ceil().clamp(0.0, 100.0)
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}
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/// Simplify never adds anchors: keep whichever subpath is smaller.
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fn no_worse(original: &SubPath, fitted: SubPath) -> SubPath {
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if fitted.anchors.len() > original.anchors.len() { original.clone() } else { fitted }
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}
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fn subpath_segs(sp: &SubPath) -> Vec<Seg> {
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(0..sp.segment_count()).map(|i| Seg { c: sp.segment(i), line: sp.segment_is_line(i) }).collect()
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}
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fn turn_deg(a: &Seg, b: &Seg) -> f64 {
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let d = end_tangent(&a.c).dot(start_tangent(&b.c)).clamp(-1.0, 1.0);
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d.acos().to_degrees()
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}
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/// Least-squares Bézier refit of every subpath, keeping corners sharper than the threshold.
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pub fn simplify_with(path: &PathData, opts: &SimplifyOptions) -> PathData {
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let mut out = Vec::new();
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for sp in &path.subpaths {
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if let Some(s) = simplify_subpath(sp, opts) {
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out.push(s);
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}
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}
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PathData::new(out)
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}
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/// [`simplify_with`] for one subpath; `None` when the refit leaves nothing of it.
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fn simplify_subpath(sp: &SubPath, opts: &SimplifyOptions) -> Option<SubPath> {
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let mut segs = subpath_segs(sp);
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let n = segs.len();
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if n == 0 {
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return Some(sp.clone());
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}
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if sp.closed {
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// Start the loop at its first corner, so no fit runs across one.
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let k = (0..n).find(|&i| turn_deg(&segs[(i + n - 1) % n], &segs[i]) > opts.corner_angle_deg).unwrap_or(0);
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segs.rotate_left(k);
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}
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// A smoothed loop with no corner is fitted along one direction across its start, when no segment
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// stays as it is and the fit has one part. A nearly straight first or last curve becomes a line
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// along its chord, and `no_worse` can return the original subpath, so the start can keep a kink.
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let across = if sp.closed && opts.smooth > 0.0 { unit(end_tangent(&segs[n - 1].c) + start_tangent(&segs[0].c)) } else { None };
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let across = across.filter(|_| (0..n).all(|i| turn_deg(&segs[(i + n - 1) % n], &segs[i]) <= opts.corner_angle_deg));
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let result = simplify_run_within(&segs, opts, MAX_RUN_SAMPLES, across);
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let s = segs_to_subpath(&result, sp.closed)?;
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Some(if opts.straight_lines { s } else { no_worse(sp, s) })
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}
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/// How far a segment may be from the lines between its samples, as a share of the tolerance.
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const SAMPLE_GAP: f64 = 0.005;
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/// Most samples of one segment. A segment that needs more stays as it is.
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const MAX_SEGMENT_SAMPLES: usize = 1 << 16;
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/// Most samples of one fit, which limits the memory a fit holds. A run with more is fitted in parts,
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/// with an anchor between them.
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pub(crate) const MAX_FIT_SAMPLES: usize = 1 << 20;
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/// Most samples of one run, which limits its time. The segments after the run reaches this stay as
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/// they are.
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const MAX_RUN_SAMPLES: usize = 1 << 24;
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/// Most segments of the result of one run before its other segments stay as they are, which limits
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/// the memory it holds. A fit under way can add up to [`MAX_FIT_SAMPLES`] more.
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pub(crate) const MAX_RUN_RESULT: usize = 1 << 21;
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/// How many evenly spaced steps along `c` keep it within [`SAMPLE_GAP`] of `tol` from the lines
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/// between its samples. Over a step of `1 / m`, a curve stays within `0.75 * s / (m * m)` of the line
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/// between its ends, where `s` is its largest second difference. The samples of a straight segment
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/// are on its line, so their spacing follows its length and `tol`, up to 256.
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pub(crate) fn sample_steps(c: &CubicBez, tol: f64) -> usize {
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// Guarded: kurbo subdivides without end on huge finite coordinates.
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let len = measured_arclen(&PathSeg::Cubic(*c), 1e-6);
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let by_length = ((len / (tol * 0.5)).ceil() as usize).clamp(4, 256);
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if is_straight(c, tol * SAMPLE_GAP * 0.5) {
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return by_length;
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}
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by_length.max((0.75 * largest_second_difference(c) / (tol * SAMPLE_GAP)).sqrt().ceil() as usize)
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}
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/// How many evenly spaced straight lines keep `c` within `tol` of them.
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fn line_steps(c: &CubicBez, tol: f64) -> usize {
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(0.75 * largest_second_difference(c) / tol).sqrt().ceil() as usize
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}
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/// The refit of the consecutive segments `run`, split at its corners sharper than the threshold:
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/// it starts and ends where `run` does, leaving the same way.
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fn simplify_run(run: &[Seg], opts: &SimplifyOptions) -> Vec<Seg> {
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simplify_run_within(run, opts, MAX_RUN_SAMPLES, None)
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}
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/// [`simplify_run`] with at most `budget` samples. A segment that needs more samples than
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/// [`MAX_SEGMENT_SAMPLES`] or than the budget has left, or that comes after [`MAX_RUN_RESULT`] segments
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/// of result, stays as it is, and the segments on each side of it are refitted without it. With
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/// `straight_lines` such a segment becomes [`line_steps`] lines, or as many as those limits allow when
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/// that is fewer, and then it can pass the tolerance. `ends`, when the whole run is refitted as one
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/// part, is the direction the refit leaves and arrives along.
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pub(crate) fn simplify_run_within(run: &[Seg], opts: &SimplifyOptions, mut budget: usize, ends: Option<Vec2>) -> Vec<Seg> {
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let tol = opts.tolerance.max(1e-6);
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let mut cuts: Vec<usize> = (1..run.len()).filter(|&i| turn_deg(&run[i - 1], &run[i]) > opts.corner_angle_deg).collect();
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cuts.insert(0, 0);
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cuts.push(run.len());
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let mut result: Vec<Seg> = Vec::new();
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for w in cuts.windows(2) {
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let piece = &run[w[0]..w[1]];
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let mut part: Vec<(&Seg, usize)> = Vec::new();
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let mut part_samples = 0;
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for s in piece {
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let steps = sample_steps(&s.c, tol);
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if steps <= budget.min(MAX_SEGMENT_SAMPLES) && result.len() < MAX_RUN_RESULT {
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if part_samples + steps > MAX_FIT_SAMPLES {
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refit_part(&part, opts, tol, None, &mut result);
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part.clear();
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part_samples = 0;
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}
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budget -= steps;
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part_samples += steps;
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part.push((s, steps));
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} else {
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part_samples = 0;
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refit_part(&part, opts, tol, None, &mut result);
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part.clear();
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if opts.straight_lines {
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let room = MAX_RUN_RESULT.saturating_sub(result.len());
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let lines = line_steps(&s.c, tol).min(budget.min(MAX_SEGMENT_SAMPLES)).min(room).max(1);
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budget = budget.saturating_sub(lines);
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let mut pts = Vec::new();
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sample(&s.c, lines, &mut pts, true);
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result.extend(pts.windows(2).map(|p| Seg::line(p[0], p[1])));
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} else {
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result.push(*s);
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}
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}
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}
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refit_part(&part, opts, tol, ends.filter(|_| part.len() == run.len()), &mut result);
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}
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result
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}
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/// Adds the refit of `part`, consecutive segments with no corner between them and the steps to
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/// sample each one with, to `result`. `ends` is the direction it leaves and arrives along, when not
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/// those of its first and last segments.
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fn refit_part(part: &[(&Seg, usize)], opts: &SimplifyOptions, tol: f64, ends: Option<Vec2>, result: &mut Vec<Seg>) {
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let (Some((first, _)), Some((last, _))) = (part.first(), part.last()) else { return };
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let mut pts = Vec::new();
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for (k, (s, steps)) in part.iter().enumerate() {
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sample(&s.c, *steps, &mut pts, k == 0);
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}
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if opts.smooth > 0.0 {
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pts = smooth_points(&pts, opts.smooth);
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}
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if opts.straight_lines {
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let keep = rdp(&pts, tol * (1.0 - SAMPLE_GAP));
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result.extend(keep.windows(2).map(|p| Seg::line(p[0], p[1])));
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return;
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}
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// The fit may be `tol * 0.98` from the lines between the samples, those lines may be
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// `SAMPLE_GAP` of `tol` from the path, and the curve the test below turns into a line moves by up
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// to 1.5% of `tol`: 3/4 of how far its handles may be from the line.
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let (t0, t1) = ends.map_or((start_tangent(&first.c), end_tangent(&last.c)), |d| (d, d));
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for c in fit_cubics(&pts, t0, t1, tol * 0.98) {
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let line = is_straight(&c, tol * 0.02);
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result.push(if line { Seg::line(c.p0, c.p3) } else { Seg { c, line } });
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}
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}
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/// `pts` (a run's samples, in order) smoothed along the path: each point becomes the Gaussian-weighted
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/// mean of the points around it, `sigma` points of arc length wide, the window narrowing towards the
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/// ends so that the first and last points stay where they are. Consecutive samples within
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/// 1/[`SMOOTH_GROUP`] of a spread of each other along the path are weighed together, as their count at
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/// their mean place, so the work per point is bounded by the groups within three spreads of it however
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/// densely the path is sampled.
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fn smooth_points(pts: &[Point], sigma: f64) -> Vec<Point> {
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smooth_points_counted(pts, sigma, &mut 0)
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}
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/// How many groups of samples a spread holds at most in [`smooth_points`]. Weighing them in groups
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/// leaves each smoothed point within a thousandth of a spread of the mean of its samples weighed one
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/// by one.
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const SMOOTH_GROUP: f64 = 16.0;
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/// [`smooth_points`], adding the number of sample groups it looks at to `work`.
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fn smooth_points_counted(pts: &[Point], sigma: f64, work: &mut usize) -> Vec<Point> {
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let Some(&origin) = pts.first() else { return Vec::new() };
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if pts.len() < 3 || !(sigma.is_finite() && sigma > 0.0) {
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return pts.to_vec();
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}
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let mut s = Vec::with_capacity(pts.len());
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let mut total = 0.0;
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for (i, p) in pts.iter().enumerate() {
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if let Some(prev) = i.checked_sub(1).and_then(|j| pts.get(j)) {
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total += prev.distance(*p);
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}
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s.push(total);
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}
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let groups = SampleGroups::new(pts, &s, origin);
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let (mut lo, mut hi) = (0usize, 0usize);
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pts.iter()
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.zip(&s)
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.map(|(&p, &si)| {
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let reach = (3.0 * sigma).min(si).min(total - si);
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if reach <= 1e-9 {
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return p;
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}
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let spread = reach / 3.0;
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while s.get(lo).is_some_and(|&v| v < si - reach) {
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lo += 1;
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}
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while s.get(hi + 1).is_some_and(|&v| v <= si + reach) {
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hi += 1;
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}
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let window = Window { lo, end: hi + 1, at: si, spread, group: spread / SMOOTH_GROUP };
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let mut acc = Weighed::default();
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groups.weigh(0, (0, pts.len()), &window, &mut acc);
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*work += acc.work;
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if acc.weight > 0.0 { origin + acc.sum / acc.weight } else { p }
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})
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.collect()
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}
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/// The samples [`smooth_points`] weighs for one point: indices `lo..end`, weighed by a Gaussian of
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/// `spread` around arc length `at`, in groups at most `group` long along the path.
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struct Window {
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lo: usize,
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end: usize,
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at: f64,
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spread: f64,
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group: f64,
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}
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/// The sums of halves, quarters and so on of a run's samples, by index: node 0 holds all of them and
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/// node `k`'s halves are nodes `2k + 1` and `2k + 2`.
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struct SampleGroups<'a> {
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/// Arc length of each sample.
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s: &'a [f64],
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/// Sum of the arc lengths of each node's samples.
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sum_s: Vec<f64>,
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/// Sum of each node's samples, measured from the first sample.
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sum_q: Vec<Vec2>,
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}
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impl<'a> SampleGroups<'a> {
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fn new(pts: &[Point], s: &'a [f64], origin: Point) -> Self {
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let size = 4 * pts.len();
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let mut groups = Self { s, sum_s: vec![0.0; size], sum_q: vec![Vec2::ZERO; size] };
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groups.build(0, 0, pts.len(), pts, origin);
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groups
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}
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fn build(&mut self, node: usize, l: usize, r: usize, pts: &[Point], origin: Point) {
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if r <= l {
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return;
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}
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let (sum_s, sum_q) = if r - l == 1 {
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(self.s.get(l).copied().unwrap_or(0.0), pts.get(l).map_or(Vec2::ZERO, |&p| p - origin))
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} else {
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let m = l + (r - l) / 2;
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self.build(2 * node + 1, l, m, pts, origin);
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self.build(2 * node + 2, m, r, pts, origin);
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let at = |v: &Vec<f64>, k: usize| v.get(k).copied().unwrap_or(0.0);
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let q = |k: usize| self.sum_q.get(k).copied().unwrap_or(Vec2::ZERO);
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(at(&self.sum_s, 2 * node + 1) + at(&self.sum_s, 2 * node + 2), q(2 * node + 1) + q(2 * node + 2))
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};
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if let Some(a) = self.sum_s.get_mut(node) {
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*a = sum_s;
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}
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if let Some(a) = self.sum_q.get_mut(node) {
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*a = sum_q;
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}
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}
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/// Adds the weighted samples of node `node` (indices `l..r`) that are inside `w` to `acc`: a node
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/// inside `w` no longer than its groups as its count at its mean arc length, any other node by
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/// its halves.
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fn weigh(&self, node: usize, (l, r): (usize, usize), w: &Window, acc: &mut Weighed) {
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if r <= w.lo || l >= w.end || r <= l {
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return;
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}
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acc.work += 1;
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let length = self.s.get(r - 1).copied().unwrap_or(0.0) - self.s.get(l).copied().unwrap_or(0.0);
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// One sample is always a group, even where arc lengths that overflowed leave `length` NaN.
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if r - l == 1 || (w.lo <= l && r <= w.end && length <= w.group) {
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let count = (r - l) as f64;
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let t = self.sum_s.get(node).copied().unwrap_or(0.0) / count - w.at;
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let g = (-t * t / (2.0 * w.spread * w.spread)).exp();
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acc.sum += self.sum_q.get(node).copied().unwrap_or(Vec2::ZERO) * g;
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acc.weight += count * g;
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return;
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}
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let m = l + (r - l) / 2;
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self.weigh(2 * node + 1, (l, m), w, acc);
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self.weigh(2 * node + 2, (m, r), w, acc);
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}
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}
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/// What [`SampleGroups::weigh`] has added up: the weighted sum of the samples (from the first
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/// sample), the sum of the weights, and the number of nodes looked at.
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#[derive(Default)]
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struct Weighed {
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sum: Vec2,
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weight: f64,
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work: usize,
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}
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/// What [`simplify_part`] made of a path.
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#[derive(Clone, Debug, PartialEq)]
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pub struct SimplifiedPart {
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pub path: PathData,
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/// The segments of the simplified runs, as (subpath, segment) in `path`.
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pub segments: BTreeSet<(usize, usize)>,
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/// Where each anchor of the original path that is still there went: (subpath, anchor) in the
|
||
/// original → in `path`. Anchors inside a simplified run are gone; every other anchor is kept.
|
||
pub anchors: BTreeMap<(usize, usize), (usize, usize)>,
|
||
}
|
||
|
||
/// Simplify only the `segments` (subpath, segment) of `path`: each run of consecutive segments
|
||
/// among them (a closed subpath's run may cross its start point) is refitted on its own between its
|
||
/// two end anchors, which stay where they are with their handles on the side away from the run.
|
||
/// The other segments and anchors stay exactly as they are. A subpath whose every segment is in
|
||
/// `segments` is simplified whole, as [`simplify_with`] does. A run whose refit would have more
|
||
/// segments than it had is left as it is (except with Convert to Straight Lines).
|
||
pub fn simplify_part(path: &PathData, segments: &BTreeSet<(usize, usize)>, opts: &SimplifyOptions) -> SimplifiedPart {
|
||
let (mut runs, mut anchors) = (BTreeSet::new(), BTreeMap::new());
|
||
let mut subpaths = Vec::with_capacity(path.subpaths.len());
|
||
for (si, sp) in path.subpaths.iter().enumerate() {
|
||
let n = sp.segment_count();
|
||
let picked: Vec<bool> = (0..n).map(|i| segments.contains(&(si, i))).collect();
|
||
let ni = subpaths.len();
|
||
if !picked.contains(&true) {
|
||
anchors.extend((0..sp.anchors.len()).map(|ai| ((si, ai), (ni, ai))));
|
||
subpaths.push(sp.clone());
|
||
} else if !picked.contains(&false) {
|
||
if let Some(s) = simplify_subpath(sp, opts) {
|
||
runs.extend((0..s.segment_count()).map(|i| (ni, i)));
|
||
subpaths.push(s);
|
||
}
|
||
} else {
|
||
let (s, segs, kept) = simplify_runs(sp, &picked, opts);
|
||
runs.extend(segs.into_iter().map(|i| (ni, i)));
|
||
anchors.extend(kept.into_iter().map(|(old, new)| ((si, old), (ni, new))));
|
||
subpaths.push(s);
|
||
}
|
||
}
|
||
SimplifiedPart { path: PathData::new(subpaths), segments: runs, anchors }
|
||
}
|
||
|
||
/// [`simplify_part`] for a subpath with some but not all segments `picked`: → (the subpath, the
|
||
/// segments of its refitted runs, old → new index of each anchor kept).
|
||
fn simplify_runs(sp: &SubPath, picked: &[bool], opts: &SimplifyOptions) -> (SubPath, Vec<usize>, Vec<(usize, usize)>) {
|
||
let m = sp.anchors.len();
|
||
let n = picked.len();
|
||
// An anchor inside a run (both its segments picked) goes; a closed subpath's walk starts at the
|
||
// first anchor that stays, so that no run crosses the start of the walk.
|
||
let inside = |a: usize| (sp.closed && a == 0 && picked[n - 1] && picked[0]) || (a > 0 && a < n && picked[a - 1] && picked[a]);
|
||
let start = (0..m).find(|&a| !inside(a)).unwrap_or(0);
|
||
let mut anchors = vec![sp.anchors[start]];
|
||
let mut kept = vec![(start, 0)];
|
||
let mut runs = vec![];
|
||
let mut k = 0;
|
||
while k < n {
|
||
let j = (start + k) % n;
|
||
if !picked[j] {
|
||
let next = (j + 1) % m;
|
||
if k + 1 < n || !sp.closed {
|
||
kept.push((next, anchors.len()));
|
||
anchors.push(sp.anchors[next]);
|
||
}
|
||
k += 1;
|
||
continue;
|
||
}
|
||
let len = (k..n).take_while(|&i| picked[(start + i) % n]).count();
|
||
let run: Vec<Seg> = (k..k + len).map(|i| (start + i) % n).map(|i| Seg { c: sp.segment(i), line: sp.segment_is_line(i) }).collect();
|
||
let end = (start + k + len) % m;
|
||
let fitted = simplify_run(&run, opts);
|
||
let keep_original = fitted.is_empty() || !opts.straight_lines && fitted.len() > run.len();
|
||
let first = anchors.len() - 1;
|
||
if keep_original {
|
||
anchors.extend((k + 1..k + len).map(|i| sp.anchors[(start + i) % m]));
|
||
} else {
|
||
let a = anchors[first];
|
||
anchors[first] = with_handle(a, true, if fitted[0].line { a.p } else { fitted[0].c.p1 });
|
||
for w in fitted.windows(2) {
|
||
let p = w[1].c.p0;
|
||
let h_in = if w[0].line { p } else { w[0].c.p2 };
|
||
let h_out = if w[1].line { p } else { w[1].c.p1 };
|
||
anchors.push(Anchor::with_handles(p, h_in, h_out));
|
||
}
|
||
}
|
||
// The run's segments, from its first anchor on: a run back to the walk's start ends with
|
||
// the closing segment, the last index.
|
||
runs.extend(first..first + if keep_original { run.len() } else { fitted.len() });
|
||
let end_seg = fitted.last().filter(|_| !keep_original);
|
||
if sp.closed && k + len == n {
|
||
// The run ends where the walk started.
|
||
if let Some(s) = end_seg {
|
||
anchors[0] = with_handle(anchors[0], false, if s.line { anchors[0].p } else { s.c.p2 });
|
||
}
|
||
} else {
|
||
let a = sp.anchors[end];
|
||
kept.push((end, anchors.len()));
|
||
anchors.push(match end_seg {
|
||
Some(s) => with_handle(a, false, if s.line { a.p } else { s.c.p2 }),
|
||
None => a,
|
||
});
|
||
}
|
||
k += len;
|
||
}
|
||
(SubPath::new(anchors, sp.closed), runs, kept)
|
||
}
|
||
|
||
/// `a` with its out (`out`) or in handle at `h` and the other as it is: still smooth when it was
|
||
/// and its handles still line up, a corner otherwise.
|
||
fn with_handle(a: Anchor, out: bool, h: Point) -> Anchor {
|
||
let (h_in, h_out) = if out { (a.h_in, h) } else { (h, a.h_out) };
|
||
let kind = if a.kind == AnchorKind::Smooth { Anchor::with_handles(a.p, h_in, h_out).kind } else { AnchorKind::Corner };
|
||
Anchor { p: a.p, h_in, h_out, kind }
|
||
}
|
||
|
||
/// Ramer–Douglas–Peucker polyline reduction. Each point dropped is within `tol` of the line segment
|
||
/// that replaces it: a point beyond either end of the segment is measured to that end.
|
||
fn rdp(pts: &[Point], tol: f64) -> Vec<Point> {
|
||
if pts.len() < 3 {
|
||
return pts.to_vec();
|
||
}
|
||
let mut keep = vec![false; pts.len()];
|
||
keep[0] = true;
|
||
keep[pts.len() - 1] = true;
|
||
let mut stack = vec![(0, pts.len() - 1)];
|
||
// Distances measured at most: lopsided splits (a shallow zigzag) make it quadratic. Past it,
|
||
// the points of the parts left are kept as they are.
|
||
let mut budget = pts.len().saturating_mul(64).saturating_add(1 << 20);
|
||
while let Some((a, b)) = stack.pop() {
|
||
budget = match budget.checked_sub(b - a) {
|
||
Some(left) => left,
|
||
None => {
|
||
keep[a..=b].fill(true);
|
||
continue;
|
||
}
|
||
};
|
||
let (pa, pb) = (pts[a], pts[b]);
|
||
let chord = pb - pa;
|
||
let len2 = chord.hypot2();
|
||
let mut best = (0.0, a);
|
||
for (i, &p) in pts.iter().enumerate().take(b).skip(a + 1) {
|
||
let d = if len2 < 1e-24 { p.distance(pa) } else { p.distance(pa + chord * ((p - pa).dot(chord) / len2).clamp(0.0, 1.0)) };
|
||
if d > best.0 {
|
||
best = (d, i);
|
||
}
|
||
}
|
||
if best.0 > tol {
|
||
keep[best.1] = true;
|
||
stack.push((a, best.1));
|
||
stack.push((best.1, b));
|
||
}
|
||
}
|
||
pts.iter().zip(keep).filter(|(_, k)| *k).map(|(p, _)| *p).collect()
|
||
}
|
||
|
||
/// Object → Path → Smooth: pull handles towards Catmull-Rom-like tangents. `amount` ∈ [0, 1]
|
||
/// (0 = unchanged, 1 = fully smooth). Endpoints of open paths keep their handles.
|
||
pub fn smooth(path: &PathData, amount: f64) -> PathData {
|
||
let t = amount.clamp(0.0, 1.0);
|
||
let mut out = path.clone();
|
||
for sp in &mut out.subpaths {
|
||
let n = sp.anchors.len();
|
||
if n < 3 {
|
||
continue;
|
||
}
|
||
let orig = sp.anchors.clone();
|
||
for i in 0..n {
|
||
if !sp.closed && (i == 0 || i == n - 1) {
|
||
continue;
|
||
}
|
||
let prev = orig[(i + n - 1) % n].p;
|
||
let next = orig[(i + 1) % n].p;
|
||
let p = orig[i].p;
|
||
let Some(dir) = crate::fit::unit(next - prev) else { continue };
|
||
let tin = p - dir * (p.distance(prev) / 3.0);
|
||
let tout = p + dir * (p.distance(next) / 3.0);
|
||
let a = &orig[i];
|
||
let h_in = a.h_in.lerp(tin, t);
|
||
let h_out = a.h_out.lerp(tout, t);
|
||
sp.anchors[i] = Anchor::with_handles(p, h_in, h_out);
|
||
}
|
||
}
|
||
out
|
||
}
|
||
|
||
/// The Smooth slider's level Auto-Smooth picks, halfway between minimum and maximum smoothing.
|
||
/// VectorCraft's own rule: the help page says only that Auto-Smooth smooths the path automatically
|
||
/// (https://helpx.adobe.com/illustrator/desktop/draw-shapes-and-paths/modify-paths/refine-path-segments-with-the-smooth-slider.html).
|
||
/// [`smooth_level`] already scales with each path's size, so one level suits every path.
|
||
pub const SMOOTH_AUTO_LEVEL: f64 = 50.0;
|
||
|
||
/// The refit Object › Path › Smooth makes of `path` at slider level `level` ([`smooth_level`]): a
|
||
/// corner only where the path turns back on itself, the path smoothed along its length by up to 5 %
|
||
/// of its longer side (none at level 0) and refitted within 0.1 % (level 0) to 2.5 % (level 100) of
|
||
/// it. A level outside 0..=100 counts as the nearer end, and one that is not a number as
|
||
/// [`SMOOTH_AUTO_LEVEL`]; a path of no finite size gets no smoothing.
|
||
pub fn smooth_options(path: &PathData, level: f64) -> SimplifyOptions {
|
||
let level = if level.is_finite() { level.clamp(0.0, 100.0) } else { SMOOTH_AUTO_LEVEL };
|
||
let size = path.bounds().map_or(0.0, |b| b.width().max(b.height()));
|
||
let size = if size.is_finite() { size } else { 0.0 };
|
||
SimplifyOptions {
|
||
tolerance: size * (0.001 + 0.024 * level / 100.0),
|
||
corner_angle_deg: SMOOTH_CORNER_DEG,
|
||
straight_lines: false,
|
||
smooth: size * 0.05 * level / 100.0,
|
||
}
|
||
}
|
||
|
||
/// Object › Path › Smooth at slider level `level`, from 0 (minimum smoothing: the path stays within
|
||
/// 0.1 % of its longer side of where it was) to 100 (maximum). The help page names only the two
|
||
/// ends; the rest is VectorCraft's own rule ([`smooth_options`]). Each subpath is smoothed along its
|
||
/// length, so that bumps and jags give way to one curve, then refitted with curves as Simplify
|
||
/// does, keeping a corner only where the path turns back on itself. A refit never has more anchor
|
||
/// points than the subpath had: a shape whose corners it can't round, such as a rectangle, stays as
|
||
/// it is. Closed subpaths stay closed, with no kink left where they start unless rounding it would
|
||
/// pass the tolerance, and open ones keep their end points.
|
||
pub fn smooth_level(path: &PathData, level: f64) -> PathData {
|
||
let opts = smooth_options(path, level);
|
||
if opts.tolerance <= 0.0 {
|
||
return path.clone();
|
||
}
|
||
let smoothed = |sp: &SubPath| {
|
||
let Some(mut fit) = simplify_subpath(sp, &opts).filter(|f| f != sp) else { return sp.clone() };
|
||
smooth_seam(&mut fit, sp, opts.tolerance);
|
||
fit
|
||
};
|
||
PathData::new(path.subpaths.iter().map(smoothed).collect())
|
||
}
|
||
|
||
/// [`smooth_level`] keeps a corner only where the path turns by more than this (turns back).
|
||
const SMOOTH_CORNER_DEG: f64 = 179.0;
|
||
|
||
/// A closed subpath's refit leaves its start anchor with the tangents of the original segments on
|
||
/// either side of it, a kink when the path had one there: turn it into a smooth anchor with the same
|
||
/// handle lengths, unless the path turns back there or the rounded path would stray from `original`
|
||
/// by more than `tol` (or than the refit already does).
|
||
fn smooth_seam(sp: &mut SubPath, original: &SubPath, tol: f64) {
|
||
if !sp.closed {
|
||
return;
|
||
}
|
||
let Some(a) = sp.anchors.first() else { return };
|
||
let (Some(i), Some(o)) = (crate::fit::unit(a.p - a.h_in), crate::fit::unit(a.h_out - a.p)) else { return };
|
||
if i.dot(o) < SMOOTH_CORNER_DEG.to_radians().cos() {
|
||
return;
|
||
}
|
||
let Some(dir) = crate::fit::unit(i + o) else { return };
|
||
let mut rounded = sp.clone();
|
||
if let Some(r) = rounded.anchors.first_mut() {
|
||
*r = Anchor::with_handles(a.p, a.p - dir * a.h_in.distance(a.p), a.p + dir * a.h_out.distance(a.p));
|
||
}
|
||
if seam_error(original, sp, &rounded, tol) <= tol.max(seam_error(original, sp, sp, tol)) {
|
||
*sp = rounded;
|
||
}
|
||
}
|
||
|
||
/// How far the segments on either side of the start anchor of `fit` (a refit of the closed
|
||
/// `original` whose other segments match `before`) are from `original`, both ways: the largest
|
||
/// distance from those segments to `original`, and from the parts of `original` that `before`'s
|
||
/// segments there cover (within `tol`) to `fit`.
|
||
fn seam_error(original: &SubPath, before: &SubPath, fit: &SubPath, tol: f64) -> f64 {
|
||
use kurbo::ParamCurveNearest;
|
||
let n = fit.segment_count();
|
||
if n == 0 || before.segment_count() != n || original.segment_count() == 0 {
|
||
return f64::INFINITY;
|
||
}
|
||
let is_seam = |j: usize| j == 0 || j + 1 == n;
|
||
let dist = |q: Point, sp: &SubPath, seam: bool| {
|
||
(0..sp.segment_count())
|
||
.filter(|&j| is_seam(j) == seam)
|
||
.map(|j| sp.segment(j).nearest(q, 1e-9).distance_sq)
|
||
.fold(f64::INFINITY, f64::min)
|
||
.sqrt()
|
||
};
|
||
let samples = |sp: &SubPath, seam_only: bool| {
|
||
let mut pts = Vec::new();
|
||
for j in (0..sp.segment_count()).filter(|&j| !seam_only || is_seam(j)) {
|
||
let c = sp.segment(j);
|
||
let m = ((measured_arclen(&PathSeg::Cubic(c), 1e-6) / (tol.max(1e-6) * 0.5)).ceil() as usize).clamp(4, 256);
|
||
sample(&c, m, &mut pts, true);
|
||
}
|
||
pts
|
||
};
|
||
let all = |q: Point| dist(q, original, true).min(dist(q, original, false));
|
||
let forward = samples(fit, true).into_iter().map(all).fold(0.0, f64::max);
|
||
let back = samples(original, false)
|
||
.into_iter()
|
||
.filter(|&q| dist(q, before, true) <= tol)
|
||
.map(|q| {
|
||
let d = dist(q, fit, true);
|
||
if d > tol { d.min(dist(q, fit, false)) } else { d }
|
||
})
|
||
.fold(0.0, f64::max);
|
||
forward.max(back)
|
||
}
|
||
|
||
/// Remove anchors that can be deleted without changing the shape by more than `tolerance`
|
||
/// (collinear corner points, duplicate points, and curve joints that one cubic can replace).
|
||
pub fn remove_redundant_points(path: &PathData, tolerance: f64) -> PathData {
|
||
let tol = tolerance.max(1e-9);
|
||
let mut out = Vec::new();
|
||
for sp in &path.subpaths {
|
||
let mut segs = subpath_segs(sp);
|
||
if segs.is_empty() {
|
||
out.push(sp.clone());
|
||
continue;
|
||
}
|
||
// Drop zero-length segments.
|
||
segs.retain(|s| !(s.c.p0.distance(s.c.p3) < 1e-9 && s.c.p1.distance(s.c.p0) < 1e-9 && s.c.p2.distance(s.c.p0) < 1e-9));
|
||
let min_segs = if sp.closed { 2 } else { 1 };
|
||
// Joints are merged along the path in one pass (a merged segment is tried with the one
|
||
// before it, then the next); the search below then only finds what a closed path's wrap
|
||
// leaves. (Merging at the first joint of a dense line one at a time shifts the rest each time.)
|
||
let total = segs.len();
|
||
let mut merged = 0;
|
||
let mut done: Vec<Seg> = Vec::with_capacity(total);
|
||
for s in segs.drain(..) {
|
||
done.push(s);
|
||
while done.len() >= 2 && total - merged > min_segs {
|
||
let n = done.len();
|
||
let Some(m) = merge_pair(&done[n - 2], &done[n - 1], tol) else { break };
|
||
done.truncate(n - 1);
|
||
done[n - 2] = m;
|
||
merged += 1;
|
||
}
|
||
}
|
||
segs = done;
|
||
let mut changed = true;
|
||
while changed && segs.len() > min_segs {
|
||
changed = false;
|
||
let n = segs.len();
|
||
let joints = if sp.closed { n } else { n - 1 };
|
||
for j in 0..joints {
|
||
let (i0, i1) = if sp.closed { ((j + n - 1) % n, j) } else { (j, j + 1) };
|
||
if let Some(m) = merge_pair(&segs[i0], &segs[i1], tol) {
|
||
segs[i0] = m;
|
||
segs.remove(i1);
|
||
if sp.closed && i1 == 0 {
|
||
// The merged segment now starts the loop.
|
||
if let Some(last) = segs.pop() {
|
||
segs.insert(0, last);
|
||
}
|
||
}
|
||
changed = true;
|
||
break;
|
||
}
|
||
}
|
||
}
|
||
if let Some(s) = segs_to_subpath(&segs, sp.closed) {
|
||
out.push(s);
|
||
}
|
||
}
|
||
PathData::new(out)
|
||
}
|
||
|
||
fn merge_pair(a: &Seg, b: &Seg, tol: f64) -> Option<Seg> {
|
||
if a.line && b.line {
|
||
let chord = b.c.p3 - a.c.p0;
|
||
let len = chord.hypot();
|
||
if len < 1e-12 {
|
||
return None;
|
||
}
|
||
let mid = a.c.p3 - a.c.p0;
|
||
let along = mid.dot(chord) / len;
|
||
return ((mid.cross(chord) / len).abs() <= tol && along >= 0.0 && along <= len).then(|| Seg::line(a.c.p0, b.c.p3));
|
||
}
|
||
// Only merge across (near-)smooth joints.
|
||
if end_tangent(&a.c).dot(start_tangent(&b.c)) < 0.99 {
|
||
return None;
|
||
}
|
||
let mut pts = Vec::new();
|
||
sample(&a.c, 16, &mut pts, true);
|
||
sample(&b.c, 16, &mut pts, false);
|
||
let (c, err, _) = fit_single(&pts, start_tangent(&a.c), end_tangent(&b.c));
|
||
(err <= tol).then_some(Seg { c, line: false })
|
||
}
|
||
|
||
/// Remove anchor `index` without opening the path (the Delete Anchor Point tool and Object → Path
|
||
/// → Remove Anchor Points). Its neighbours keep their handle directions and their facing handles
|
||
/// are refitted so one cubic follows the two segments that met there; two straight segments
|
||
/// become one. Removing an end of an open path drops its segment. Returns false, leaving `sp`
|
||
/// alone, when `index` is out of range.
|
||
pub fn remove_anchor(sp: &mut SubPath, index: usize) -> bool {
|
||
let n = sp.anchors.len();
|
||
if index >= n {
|
||
return false;
|
||
}
|
||
if (sp.closed || (index > 0 && index + 1 < n)) && n >= 3 {
|
||
let (pi, ni) = ((index + n - 1) % n, (index + 1) % n);
|
||
if !(sp.segment_is_line(pi) && sp.segment_is_line(index)) {
|
||
let (left, right) = (sp.segment(pi), sp.segment(index));
|
||
const N: usize = 16;
|
||
let mut pts = Vec::with_capacity(2 * N + 1);
|
||
sample(&left, N, &mut pts, true);
|
||
sample(&right, N, &mut pts, false);
|
||
let (t0, t1) = (start_tangent(&left), end_tangent(&right));
|
||
// The new curve passes the removed point at some parameter k: the left samples sit
|
||
// at k·i/N, the right ones at k + (1 − k)·i/N. Search k for the closest fit.
|
||
let fit = |k: f64| {
|
||
let u = (0..=N).map(|i| k * i as f64 / N as f64).chain((1..=N).map(|i| k + (1.0 - k) * i as f64 / N as f64)).collect();
|
||
fit_single_from(&pts, u, t0, t1)
|
||
};
|
||
let (c, _, _) = golden_min(fit, 0.0, 1.0);
|
||
if c.p1.is_finite() && c.p2.is_finite() {
|
||
sp.anchors[pi].h_out = c.p1;
|
||
sp.anchors[ni].h_in = c.p2;
|
||
}
|
||
}
|
||
}
|
||
sp.anchors.remove(index);
|
||
if !sp.closed {
|
||
// A new end has nothing beyond it.
|
||
if let Some(a) = sp.anchors.first_mut() {
|
||
a.h_in = a.p;
|
||
}
|
||
if let Some(a) = sp.anchors.last_mut() {
|
||
a.h_out = a.p;
|
||
}
|
||
}
|
||
if sp.anchors.len() < 3 {
|
||
sp.closed = sp.closed && sp.anchors.len() == 2 && sp.anchors.iter().any(|a| a.has_in() || a.has_out());
|
||
}
|
||
true
|
||
}
|
||
|
||
/// The fit `f` (curve, error, worst point) with the least error for an argument in `[a, b]`, by a
|
||
/// golden-section search (a bounded number of steps).
|
||
fn golden_min(f: impl Fn(f64) -> (CubicBez, f64, usize), mut a: f64, mut b: f64) -> (CubicBez, f64, usize) {
|
||
const R: f64 = 0.618_033_988_749_895;
|
||
let (mut x1, mut x2) = (b - R * (b - a), a + R * (b - a));
|
||
let (mut f1, mut f2) = (f(x1), f(x2));
|
||
for _ in 0..40 {
|
||
// A NaN error never wins.
|
||
if f1.1 < f2.1 || f2.1.is_nan() {
|
||
(b, x2, f2) = (x2, x1, f1);
|
||
x1 = b - R * (b - a);
|
||
f1 = f(x1);
|
||
} else {
|
||
(a, x1, f1) = (x1, x2, f2);
|
||
x2 = a + R * (b - a);
|
||
f2 = f(x2);
|
||
}
|
||
}
|
||
if f1.1 <= f2.1 { f1 } else { f2 }
|
||
}
|
||
|
||
/// Object → Path → Add Anchor Points: one new anchor at the middle (t = 0.5) of every segment.
|
||
pub fn add_anchor_points(path: &PathData) -> PathData {
|
||
let mut out = path.clone();
|
||
for sp in &mut out.subpaths {
|
||
let n = sp.segment_count();
|
||
if n == 0 {
|
||
continue;
|
||
}
|
||
// Built in one pass (inserting into the middle of the vector shifts the rest each time):
|
||
// anchor k lands at 2k and the new anchor of segment k at 2k + 1.
|
||
let mut v = Vec::with_capacity(sp.anchors.len() * 2);
|
||
for (k, a) in sp.anchors.iter().enumerate() {
|
||
v.push(*a);
|
||
if k < n {
|
||
v.push(*a);
|
||
}
|
||
}
|
||
for seg in 0..n {
|
||
let c = sp.segment(seg);
|
||
let (l, r) = (c.subsegment(0.0..0.5), c.subsegment(0.5..1.0));
|
||
if sp.segment_is_line(seg) {
|
||
v[2 * seg + 1] = Anchor::corner(l.p3);
|
||
} else {
|
||
let at = (2 * seg + 2) % v.len();
|
||
v[2 * seg].h_out = l.p1;
|
||
v[at].h_in = r.p2;
|
||
v[2 * seg + 1] = Anchor { p: l.p3, h_in: l.p2, h_out: r.p1, kind: AnchorKind::Smooth };
|
||
}
|
||
}
|
||
sp.anchors = v;
|
||
}
|
||
out
|
||
}
|
||
|
||
/// Axis for [`average`].
|
||
#[derive(Clone, Copy, Debug, PartialEq, Eq, Hash)]
|
||
pub enum AverageAxis {
|
||
/// Align on a common horizontal line (same y).
|
||
Horizontal,
|
||
/// Align on a common vertical line (same x).
|
||
Vertical,
|
||
/// Collapse to the common centroid.
|
||
Both,
|
||
}
|
||
|
||
/// Object → Path → Average: move the selected anchors `(subpath, anchor)` (with their handles)
|
||
/// to their average position along `axis`.
|
||
pub fn average(path: &PathData, selection: &[(usize, usize)], axis: AverageAxis) -> PathData {
|
||
let mut out = path.clone();
|
||
let pts: Vec<Point> = selection.iter().filter_map(|&(s, a)| path.subpaths.get(s).and_then(|sp| sp.anchors.get(a)).map(|a| a.p)).collect();
|
||
if pts.is_empty() {
|
||
return out;
|
||
}
|
||
let c = pts.iter().fold(Vec2::ZERO, |acc, p| acc + p.to_vec2()) / pts.len() as f64;
|
||
for &(s, a) in selection {
|
||
if let Some(an) = out.anchor_mut(s, a) {
|
||
let d = match axis {
|
||
AverageAxis::Horizontal => Vec2::new(0.0, c.y - an.p.y),
|
||
AverageAxis::Vertical => Vec2::new(c.x - an.p.x, 0.0),
|
||
AverageAxis::Both => c - an.p.to_vec2(),
|
||
};
|
||
an.translate(d);
|
||
}
|
||
}
|
||
out
|
||
}
|
||
|
||
/// Object → Path → Join. Open subpaths of all inputs are joined nearest-endpoint-first into one
|
||
/// open path (endpoints closer than `tolerance` are merged into a single anchor, otherwise a
|
||
/// straight segment connects them). A single open subpath is closed instead. Closed subpaths
|
||
/// pass through unchanged.
|
||
pub fn join(paths: &[PathData], tolerance: f64) -> PathData {
|
||
let mut closed: Vec<SubPath> = Vec::new();
|
||
let mut open: Vec<SubPath> = Vec::new();
|
||
for p in paths {
|
||
for sp in &p.subpaths {
|
||
if sp.closed || sp.anchors.len() < 2 {
|
||
if !sp.anchors.is_empty() {
|
||
closed.push(sp.clone());
|
||
}
|
||
} else {
|
||
open.push(sp.clone());
|
||
}
|
||
}
|
||
}
|
||
if open.len() == 1
|
||
&& let Some(mut sp) = open.pop()
|
||
{
|
||
let ends_meet = sp.anchors.len() > 2 && end_point(&sp, false).zip(end_point(&sp, true)).is_some_and(|(a, b)| a.distance(b) <= tolerance);
|
||
if ends_meet
|
||
&& let Some(last) = sp.anchors.pop()
|
||
&& let Some(f) = sp.anchors.first_mut()
|
||
{
|
||
*f = Anchor::with_handles(f.p, last.h_in, f.h_out);
|
||
} else {
|
||
if let Some(f) = sp.anchors.first_mut() {
|
||
f.h_in = f.p;
|
||
}
|
||
if let Some(l) = sp.anchors.last_mut() {
|
||
l.h_out = l.p;
|
||
}
|
||
}
|
||
sp.closed = true;
|
||
closed.push(sp);
|
||
return PathData::new(closed);
|
||
}
|
||
while open.len() > 1 {
|
||
// Find the closest pair of endpoints on different subpaths. Past this many subpaths every
|
||
// pair at every merge is too much (cubic): the first one is joined to its nearest.
|
||
const SEARCH_ALL: usize = 200;
|
||
let first_only = open.len() > SEARCH_ALL;
|
||
let mut best = (f64::INFINITY, 0, 0, false, false);
|
||
for i in 0..if first_only { 1 } else { open.len() } {
|
||
for j in (i + 1)..open.len() {
|
||
for ei in [false, true] {
|
||
for ej in [false, true] {
|
||
let (Some(pi), Some(pj)) = (end_point(&open[i], ei), end_point(&open[j], ej)) else { continue };
|
||
let d = pi.distance(pj);
|
||
if d < best.0 {
|
||
best = (d, i, j, ei, ej);
|
||
}
|
||
}
|
||
}
|
||
}
|
||
}
|
||
let (d, i, j, ei, ej) = best;
|
||
let mut b = open.remove(j);
|
||
let a = &mut open[i];
|
||
if !ei {
|
||
a.reverse();
|
||
}
|
||
if ej {
|
||
b.reverse();
|
||
}
|
||
if d <= tolerance && !b.anchors.is_empty() {
|
||
let first = b.anchors.remove(0);
|
||
if let Some(l) = a.anchors.last_mut() {
|
||
*l = Anchor::with_handles(l.p, l.h_in, first.h_out);
|
||
}
|
||
} else {
|
||
if let Some(l) = a.anchors.last_mut() {
|
||
l.h_out = l.p;
|
||
}
|
||
if let Some(f) = b.anchors.first_mut() {
|
||
f.h_in = f.p;
|
||
}
|
||
}
|
||
a.anchors.extend(b.anchors);
|
||
}
|
||
closed.extend(open);
|
||
PathData::new(closed)
|
||
}
|
||
|
||
/// Object → Path → Split Into Grid: `rows × cols` rectangles filling `rect` with a gutter between
|
||
/// the rows and one between the columns (row-major, top-left first). No cells when they would have
|
||
/// no size.
|
||
pub fn split_into_grid(rect: Rect, rows: usize, cols: usize, (row_gutter, col_gutter): (f64, f64)) -> Vec<PathData> {
|
||
if rows == 0 || cols == 0 {
|
||
return Vec::new();
|
||
}
|
||
let w = (rect.width() - col_gutter * (cols as f64 - 1.0)) / cols as f64;
|
||
let h = (rect.height() - row_gutter * (rows as f64 - 1.0)) / rows as f64;
|
||
// Written so that a size that is not a number gives no cells either.
|
||
if !(w > 0.0 && h > 0.0 && w.is_finite() && h.is_finite()) {
|
||
return Vec::new();
|
||
}
|
||
let mut out = Vec::with_capacity(rows * cols);
|
||
for r in 0..rows {
|
||
for c in 0..cols {
|
||
let x = rect.x0 + c as f64 * (w + col_gutter);
|
||
let y = rect.y0 + r as f64 * (h + row_gutter);
|
||
out.push(PathData::single(SubPath::polyline(
|
||
&[Point::new(x, y), Point::new(x + w, y), Point::new(x + w, y + h), Point::new(x, y + h)],
|
||
true,
|
||
)));
|
||
}
|
||
}
|
||
out
|
||
}
|
||
|
||
/// The first (`last == false`) or last anchor point of a subpath.
|
||
fn end_point(sp: &SubPath, last: bool) -> Option<Point> {
|
||
if last { sp.anchors.last() } else { sp.anchors.first() }.map(|a| a.p)
|
||
}
|
||
|
||
#[cfg(test)]
|
||
mod tests {
|
||
use super::*;
|
||
|
||
/// The samples Object › Path › Smooth at `level` smooths for `sp`, a subpath with no corner,
|
||
/// and the spread it smooths them with.
|
||
fn smooth_samples(sp: &SubPath, level: f64) -> (Vec<Point>, f64) {
|
||
let opts = smooth_options(&PathData::single(sp.clone()), level);
|
||
let mut pts = Vec::new();
|
||
for (k, s) in subpath_segs(sp).iter().enumerate() {
|
||
sample(&s.c, sample_steps(&s.c, opts.tolerance), &mut pts, k == 0);
|
||
}
|
||
(pts, opts.smooth)
|
||
}
|
||
|
||
/// A traced outline: `n` straight segments around a circle of radius 200, each anchor moved in
|
||
/// or out by up to 0.5 pt.
|
||
fn traced_circle(n: usize) -> SubPath {
|
||
let pts: Vec<Point> = (0..n)
|
||
.map(|i| {
|
||
let a = i as f64 / n as f64 * std::f64::consts::TAU;
|
||
let r = 200.0 + 0.5 * ((i * 7919) % 13) as f64 / 13.0;
|
||
Point::new(300.0 + r * a.cos(), 300.0 + r * a.sin())
|
||
})
|
||
.collect();
|
||
SubPath::polyline(&pts, true)
|
||
}
|
||
|
||
/// [`smooth_points`] weighing every sample on its own.
|
||
fn smooth_points_one_by_one(pts: &[Point], sigma: f64) -> Vec<Point> {
|
||
let mut s = vec![0.0];
|
||
for w in pts.windows(2) {
|
||
s.push(s.last().copied().unwrap_or(0.0) + w[0].distance(w[1]));
|
||
}
|
||
let total = s.last().copied().unwrap_or(0.0);
|
||
pts.iter()
|
||
.zip(&s)
|
||
.map(|(&p, &si)| {
|
||
let reach = (3.0 * sigma).min(si).min(total - si);
|
||
if reach <= 1e-9 {
|
||
return p;
|
||
}
|
||
let spread = reach / 3.0;
|
||
let (mut sum, mut weight) = (Vec2::ZERO, 0.0);
|
||
for (q, &sj) in pts.iter().zip(&s).filter(|(_, sj)| (*sj - si).abs() <= reach) {
|
||
let w = (-(sj - si) * (sj - si) / (2.0 * spread * spread)).exp();
|
||
sum += (*q - p) * w;
|
||
weight += w;
|
||
}
|
||
p + sum / weight
|
||
})
|
||
.collect()
|
||
}
|
||
|
||
/// Next value in 0..1 of a small linear congruential generator.
|
||
fn next(seed: &mut u64) -> f64 {
|
||
*seed = seed.wrapping_mul(6364136223846793005).wrapping_add(1442695040888963407);
|
||
(*seed >> 11) as f64 / (1u64 << 53) as f64
|
||
}
|
||
|
||
#[test]
|
||
fn smoothing_work_per_sample_stays_bounded_on_dense_paths() {
|
||
// Weighing every sample within three spreads took 360 steps per sample for 1,000 anchors and
|
||
// 2,949 for 16,000: the work grew with the square of the anchor count.
|
||
for n in [1_000usize, 16_000] {
|
||
let (pts, sigma) = smooth_samples(&traced_circle(n), 100.0);
|
||
let mut work = 0;
|
||
smooth_points_counted(&pts, sigma, &mut work);
|
||
assert!(work <= 400 * pts.len(), "{n} anchors: {work} steps for {} samples", pts.len());
|
||
}
|
||
// A curve sampled at a tiny tolerance and smoothed far beyond its length.
|
||
let c = CubicBez::new((0.0, 0.0), (0.0, 100.0), (100.0, 100.0), (100.0, 0.0));
|
||
let mut pts = Vec::new();
|
||
sample(&c, sample_steps(&c, 0.00001), &mut pts, true);
|
||
let mut work = 0;
|
||
smooth_points_counted(&pts, 1000.0, &mut work);
|
||
assert!(work <= 400 * pts.len(), "{work} steps for {} samples", pts.len());
|
||
}
|
||
|
||
#[test]
|
||
fn smoothing_points_whose_arc_length_overflows_returns_every_point() {
|
||
let pts: Vec<Point> = (0..40).map(|i| Point::new(if i % 2 == 0 { -1e308 } else { 1e308 }, f64::from(i))).collect();
|
||
assert_eq!(smooth_points(&pts, 10.0).len(), pts.len());
|
||
}
|
||
|
||
#[test]
|
||
fn grouped_smoothing_stays_within_a_thousandth_of_a_spread_of_weighing_one_by_one() {
|
||
let mut seed = 7u64;
|
||
for case in 0..300 {
|
||
let n = 3 + (next(&mut seed) * 2000.0) as usize;
|
||
let mut p = Point::ZERO;
|
||
let mut dir: f64 = 0.0;
|
||
let dense = next(&mut seed) < 0.5;
|
||
let pts: Vec<Point> = (0..n)
|
||
.map(|_| {
|
||
dir += (next(&mut seed) - 0.5) * 1.5;
|
||
let step = if dense { next(&mut seed) * 0.05 } else { next(&mut seed) * 5.0 };
|
||
p += Vec2::new(dir.cos(), dir.sin()) * step;
|
||
p
|
||
})
|
||
.collect();
|
||
let sigma = 0.01 + next(&mut seed) * 50.0;
|
||
let exact = smooth_points_one_by_one(&pts, sigma);
|
||
let grouped = smooth_points(&pts, sigma);
|
||
assert_eq!(grouped.len(), exact.len());
|
||
for (i, (a, b)) in exact.iter().zip(&grouped).enumerate() {
|
||
assert!(a.distance(*b) <= 1e-3 * sigma, "case {case}, point {i}: {a:?} and {b:?}, spread {sigma}");
|
||
}
|
||
assert_eq!((grouped.first(), grouped.last()), (pts.first(), pts.last()), "case {case}");
|
||
}
|
||
}
|
||
}
|