vectorcraft/crates/effects/src/stylize.rs

162 lines
6.1 KiB
Rust

//! Convert to Shape, Round Corners and Scribble.
use serde_json::Value;
use vectorcraft_geom::kurbo;
use vectorcraft_geom::shapes::{self, KAPPA};
use vectorcraft_geom::{Affine, Anchor, PathData, Point, Rect, SubPath};
use crate::util::*;
/// Convert to Shape (rectangle / rounded rectangle / ellipse) around the bounds.
pub fn convert_to_shape(id: &str, b: Rect, p: &Value) -> PathData {
let r = if flag(p, "relative", true) {
let (ew, eh) = (num(p, "extraW", 18.0), num(p, "extraH", 18.0));
let r = b.inflate(ew / 2.0, eh / 2.0);
Rect::new(r.x0.min(b.center().x), r.y0.min(b.center().y), r.x1.max(b.center().x), r.y1.max(b.center().y))
} else {
let (w, h) = (num(p, "width", 100.0).abs(), num(p, "height", 100.0).abs());
Rect::from_center_size(b.center(), (w, h))
};
match id {
"convertToShape.ellipse" => shapes::ellipse(r),
"convertToShape.roundedRectangle" => shapes::rounded_rectangle(r, num(p, "radius", 9.0)),
_ => shapes::rectangle(r),
}
}
/// Round Corners: every sharp, handle-less corner becomes a circular-ish arc of `radius`.
pub fn round_corners(path: &PathData, radius: f64) -> PathData {
if radius <= 0.0 {
return path.clone();
}
let mut subs = vec![];
for sp in &path.subpaths {
let n = sp.anchors.len();
if n < 3 && (n != 2 || sp.closed) {
subs.push(sp.clone());
continue;
}
let mut out: Vec<Anchor> = vec![];
for i in 0..n {
let a = sp.anchors[i];
let interior = sp.closed || (i > 0 && i + 1 < n);
if !interior || a.has_in() || a.has_out() {
out.push(a);
continue;
}
let prev = &sp.anchors[(i + n - 1) % n];
let next = &sp.anchors[(i + 1) % n];
// Tangent directions toward the neighbours (their handles if the segments curve).
let tp = if prev.has_out() { prev.h_out } else { prev.p };
let tn = if next.has_in() { next.h_in } else { next.p };
let (vp, vn) = (tp - a.p, tn - a.p);
let (lp, ln) = (vp.hypot(), vn.hypot());
if lp < 1e-9 || ln < 1e-9 {
out.push(a);
continue;
}
let (up, un) = (vp / lp, vn / ln);
// Nearly straight: nothing to round.
if up.dot(un) < -0.9999 {
out.push(a);
continue;
}
let d = radius.min(prev.p.distance(a.p) / 2.0).min(next.p.distance(a.p) / 2.0);
let pa = a.p + up * d;
let pb = a.p + un * d;
let k = d * KAPPA;
out.push(Anchor::with_handles(pa, pa, pa - up * k));
out.push(Anchor::with_handles(pb, pb - un * k, pb));
}
subs.push(SubPath::new(out, sp.closed));
}
PathData::new(subs)
}
fn flatten(path: &PathData) -> Vec<Vec<Point>> {
let mut polys: Vec<Vec<Point>> = vec![];
kurbo::flatten(path.to_bezpath(), 0.25, |el| match el {
kurbo::PathEl::MoveTo(p) => polys.push(vec![p]),
kurbo::PathEl::LineTo(p) => {
if let Some(l) = polys.last_mut() {
l.push(p)
}
}
kurbo::PathEl::ClosePath => {
if let Some(l) = polys.last_mut()
&& let Some(&f) = l.first()
{
l.push(f)
}
}
_ => {}
});
polys
}
/// Scribble (simplified): a single zig-zag hatching across the filled area at `angle`, outlined
/// to `strokeWidth` so the fill paints it.
pub fn scribble(path: &PathData, b: Rect, p: &Value) -> PathData {
let angle = num(p, "angle", 30.0).to_radians();
let overlap = num(p, "overlap", 0.0);
let width = num(p, "strokeWidth", 3.0).clamp(0.01, 1000.0);
let curvy = num(p, "curviness", 5.0).clamp(0.0, 100.0) / 100.0;
let spacing = num(p, "spacing", 5.0).max(0.1);
let variation = num(p, "variation", 0.5).clamp(0.0, 100.0);
let seed = seed(p);
let c = b.center();
let to_local = Affine::translate(c.to_vec2()) * Affine::rotate(angle) * Affine::translate(-c.to_vec2());
let from_local = to_local.inverse();
let polys: Vec<Vec<Point>> = flatten(path).into_iter().map(|pl| pl.into_iter().map(|q| from_local * q).collect()).collect();
let (mut y0, mut y1) = (f64::INFINITY, f64::NEG_INFINITY);
for q in polys.iter().flatten() {
y0 = y0.min(q.y);
y1 = y1.max(q.y);
}
if !y0.is_finite() || y1 - y0 < 1e-9 {
return PathData::default();
}
let step = spacing.max((y1 - y0) / 2000.0);
let mut pts: Vec<Point> = vec![];
let mut y = y0 + step / 2.0;
let mut row = 0u64;
while y < y1 {
let mut xs: Vec<f64> = vec![];
for pl in &polys {
for w in pl.windows(2) {
let (a, bq) = (w[0], w[1]);
if (a.y <= y && bq.y > y) || (bq.y <= y && a.y > y) {
xs.push(a.x + (y - a.y) / (bq.y - a.y) * (bq.x - a.x));
}
}
}
xs.sort_by(f64::total_cmp);
let mut spans: Vec<(f64, f64)> = xs.as_chunks::<2>().0.iter().map(|s| (s[0] - overlap, s[1] + overlap)).collect();
if row % 2 == 1 {
spans.reverse();
}
for (a, bx) in spans {
let jitter = |k: u64| variation * noise(seed, row, k, 3);
let (l, r) = (Point::new(a + jitter(0), y + jitter(1)), Point::new(bx + jitter(2), y + jitter(3)));
if row.is_multiple_of(2) {
pts.push(l);
pts.push(r);
} else {
pts.push(r);
pts.push(l);
}
}
row += 1;
y += step;
}
if pts.len() < 2 {
return PathData::default();
}
let line = if curvy > 0.0 { catmull_rom(&pts, false, curvy * 2.0) } else { SubPath::polyline(&pts, false) };
let mut center = PathData::single(line);
center.transform(to_local);
let stroke = kurbo::Stroke::new(width).with_join(kurbo::Join::Round).with_caps(kurbo::Cap::Round);
let outline = kurbo::stroke(center.to_bezpath(), &stroke, &kurbo::StrokeOpts::default(), 0.05);
PathData::from_bezpath(&outline)
}