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bflatasticandClaude Opus 5.5
d8eff17b9f
Radial gradients show a dashed extent ellipse: its handle across the bar sets the aspect ratio, the ellipse elsewhere rotates it, and the dot inside the centre ring drags the focal point (GradientGeom.focal) for an off-centre radial. paint.setGradientGeom takes aspect (%) and focal ([x,y] | null), and start/end may be left out; the focal point keeps its place in the ellipse as the vector, aspect and object transform. It renders as a two-point radial, exports and imports as SVG fx/fy and PDF two-point radial shadings, expands to off-centre rings, and travels in gradient params and the native format. Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
58 lines
2.6 KiB
Rust
58 lines
2.6 KiB
Rust
//! Radial gradients' focal points as two-point radial shadings, out and back in.
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use vectorcraft_color::{Gradient, GradientGeom, GradientKind, GradientPaint, Paint};
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use vectorcraft_doc::{Appearance, Document, Node};
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use vectorcraft_geom::{Point, Rect, shapes};
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use vectorcraft_testkit::raster::{assert_similar, render_artboard};
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use crate::*;
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/// A page-sized square filled with a radial on `start`→`end` at `aspect`, focal point `focal`.
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fn doc(start: Point, end: Point, aspect: f64, focal: Point) -> Document {
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let mut geom = GradientGeom { start, end, aspect, focal: None };
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geom.set_focal(Some(focal));
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let mut gp = GradientPaint::new(Gradient { kind: GradientKind::Radial, ..Gradient::default() });
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gp.geom = Some(geom);
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let mut d = Document::new(200.0, 200.0);
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let l = d.layers[0].id;
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let id = d.alloc_id();
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let ap = Appearance::basic(Paint::Gradient(Box::new(gp)), Paint::None, 0.0);
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d.insert(Some(l), 0, Node::path(id, shapes::rectangle(Rect::new(0.0, 0.0, 200.0, 200.0)), ap)).unwrap();
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d
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}
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fn geom(d: &Document) -> GradientGeom {
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let mut out = None;
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d.walk(|n| {
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if let Paint::Gradient(g) = n.appearance.fill_paint() {
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out = g.geom;
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}
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});
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out.expect("a gradient fill")
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}
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#[test]
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fn a_focal_point_round_trips_as_a_two_point_radial_shading() {
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for (end, aspect) in [(Point::new(180.0, 100.0), 1.0), (Point::new(100.0, 40.0), 0.5)] {
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let d = doc(Point::new(100.0, 100.0), end, aspect, Point::new(80.0, 110.0));
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let back = import(&export(&d, &PdfOptions::default()).unwrap()).unwrap();
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let g = geom(&back);
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let f = g.focal.expect("focal kept");
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assert!(f.distance(Point::new(80.0, 110.0)) < 0.05 && g.start.distance(Point::new(100.0, 100.0)) < 0.05, "{g:?}");
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// The same ellipse (its axes may come back swapped, with the aspect inverted).
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let want = geom(&d);
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for p in [Point::new(30.0, 100.0), Point::new(100.0, 170.0), Point::new(140.0, 60.0), Point::new(90.0, 125.0)] {
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let (a, b) = (g.param_at(GradientKind::Radial, p), want.param_at(GradientKind::Radial, p));
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assert!((a - b).abs() < 1e-3, "{p:?}: {a} vs {b}: {g:?}");
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}
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// And it looks the same.
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assert_similar(&render_artboard(&back), &render_artboard(&d), 3.0, 0.01);
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}
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}
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#[test]
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fn a_centred_radial_imports_without_a_focal_point() {
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let d = doc(Point::new(100.0, 100.0), Point::new(180.0, 100.0), 1.0, Point::new(100.0, 100.0));
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assert_eq!(geom(&import(&export(&d, &PdfOptions::default()).unwrap()).unwrap()).focal, None);
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}
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