WIP, not gated: gradients grown over noise and soft rims, largest area first; radial gradients (truth input, engine mapping)

crates/engine/src/cmd/buildcmds.rs

@@ -120,7 +120,7 @@ pub fn specs() -> Vec<CommandSpec> {
             "Make",
             ["Object", "Image Trace"],
             None,
-            "{id?: image or Image Trace group (default: selection), preset?: name (imageTrace.presets), enhanced?: false (the preset's enhanced version: with Auto Grouping, and with Shapes in all but High Fidelity Photo and Flat Logo), params?: {mode: \"blackAndWhite\"|\"grayscale\"|\"color\"|\"logo\", threshold: 0-255, palette: \"limited\"|\"fullTone\"|\"automatic\"|\"documentLibrary\" (color mode; limited: the `colors` best colours, fullTone: as many as the tones need, more with colorDetail, automatic: flat art with its own colours, else fullTone, documentLibrary: at most `colors` of the library's colours, as they are), colors: 2-256, colorDetail: 0-100 (fullTone, automatic), library: \"document\" (the document's swatches) or a swatch library id or name (swatch.library.list; documentLibrary), paths: 0-100, corners: 0-100, noise: px, method: \"abutting\"|\"overlapping\", ignoreWhite (leave out white areas), ignoreColor?: \"#rrggbb\" (with ignoreWhite: the colour left out instead of white), snapCurvesToLines, shapes: false (filled outlines that are a circle, an ellipse, a rectangle or a regular polygon come out as that live shape), autoGrouping: false (each path that has others inside it is grouped with them), gradients: false (grayscale and color: an area whose colour changes evenly along one direction is one path with a linear gradient fill), fills: true, strokes: false (Create: lines up to strokeWidth wide become stroked centre lines; without fills, wider areas become stroked outlines), strokeWidth: px (10), logoColors?: [\"#rrggbb\"…] (mode logo: flat-colour logos only; colours found automatically or named here, white is always its own colour, at most ten; noise = areas under noise/10 px ignored; edges to a fraction of a pixel, sharp corners restored, lines and circles snapped; enclosed transparent areas are painted white unless ignoreWhite makes them holes; fills/strokes are ignored; gradients and photos are refused)}, view?: as imageTrace.setView (default: the traced object's own, else tracingResult), ids?: [id…] (instead of id)} → {id, paths, anchors, colors}",
+            "{id?: image or Image Trace group (default: selection), preset?: name (imageTrace.presets), enhanced?: false (the preset's enhanced version: with Auto Grouping, and with Shapes in all but High Fidelity Photo and Flat Logo), params?: {mode: \"blackAndWhite\"|\"grayscale\"|\"color\"|\"logo\", threshold: 0-255, palette: \"limited\"|\"fullTone\"|\"automatic\"|\"documentLibrary\" (color mode; limited: the `colors` best colours, fullTone: as many as the tones need, more with colorDetail, automatic: flat art with its own colours, else fullTone, documentLibrary: at most `colors` of the library's colours, as they are), colors: 2-256, colorDetail: 0-100 (fullTone, automatic), library: \"document\" (the document's swatches) or a swatch library id or name (swatch.library.list; documentLibrary), paths: 0-100, corners: 0-100, noise: px, method: \"abutting\"|\"overlapping\", ignoreWhite (leave out white areas), ignoreColor?: \"#rrggbb\" (with ignoreWhite: the colour left out instead of white), snapCurvesToLines, shapes: false (filled outlines that are a circle, an ellipse, a rectangle or a regular polygon come out as that live shape), autoGrouping: false (each path that has others inside it is grouped with them), gradients: false (grayscale and color: an area whose colour changes evenly along one direction, or outwards from a point, is one path with a linear or radial gradient fill), fills: true, strokes: false (Create: lines up to strokeWidth wide become stroked centre lines; without fills, wider areas become stroked outlines), strokeWidth: px (10), logoColors?: [\"#rrggbb\"…] (mode logo: flat-colour logos only; colours found automatically or named here, white is always its own colour, at most ten; noise = areas under noise/10 px ignored; edges to a fraction of a pixel, sharp corners restored, lines and circles snapped; enclosed transparent areas are painted white unless ignoreWhite makes them holes; fills/strokes are ignored; gradients and photos are refused)}, view?: as imageTrace.setView (default: the traced object's own, else tracingResult), ids?: [id…] (instead of id)} → {id, paths, anchors, colors}",
             has_selection_or_ids,
             |s, p| trace_make(s, p, false)
         ),
@@ -729,12 +729,14 @@ fn traced_shape(shape: tr::TracedShape, xf: vectorcraft_geom::Affine) -> LiveSha
     live
 }
 
-/// The gradient fill for a linear gradient the tracer found (in the image's pixels), placed in the
-/// document by `xf`.
+/// The gradient fill for a gradient the tracer found (in the image's pixels), placed in the
+/// document by `xf` (a radial one: its middle and a point on its outermost circle; a circle
+/// still where the image is scaled evenly).
 fn traced_gradient(g: &tr::TracedGradient, xf: vectorcraft_geom::Affine) -> Paint {
     use vectorcraft_color::{Gradient, GradientGeom, GradientKind, GradientPaint, GradientStop};
     let stops = g.stops.iter().map(|&(at, c)| GradientStop::new(at as f32, Color::rgb8(c[0], c[1], c[2]))).collect();
-    let mut paint = GradientPaint::new(Gradient { kind: GradientKind::Linear, stops });
+    let kind = if g.radial { GradientKind::Radial } else { GradientKind::Linear };
+    let mut paint = GradientPaint::new(Gradient { kind, stops });
     paint.geom = Some(GradientGeom { start: xf * g.start, end: xf * g.end, aspect: 1.0, focal: None });
     Paint::Gradient(Box::new(paint))
 }

crates/engine/src/tests_build.rs

@@ -771,6 +771,19 @@ fn image_trace_gradients_fills_with_a_gradient() {
     assert!((a.x - 50.0).abs() < 3.0 && (b.x - 250.0).abs() < 3.0 && (a.y - b.y).abs() < 2.0, "{geom:?}");
     let flat = make(false);
     assert!(flat.len() > 1 && flat.iter().all(|n| matches!(n.appearance.fill_paint(), Paint::Solid { .. })));
+    // Colours going out from a point: a radial gradient, its middle where the image has it.
+    let round = vectorcraft_trace::Raster::from_fn(120, 100, |x, y| {
+        let t = ((f64::from(x) + 0.5 - 50.0).hypot(f64::from(y) + 0.5 - 40.0) / 90.0).min(1.0);
+        [(250.0 - 200.0 * t) as u8, (230.0 - 150.0 * t) as u8, 90, 255]
+    });
+    let mut s = session();
+    add_image(&mut s, &round, Affine::translate((10.0, 20.0)));
+    let r = s.execute("imageTrace.make", &json!({"preset": "6 Colors", "params": {"gradients": true}})).unwrap();
+    let paths = traced_paths(&node(&s, NodeId(r["id"].as_u64().unwrap())));
+    let Paint::Gradient(g) = paths[0].appearance.fill_paint() else { panic!("{:?}", paths[0].appearance.fill_paint()) };
+    assert_eq!((paths.len(), g.gradient.kind), (1, vectorcraft_color::GradientKind::Radial));
+    let middle = g.geom.as_ref().unwrap().start;
+    assert!((middle.x - 60.0).abs() < 1.5 && (middle.y - 60.0).abs() < 1.5, "{middle:?}");
 }
 
 /// A preset's enhanced version: the preset with Auto Grouping and Shapes, under the preset's name.