Merge pull request #4396 from dotCooCoo/fix/trace-library-fills-link-swatches

Image Trace: Document Library fills link to the document's global swatches

crates/engine/src/cmd/buildcmds/trace.rs

@@ -1,3 +1,5 @@
+use vectorcraft_color::Swatch;
+
 use super::{
     Appearance, AppearanceItem, Arc, Beside, Color, Document, EngineError, LineCap, LineJoin, LiveShape, Node, NodeId, NodeKind, Paint, Point,
     Result, Session, StrokeLayer, TRACE_NAME, TraceView, Value, bad, fill_only, ids_json, json, root_ids, shape_node, str_param, switch_or, tr,
@@ -58,41 +60,59 @@ fn trace_params(c: &str, p: &Value) -> Result<tr::TraceParams> {
     Ok(params)
 }
 
+/// Document swatch `w`'s solid color with the paint a trace fills with it: a global or spot color,
+/// or a tint of one, linked to its swatch as `swatch_solid` (paint.rs) links it; any other color
+/// unlinked. The color is the one the paint shows (a Lab spot color's CMYK equivalent when the Spot
+/// Colors options use CMYK values).
+fn trace_swatch_paint(d: &Document, w: &Swatch) -> Option<(Color, Paint)> {
+    let linked = d.swatch_link(&w.name).and_then(|(base, tint)| d.tint_paint(&base, tint));
+    let color = linked.as_ref().and_then(Paint::color).or_else(|| w.paint.color())?;
+    Some((color, linked.unwrap_or_else(|| Paint::solid(color))))
+}
+
 /// Document Library with `colorGroup`: the solid colors of the active document's color group
-/// `name` (so named exactly, else ignoring case). Errors name command `c`.
-/// ([`trace_params`] has checked that the library is the document's swatches.)
-fn trace_group_colors(c: &str, s: &Session, name: &str) -> Result<Vec<Color>> {
-    let groups = &s.doc()?.doc.swatch_groups;
+/// `name` (so named exactly, else ignoring case), each with its paint ([`trace_swatch_paint`]).
+/// Errors name command `c`. ([`trace_params`] has checked that the library is the document's
+/// swatches.)
+fn trace_group_colors(c: &str, s: &Session, name: &str) -> Result<Vec<(Color, Paint)>> {
+    let d = &s.doc()?.doc;
+    let groups = &d.swatch_groups;
     let lower = name.to_lowercase();
     let group = groups
         .iter()
         .find(|g| g.name == name)
         .or_else(|| groups.iter().find(|g| g.name.to_lowercase() == lower))
         .ok_or_else(|| bad(c, format!("no color group `{name}` in the document (see swatch.list)")))?;
-    Ok(group.swatches.iter().filter_map(|w| w.paint.color()).collect())
+    Ok(group.swatches.iter().filter_map(|w| trace_swatch_paint(d, w)).collect())
 }
 
 /// Document Library in Color mode: look the library's colors (or its color group's) up into
-/// `params.swatches` → each one as traced (sRGB) with the color to fill with. Errors name command `c`.
-fn trace_library(c: &str, s: &Session, params: &mut tr::TraceParams) -> Result<Vec<([u8; 3], Color)>> {
+/// `params.swatches` → each one as traced (sRGB) with the paint to fill with. The document's
+/// global and spot colors fill linked to their swatches ([`trace_swatch_paint`]); a swatch
+/// library's colors fill unlinked. Errors name command `c`.
+fn trace_library(c: &str, s: &Session, params: &mut tr::TraceParams) -> Result<Vec<([u8; 3], Paint)>> {
     if params.mode != tr::Mode::Color || params.palette != tr::Palette::DocumentLibrary {
         return Ok(vec![]);
     }
     let group = params.color_group.as_deref().filter(|g| !g.is_empty());
     let key = group.unwrap_or(params.library.as_str());
-    let colors = match group {
+    let missing = || bad(c, format!("no swatch library `{key}` (see swatch.library.list; \"document\": the document's swatches)"));
+    let colors: Vec<(Color, Paint)> = match group {
         Some(name) => trace_group_colors(c, s, name)?,
-        None => crate::cmd::swatchlib::library_colors(s, key)
-            .ok_or_else(|| bad(c, format!("no swatch library `{key}` (see swatch.library.list; \"document\": the document's swatches)")))?,
+        None if key == crate::cmd::swatchlib::DOCUMENT_SWATCHES => {
+            let d = &s.active().ok_or_else(missing)?.doc;
+            d.swatches_iter().filter_map(|w| trace_swatch_paint(d, w)).collect()
+        }
+        None => crate::cmd::swatchlib::library_colors(s, key).ok_or_else(missing)?.into_iter().map(|c| (c, Paint::solid(c))).collect(),
     };
     if colors.is_empty() {
         return Err(bad(c, format!("`{key}` has no colours")));
     }
-    let library: Vec<([u8; 3], Color)> = colors
+    let library: Vec<([u8; 3], Paint)> = colors
         .into_iter()
-        .map(|c| {
+        .map(|(c, paint)| {
             let [r, g, b, _] = c.to_rgba8(1.0);
-            ([r, g, b], c)
+            ([r, g, b], paint)
         })
         .collect();
     params.swatches = library.iter().map(|l| l.0).collect();
@@ -260,10 +280,14 @@ pub(super) fn trace_make(s: &mut Session, p: &Value, expand: bool) -> Result<Val
                 *path = shape.to_path();
                 *live = Some(Box::new(shape));
             }
-            // A library colour fills with the swatch's own colour (its model kept).
-            let color = library.iter().find(|(rgb, _)| *rgb == tp.color).map_or_else(|| Color::rgb8(tp.color[0], tp.color[1], tp.color[2]), |l| l.1);
+            // A library color fills with the swatch's own color (its model kept), linked to a
+            // global or spot swatch of the document.
+            let solid = library
+                .iter()
+                .find(|(rgb, _)| *rgb == tp.color)
+                .map_or_else(|| Paint::solid(Color::rgb8(tp.color[0], tp.color[1], tp.color[2])), |l| l.1.clone());
             // Gradients: a path the tracer found to be a linear gradient is filled with it.
-            let paint = tp.gradient.as_ref().map_or_else(|| Paint::solid(color), |g| traced_gradient(g, xf));
+            let paint = tp.gradient.as_ref().map_or(solid, |g| traced_gradient(g, xf));
             n.appearance = match tp.stroke {
                 // Traced lines: round corners, and ends round or square as the tracer found them.
                 Some(width) => Appearance {

crates/engine/src/tests/build.rs

@@ -3047,6 +3047,124 @@ fn image_trace_document_library_uses_a_color_group() {
     trace(&mut s, json!({"mode": "grayscale", "colorGroup": ""})).unwrap();
 }
 
+#[test]
+fn image_trace_document_library_links_fills_to_global_swatches() {
+    let mut s = session();
+    // A global color, a tint of another global color and a process color.
+    s.execute("swatch.new", &json!({"name": "Ink", "color": "#c82828", "global": true})).unwrap();
+    s.execute("swatch.new", &json!({"name": "Sky", "color": "#2846c8", "global": true})).unwrap();
+    s.execute("swatch.new", &json!({"swatch": "Sky", "tint": 50})).unwrap();
+    s.execute("swatch.new", &json!({"name": "Leaf", "color": "#28a03c"})).unwrap();
+    let hex_of = |s: &mut Session, name: &str| {
+        let list = s.execute("swatch.list", &json!({})).unwrap();
+        list["swatches"].as_array().unwrap().iter().find(|w| w["name"] == name).unwrap()["hex"].as_str().unwrap().to_lowercase()
+    };
+    let tint = hex_of(&mut s, "Sky 50%");
+    let [tr, tg, tb] = [1, 3, 5].map(|i| u8::from_str_radix(&tint[i..i + 2], 16).unwrap());
+    let r = vectorcraft_trace::Raster::from_fn(60, 60, |x, y| match (x < 30, y < 30) {
+        (true, _) => [200, 40, 40, 255],
+        (false, true) => [40, 160, 60, 255],
+        (false, false) => [tr, tg, tb, 255],
+    });
+    let img = add_image(&mut s, &r, Affine::IDENTITY);
+    let params = json!({"mode": "color", "palette": "documentLibrary", "library": "document", "colors": 3});
+    // Each fill as (its color, the swatch it links to, its tint), one per color.
+    let fills = |s: &Session, id: &Value| {
+        let mut v: Vec<(String, Option<String>, f32)> = node(s, NodeId(id.as_u64().unwrap()))
+            .children()
+            .unwrap()
+            .iter()
+            .filter_map(|n| match n.appearance.fill_paint() {
+                Paint::Solid { color, swatch, tint } => {
+                    let [r, g, b, _] = color.to_rgba8(1.0);
+                    Some((format!("#{r:02x}{g:02x}{b:02x}"), swatch, tint))
+                }
+                _ => None,
+            })
+            .collect();
+        v.sort_by(|a, b| a.0.cmp(&b.0));
+        v.dedup();
+        v
+    };
+    let fill = |hex: &str, swatch: Option<&str>, tint: f32| (hex.to_string(), swatch.map(String::from), tint);
+    let res = s.execute("imageTrace.makeAndExpand", &json!({"params": params})).unwrap();
+    let got = fills(&s, &res["id"]);
+    assert_eq!(got.len(), 3, "{got:?}");
+    assert!(got.contains(&fill("#c82828", Some("Ink"), 1.0)), "{got:?}");
+    assert!(got.contains(&fill(&tint, Some("Sky"), 0.5)), "{got:?}");
+    assert!(got.contains(&fill("#28a03c", None, 1.0)), "{got:?}");
+    // Editing the global swatches recolors the trace: the tint at its own tint.
+    s.execute("swatch.edit", &json!({"name": "Ink", "color": "#ff8800"})).unwrap();
+    s.execute("swatch.edit", &json!({"name": "Sky", "color": "#000000"})).unwrap();
+    let tint = hex_of(&mut s, "Sky 50%");
+    let got = fills(&s, &res["id"]);
+    assert!(got.contains(&fill("#ff8800", Some("Ink"), 1.0)), "{got:?}");
+    assert!(got.contains(&fill(&tint, Some("Sky"), 0.5)), "{got:?}");
+    assert!(got.contains(&fill("#28a03c", None, 1.0)), "{got:?}");
+    for _ in 0..3 {
+        s.execute("edit.undo", &json!({})).unwrap();
+    }
+    // A color group's global swatches link too.
+    s.execute("swatch.newGroup", &json!({"name": "Brand", "swatches": ["Ink", "Leaf"]})).unwrap();
+    let mut group = params.clone();
+    group["colorGroup"] = json!("Brand");
+    let res = s.execute("imageTrace.makeAndExpand", &json!({"id": img.0, "params": group})).unwrap();
+    let got = fills(&s, &res["id"]);
+    assert!(got.contains(&fill("#c82828", Some("Ink"), 1.0)) && got.contains(&fill("#28a03c", None, 1.0)), "{got:?}");
+    s.execute("edit.undo", &json!({})).unwrap();
+    // A swatch library's colors stay unlinked.
+    let mut web = params.clone();
+    web["library"] = json!("web-safe-216");
+    let res = s.execute("imageTrace.makeAndExpand", &json!({"id": img.0, "params": web})).unwrap();
+    let got = fills(&s, &res["id"]);
+    assert!(!got.is_empty() && got.iter().all(|f| f.1.is_none()), "{got:?}");
+}
+
+#[test]
+fn image_trace_document_library_matches_a_lab_spot_by_its_cmyk_equivalent() {
+    let _g = crate::tests_colormgmt::GLOBAL.lock().unwrap_or_else(|e| e.into_inner());
+    let mut s = session();
+    // A Lab color outside the CMYK gamut, whose CMYK equivalent shows another color.
+    let rgb = |c: Color| {
+        let [r, g, b, _] = c.to_rgba8(1.0);
+        [r, g, b]
+    };
+    let cms = vectorcraft_color::cms::active();
+    let off = |lab: Color| {
+        let cmyk = cms.convert(&lab, vectorcraft_color::cms::Model::Cmyk, cms.settings().intent);
+        rgb(lab).iter().zip(rgb(cmyk)).map(|(a, b)| u32::from(a.abs_diff(b))).sum::<u32>()
+    };
+    let lab = [(30.0, 60.0, -100.0), (60.0, -80.0, 60.0), (55.0, 60.0, 40.0), (90.0, -40.0, 100.0)]
+        .map(|(l, a, b)| Color::Lab { l, a, b })
+        .into_iter()
+        .max_by_key(|c| off(*c))
+        .unwrap();
+    assert!(off(lab) >= 30, "{lab:?} is off by {}", off(lab));
+    let Color::Lab { l, a, b } = lab else { panic!("{lab:?}") };
+    // A spot color of it shown by its CMYK equivalent (Spot Colors options with CMYK values).
+    s.execute("swatch.new", &json!({"name": "Lab Ink", "color": {"l": l, "a": a, "b": b}, "spot": true})).unwrap();
+    s.execute("swatch.spotOptions", &json!({"useLab": false})).unwrap();
+    let shown = s.doc().unwrap().doc.global_color("Lab Ink").unwrap();
+    let [kr, kg, kb] = rgb(shown);
+    let [lr, lg, lb] = rgb(lab);
+    // A process color between the two, nearer the color the spot shows.
+    let near = |k: u8, l: u8| (f32::from(k) + (f32::from(l) - f32::from(k)) * 0.3).round() as u8;
+    let [pr, pg, pb] = [near(kr, lr), near(kg, lg), near(kb, lb)];
+    s.execute("swatch.new", &json!({"name": "Near", "color": format!("#{pr:02x}{pg:02x}{pb:02x}")})).unwrap();
+    let process = Color::rgb8(pr, pg, pb);
+    s.execute("swatch.new", &json!({"name": "Leaf", "color": "#28a03c"})).unwrap();
+    // Art in the color the spot shows traces to the spot.
+    let r = vectorcraft_trace::Raster::from_fn(60, 60, |x, _| if x < 30 { [kr, kg, kb, 255] } else { [40, 160, 60, 255] });
+    add_image(&mut s, &r, Affine::IDENTITY);
+    let params = json!({"mode": "color", "palette": "documentLibrary", "library": "document", "colors": 3});
+    let res = s.execute("imageTrace.makeAndExpand", &json!({"params": params})).unwrap();
+    let g = node(&s, NodeId(res["id"].as_u64().unwrap()));
+    let got: Vec<Paint> = g.children().unwrap().iter().map(|n| n.appearance.fill_paint()).collect();
+    let spot = Paint::Solid { color: shown, swatch: Some("Lab Ink".into()), tint: 1.0 };
+    assert!(got.contains(&spot), "{got:?}");
+    assert!(!got.iter().any(|p| p.color() == Some(process)), "{got:?}");
+}
+
 #[test]
 fn image_trace_create_strokes_makes_stroked_centre_lines() {
     let mut s = session();

docs/image-trace-adjustments.md

@@ -46,6 +46,11 @@ most `colors` of its colors are used. A missing group and a group with no solid
 mode, palette or library in the panel clears the group. A group the active document does not have shows as All
 and traces as All.
 
+**Document Library linked colors.** With Library › Document Swatches, with or without a color group,
+a traced fill or stroke whose color comes from a global or spot swatch is linked to that swatch, and
+one whose color comes from a tint swatch is linked to its base at the tint. Editing the swatch
+recolors the trace. Colors from process swatches and from swatch libraries are not linked.
+
 **Document Library** traces with the library's colors as they are. Each pixel takes the library
 color nearest to it in lightness and hue, with a difference in hue or chroma counted three times
 as much as one in lightness, so a gray or a muted brown takes a black, white or other neutral

docs/target-app-parity.md

@@ -835,6 +835,7 @@ Moved from the ROADMAP's "Shipped so far" on 2026-10-10. Update it when a featur
   Disable, Enable, Unlink and Link Opacity Mask and Opacity Mask Options (`transparency.setOpacityMask`) record no undo step when every mask they act on already has the flags they set.
 - **Image Trace, thin closed outlines:** generated `fit::snap_area_tests` verify nonzero interiors after straightening, opposite closed-boundary winding and Noise controls; see [quality notes](image-trace-quality.md#thin-closed-outlines-with-snap-curves-to-lines). Scores and hours unchanged; open-piece fitting is unchanged.
 - **Image Trace, Document Library color groups:** with Document Swatches, the panel's Colors menu and `"colorGroup"` trace with one color group's colors instead of every swatch, as the public panel documentation describes Document Library; code-drawn tests in `crates/engine` and the panel.
+- **Image Trace, Document Library linked colors:** with Document Swatches, traced fills and strokes from global and spot swatches (and tints of them) are linked to their swatches, so editing a swatch recolors the trace; process colors and swatch-library colors stay unlinked; a code-drawn test in `crates/engine`.
 - **Image Trace, flattened slivers:** in a Color, Grayscale or Black and White trace with Fills, a traced region whose outline straightens onto one line (a single pixel, or a one-pixel row along an edge, its pieces shared with the regions beside it) is left out instead of becoming a selectable path with no area, which paints nothing. Snap Curves To Lines straightens more outlines, so it leaves out more of these. Without Fills, the region's 1 px stroke draws it, and it is kept. Code-drawn tests in `crates/trace`.
 - **Image Trace, Auto Color rare colours:** the Automatic palette keeps colours too rare for its area count when they are distinct (Oklab) and drawn as coherent regions, at most six, protected from mixed-colour merging and Noise; code-drawn stem, highlight, low-contrast and scattered-noise tests (see [quality notes](image-trace-quality.md#auto-color-keeps-rare-colours)).
 - **Image Trace, Document Library keeps neutral tones neutral:** each pixel takes the library color nearest in Oklab with differences in hue and chroma counted three times, so a gray or a muted brown traces as a neutral library color instead of a saturated one of similar lightness; a code-drawn test of gray and brown patches with a black, light and blue library in `crates/trace`.