Merge pull request #4705 from dotCooCoo/fix/trace-library-global-swatch-same-color

Image Trace: Document Library links to a global swatch that shares a process swatch's color

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

@@ -1,3 +1,5 @@
+use std::collections::HashMap;
+
 use vectorcraft_color::Swatch;
 use vectorcraft_doc::ImageObject;
 
@@ -557,6 +559,16 @@ pub(super) fn trace_make(s: &mut Session, p: &Value, expand: bool) -> Result<Val
     let unit = xf.determinant().abs().sqrt();
     let (npaths, anchors, colors) = (res.paths.len(), res.anchor_count(), res.palette.len());
     let label = if expand { "Image Trace (Make and Expand)" } else { "Image Trace" };
+    // A library color fills with the swatch's own color (its model kept), linked to a
+    // global or spot swatch of the document. Of the swatches that trace as this color,
+    // the first linked one is taken, else the first. Build the lookup once per trace.
+    let mut by_color: HashMap<[u8; 3], &Paint> = HashMap::new();
+    for (rgb, paint) in &library {
+        let chosen = by_color.entry(*rgb).or_insert(paint);
+        if !matches!(**chosen, Paint::Solid { swatch: Some(_), .. }) && matches!(paint, Paint::Solid { swatch: Some(_), .. }) {
+            *chosen = paint;
+        }
+    }
     let id = s.edit(label, |d, sel| {
         let src = d.node(target).cloned().ok_or(EngineError::NoNode(target))?;
         let mut image = if is_trace_group(&src) {
@@ -584,12 +596,8 @@ 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 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());
+            let solid =
+                by_color.get(&tp.color).map_or_else(|| Paint::solid(Color::rgb8(tp.color[0], tp.color[1], tp.color[2])), |paint| (*paint).clone());
             // Gradients: a path the tracer found to be a linear gradient is filled with it.
             let paint = tp.gradient.as_ref().map_or(solid, |g| traced_gradient(g, xf));
             n.appearance = match tp.stroke {

crates/engine/src/tests/build.rs

@@ -3178,6 +3178,43 @@ fn image_trace_document_library_links_fills_to_global_swatches() {
     assert!(!got.is_empty() && got.iter().all(|f| f.1.is_none()), "{got:?}");
 }
 
+#[test]
+fn image_trace_document_library_links_to_a_global_swatch_after_a_process_swatch_of_its_color() {
+    let mut s = session();
+    // A process swatch, then two global swatches, all of one color.
+    s.execute("swatch.new", &json!({"name": "Red", "color": "#c82828"})).unwrap();
+    s.execute("swatch.new", &json!({"name": "Ink", "color": "#c82828", "global": true})).unwrap();
+    s.execute("swatch.new", &json!({"name": "Ink 2", "color": "#c82828", "global": true})).unwrap();
+    s.execute("swatch.new", &json!({"name": "Leaf", "color": "#28a03c"})).unwrap();
+    s.execute("swatch.new", &json!({"name": "Sky", "color": "#2846c8", "global": true})).unwrap();
+    let [tr, tg, tb, _] = s.doc().unwrap().doc.tint_paint("Sky", 0.5).unwrap().color().unwrap().to_rgba8(1.0);
+    let tint_hex = format!("#{tr:02x}{tg:02x}{tb:02x}");
+    s.execute("swatch.new", &json!({"name": "Mist", "color": tint_hex})).unwrap();
+    s.execute("swatch.new", &json!({"swatch": "Sky", "tint": 50})).unwrap();
+    let r = vectorcraft_trace::Raster::from_fn(60, 60, |x, _| match x {
+        0..20 => [200, 40, 40, 255],
+        20..40 => [40, 160, 60, 255],
+        _ => [tr, tg, tb, 255],
+    });
+    add_image(&mut s, &r, Affine::IDENTITY);
+    let params = json!({"mode": "color", "palette": "documentLibrary", "library": "document", "colors": 8});
+    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 red = Color::rgb8(200, 40, 40);
+    let reds: Vec<&Paint> = got.iter().filter(|p| p.color().map(|c| c.to_rgba8(1.0)) == Some(red.to_rgba8(1.0))).collect();
+    assert!(!reds.is_empty(), "{got:?}");
+    assert!(reds.iter().all(|p| matches!(p, Paint::Solid { swatch: Some(w), .. } if w == "Ink")), "{got:?}");
+    let tints: Vec<&Paint> = got.iter().filter(|p| p.color().map(|c| c.to_rgba8(1.0)) == Some([tr, tg, tb, 255])).collect();
+    assert!(!tints.is_empty(), "{got:?}");
+    assert!(tints.iter().all(|p| matches!(p, Paint::Solid { swatch: Some(w), tint, .. } if w == "Sky" && *tint == 0.5)), "{got:?}");
+    // Editing the global swatch recolors the trace.
+    s.execute("swatch.edit", &json!({"name": "Ink", "color": "#ff8800"})).unwrap();
+    let g = node(&s, NodeId(res["id"].as_u64().unwrap()));
+    let orange = Color::rgb8(255, 136, 0).to_rgba8(1.0);
+    assert!(g.children().unwrap().iter().any(|n| n.appearance.fill_paint().color().map(|c| c.to_rgba8(1.0)) == Some(orange)));
+}
+
 #[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());

docs/image-trace-adjustments.md

@@ -49,7 +49,9 @@ 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.
+recolors the trace. Colors from process swatches and from swatch libraries are not linked. When
+several swatches show the same color, the first of them in the list that is a global, spot or tint
+swatch gives the link.
 
 **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