Stroke: keep Overprint (overprint)

Photoshop stores Stroke › Overprint as `overprint` in the FrFX
descriptor. StrokeFx had no field for it, so an edited stroke was
written back without it and a stroke with Overprint on lost it.

Add `StrokeFx::overprint` (serde default, so older .pcraft files load),
read and write `overprint`, accept it in layer.layerStyle.stroke and show
the Overprint checkbox in the Layer Style dialog, as Photoshop does.
Rendering is unchanged.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/compose/examples/bench_tsly_stroke.rs

@@ -26,6 +26,7 @@ fn document_with_strokes(layer_count: usize) -> Result<Document, Box<dyn Error>>
             size: 6.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(Color::rgb(0.8, 0.1, 0.2)),
+            overprint: false,
         }));
         layer.advanced.transparency_shapes = false;
         document.layers.push(layer);

crates/compose/src/advanced_tests.rs

@@ -289,6 +289,7 @@ fn inside_stroke() -> Effect {
         size: 2.0,
         position: StrokePosition::Inside,
         paint: FxPaint::Color(Color::rgb(1.0, 0.0, 0.0)),
+        overprint: false,
     })
 }
 
@@ -298,6 +299,7 @@ fn outside_stroke() -> Effect {
         size: 6.0,
         position: StrokePosition::Outside,
         paint: FxPaint::Color(Color::rgb(1.0, 0.0, 0.0)),
+        overprint: false,
     })
 }
 
@@ -318,6 +320,7 @@ fn shapeless_stroke_tile_skips_match_full_region_across_blending_settings() {
                             size: 6.0,
                             position,
                             paint: FxPaint::Color(Color::rgb(1.0, 0.0, 0.0)),
+                            overprint: false,
                         })];
                         l.blend = blend;
                         l.fill_opacity = fill;

crates/compose/src/stroke_tests.rs

@@ -21,7 +21,7 @@ fn px(doc: &Document, x: i32, y: i32) -> [f32; 4] {
 }
 
 fn stroke(size: f32, position: StrokePosition, paint: FxPaint) -> Effect {
-    Effect::Stroke(StrokeFx { common: FxCommon::new(BlendMode::Normal, 1.0), size, position, paint })
+    Effect::Stroke(StrokeFx { common: FxCommon::new(BlendMode::Normal, 1.0), size, position, paint, overprint: false })
 }
 
 fn blue() -> FxPaint {

crates/compose/src/tests.rs

@@ -874,6 +874,7 @@ fn stroke(size: f32, position: StrokePosition) -> Effect {
         size,
         position,
         paint: FxPaint::Color(Color::rgb(0.0, 0.0, 1.0)),
+        overprint: false,
     })
 }
 
@@ -1587,6 +1588,7 @@ fn upper_stroke_blends_with_the_backdrop_not_the_lower_stroke() {
         size: 3.0,
         position: StrokePosition::Outside,
         paint: FxPaint::Color(Color::rgb(1.0, 1.0, 0.0)),
+        overprint: false,
     });
     let d = fx_doc(vec![yellow, stroke(8.0, StrokePosition::Outside)]);
     assert!(close4(px(&d, 8, 20), [1.0, 1.0, 0.0, 1.0]), "{:?}", px(&d, 8, 20));
@@ -2517,6 +2519,7 @@ fn nested_parallel_fx_doc() -> Document {
         size: 3.0,
         position: StrokePosition::Inside,
         paint: FxPaint::Color(Color::rgb(1.0, 0.0, 0.0)),
+        overprint: false,
     })];
     let mut glow = Layer::new("glow", LayerContent::Fill(g(90.0)));
     glow.opacity = 0.5;

crates/doc/src/effects.rs

@@ -166,6 +166,9 @@ pub struct StrokeFx {
     pub size: f32,
     pub position: StrokePosition,
     pub paint: FxPaint,
+    /// Overprint (PSD `overprint`).
+    #[serde(default)]
+    pub overprint: bool,
 }
 
 #[derive(Clone, Debug, PartialEq, Serialize, Deserialize)]

crates/engine/src/layer_style.rs

@@ -91,7 +91,7 @@ pub fn effect_defaults(kind: &str) -> Value {
         "innerGlow" => {
             json!({"blend": "Screen", "opacity": 75, "color": "#ffffbe", "source": "edge", "choke": 0, "size": 5, "contour": "Linear", "antiAlias": false, "noise": 0})
         }
-        "stroke" => json!({"size": 3, "position": "outside", "blend": "Normal", "opacity": 100, "color": "#000000"}),
+        "stroke" => json!({"size": 3, "position": "outside", "blend": "Normal", "opacity": 100, "overprint": false, "color": "#000000"}),
         "colorOverlay" => json!({"blend": "Normal", "color": "#ff0000", "opacity": 100}),
         "gradientOverlay" => {
             json!({"blend": "Normal", "opacity": 100, "from": "#000000", "to": "#ffffff", "reverse": false, "style": "linear", "angle": 90, "scale": 100})
@@ -510,6 +510,7 @@ fn fresh_effect(kind: &str) -> Option<Effect> {
             size: 3.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(Color::rgb(1.0, 0.0, 0.0)),
+            overprint: false,
         }),
         "colorOverlay" => Effect::ColorOverlay { common: FxCommon::new(BlendMode::Normal, 1.0), color: Color::rgb(1.0, 0.0, 0.0) },
         "gradientOverlay" => Effect::GradientOverlay { common: FxCommon::new(BlendMode::Normal, 1.0), gradient: Gradient::default(), dither: false },
@@ -690,6 +691,7 @@ pub fn overlay_effect(fx: &mut Effect, p: &Value) {
                     _ => StrokePosition::Outside,
                 };
             }
+            set_bool(p, "overprint", &mut s.overprint);
             if p.get("from").is_some() {
                 s.paint = FxPaint::Gradient(gradient(p));
             } else if let Some(c) = color_of(p, "color") {
@@ -1005,7 +1007,7 @@ pub fn specs() -> Vec<CommandSpec> {
         style_cmd!(
             "stroke",
             "Stroke…",
-            r##"{"size":px=3,"position":"outside|inside|center","color":"#rrggbb","from":"#rrggbb","to":"#rrggbb","method":"classic|perceptual|linear|smooth"?,"smoothness":0..100=100,"style":str,"angle":deg,"opacity":0..100,"blend":str,"add":bool}"##
+            r##"{"size":px=3,"position":"outside|inside|center","color":"#rrggbb","from":"#rrggbb","to":"#rrggbb","method":"classic|perceptual|linear|smooth"?,"smoothness":0..100=100,"style":str,"angle":deg,"opacity":0..100,"blend":str,"overprint":bool,"add":bool}"##
         ),
         style_cmd!("colorOverlay", "Color Overlay…", r##"{"color":"#rrggbb","opacity":0..100=100,"blend":str,"add":bool}"##),
         style_cmd!(
@@ -1137,6 +1139,17 @@ mod tests {
         assert_eq!((t.name.as_str(), t.depth, t.invert), ("Bubbles", -2.0, true));
     }
 
+    #[test]
+    fn stroke_overprint_is_a_param() {
+        let mut s = session();
+        s.execute("layer.layerStyle.stroke", json!({"size": 4, "overprint": true})).unwrap();
+        let Effect::Stroke(st) = &effects(&s)[0] else { panic!() };
+        assert!(st.overprint);
+        s.execute("layer.layerStyle.stroke", json!({"overprint": false})).unwrap();
+        let Effect::Stroke(st) = &effects(&s)[0] else { panic!() };
+        assert!(!st.overprint);
+    }
+
     #[test]
     fn every_style_command_adds_its_effect() {
         for kind in ["dropShadow", "innerShadow", "outerGlow", "innerGlow", "stroke", "colorOverlay", "gradientOverlay", "bevelEmboss", "satin"] {
@@ -1313,6 +1326,7 @@ mod tests {
             size: 7.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Gradient(Gradient { stops: vec![(0.0, Color::rgb(0.0, 0.0, 1.0)), (1.0, Color::WHITE)], ..Gradient::default() }),
+            overprint: false,
         });
         let r = s
             .execute(
@@ -1349,6 +1363,7 @@ mod tests {
             size: 3.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(Color::BLACK),
+            overprint: false,
         });
         for p in [
             json!({}),

crates/gpu/src/fx.rs

@@ -852,8 +852,9 @@ mod tests {
         use photocraft_color::{BlendMode, Color};
         use photocraft_doc::{FxCommon, FxPaint, StrokeFx, StrokePosition};
         let light = GlobalLight::default();
-        let stroke =
-            |size, position| Effect::Stroke(StrokeFx { common: FxCommon::new(BlendMode::Normal, 1.0), size, position, paint: FxPaint::Color(Color::BLACK) });
+        let stroke = |size, position| {
+            Effect::Stroke(StrokeFx { common: FxCommon::new(BlendMode::Normal, 1.0), size, position, paint: FxPaint::Color(Color::BLACK), overprint: false })
+        };
         // Narrow (< STROKE_CHAMFER_MAX): the chamfer, exactly as before #3646.
         let narrow = program(&stroke(6.0, StrokePosition::Outside), &light, false);
         assert!(narrow.fields.iter().any(|(k, _)| *k == FieldKind::StrokeOutside), "a narrow raster outside stroke keeps the chamfer: {:?}", narrow.fields);

crates/gpu/tests/parity.rs

@@ -855,7 +855,13 @@ fn hard_stop_effects_and_gradient_maps_request_cpu() {
             let paint = FxPaint::Gradient(gradient.clone());
             let effects = [
                 Effect::GradientOverlay { common: FxCommon::new(BlendMode::Normal, 1.0), gradient, dither: false },
-                Effect::Stroke(StrokeFx { common: FxCommon::new(BlendMode::Normal, 1.0), size: 1.0, position: StrokePosition::Inside, paint: paint.clone() }),
+                Effect::Stroke(StrokeFx {
+                    common: FxCommon::new(BlendMode::Normal, 1.0),
+                    size: 1.0,
+                    position: StrokePosition::Inside,
+                    paint: paint.clone(),
+                    overprint: false,
+                }),
                 Effect::InnerGlow(glow(paint.clone(), GlowTechnique::Softer, 1.0, 0.0, GlowSource::Edge)),
                 Effect::OuterGlow(glow(paint, GlowTechnique::Softer, 1.0, 0.0, GlowSource::Edge)),
             ];
@@ -1340,7 +1346,7 @@ fn bevel(style: BevelStyle, up: bool, size: f32, soften: f32) -> Bevel {
 }
 
 fn stroke(size: f32, position: StrokePosition, paint: FxPaint) -> StrokeFx {
-    StrokeFx { common: FxCommon::new(BlendMode::Normal, 0.9), size, position, paint }
+    StrokeFx { common: FxCommon::new(BlendMode::Normal, 0.9), size, position, paint, overprint: false }
 }
 
 fn checker_pattern() -> Pattern {

crates/io/src/effects_map.rs

@@ -213,6 +213,7 @@ fn parse_stroke(d: &Descriptor) -> StrokeFx {
             _ => StrokePosition::Outside,
         },
         paint,
+        overprint: bool_of(d, "overprint"),
     }
 }
 
@@ -404,7 +405,8 @@ fn write_one(e: &Effect) -> (&'static str, Descriptor) {
             };
             let mut d = with_common(Descriptor::new("FrFX"), &s.common)
                 .with("Styl", Value::Enumerated { type_id: Id::new("FStl"), value: Id::new(styl) })
-                .with("Sz  ", unit(b"#Pxl", s.size));
+                .with("Sz  ", unit(b"#Pxl", s.size))
+                .with("overprint", Value::Boolean(s.overprint));
             d = match &s.paint {
                 FxPaint::Color(c) => {
                     d.with("PntT", Value::Enumerated { type_id: Id::new("FrFl"), value: Id::new("SClr") }).with("Clr ", Value::Descriptor(color_to_desc(c)))
@@ -680,12 +682,14 @@ mod tests {
                 size: 3.0,
                 position: StrokePosition::Inside,
                 paint: FxPaint::Color(Color::rgb(0.0, 1.0, 0.0)),
+                overprint: false,
             }),
             Effect::Stroke(StrokeFx {
                 common: FxCommon::new(BlendMode::Multiply, 0.5),
                 size: 6.0,
                 position: StrokePosition::Center,
                 paint: FxPaint::Gradient(g.clone()),
+                overprint: true,
             }),
             Effect::ColorOverlay { common: FxCommon::new(BlendMode::Overlay, 0.5), color: Color::rgb(0.0, 0.0, 1.0) },
             Effect::GradientOverlay { common: FxCommon::new(BlendMode::Normal, 1.0), gradient: g, dither: true },

crates/io/tests/effects_multi.rs

@@ -8,7 +8,7 @@ use photocraft_geom::{Rect, Size};
 use photocraft_io::{ExportOptions, export, import};
 
 fn stroke(size: f32, position: StrokePosition, paint: FxPaint, opacity: f32) -> Effect {
-    Effect::Stroke(StrokeFx { common: FxCommon::new(BlendMode::Normal, opacity), size, position, paint })
+    Effect::Stroke(StrokeFx { common: FxCommon::new(BlendMode::Normal, opacity), size, position, paint, overprint: false })
 }
 
 fn roundtrip(doc: &Document) -> Document {

crates/io/tests/roundtrip.rs

@@ -340,12 +340,14 @@ fn effects_roundtrip_typed_and_raw() {
             size: 3.0,
             position: StrokePosition::Center,
             paint: FxPaint::Color(photocraft_color::Color::rgb(0.0, 1.0, 0.0)),
+            overprint: false,
         }),
         Effect::Stroke(StrokeFx {
             common: FxCommon::new(photocraft_color::BlendMode::Normal, 0.5),
             size: 6.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(photocraft_color::Color::rgb(0.0, 0.0, 1.0)),
+            overprint: false,
         }),
     ];
     let back = roundtrip(&d);

crates/ui-egui/examples/fx_bench.rs

@@ -46,6 +46,7 @@ fn effects() -> Vec<Effect> {
             size: 6.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(Color::rgb(0.95, 0.85, 0.2)),
+            overprint: false,
         }),
         Effect::BevelEmboss(Bevel {
             enabled: true,

crates/ui-egui/examples/huge_doc_bench.rs

@@ -97,6 +97,7 @@ fn text(name: &str, r: Rect) -> Layer {
             size: 4.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(Color::rgb(1.0, 1.0, 1.0)),
+            overprint: false,
         }),
     ];
     l
@@ -144,6 +145,7 @@ fn build(w: u32, h: u32) -> Document {
             size: 3.0,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(Color::rgb(0.1, 0.1, 0.1)),
+            overprint: false,
         }),
     ];
     d.layers.push(band);

crates/ui-egui/src/layer_style.rs

@@ -141,6 +141,7 @@ fn spec(kind: &str) -> &'static [(&'static str, &'static str, P)] {
             ("position", "Position", P::Choice(POS)),
             ("blend", "Blend Mode", P::Blend),
             ("opacity", "Opacity", P::Slider(0.0, 100.0, "%")),
+            ("overprint", "Overprint", P::Check),
             ("color", "Color", P::Color),
         ],
         "colorOverlay" => &[("blend", "Blend Mode", P::Blend), ("color", "Color", P::Color), ("opacity", "Opacity", P::Slider(0.0, 100.0, "%"))],
@@ -266,6 +267,7 @@ fn values_of(e: &Effect, light: f32) -> Value {
                     _ => "outside",
                 }),
             );
+            set(&mut v, "overprint", json!(s.overprint));
             if let FxPaint::Color(c) = &s.paint {
                 set(&mut v, "color", json!(hex(c)));
             } else {
@@ -1634,6 +1636,22 @@ mod tests {
         );
     }
 
+    #[test]
+    fn stroke_overprint_survives_the_dialog() {
+        let mut s = session();
+        s.execute("layer.layerStyle.stroke", json!({"size": 3, "color": "#000000", "overprint": true})).unwrap();
+        let st = s.active().unwrap();
+        let id = st.active_layer.unwrap();
+        let mut f = initial_fields(st.doc.layer(id).unwrap(), None, st.doc.global_light.angle);
+        assert_eq!(effects_of(&f)[0]["params"]["overprint"], json!(true));
+        // Editing another setting keeps Overprint.
+        set_param(&mut f, "fx1", "size", json!(5));
+        apply(&f, |cmd, p| s.execute(cmd, p).map_err(|e| e.to_string())).unwrap();
+        let strokes = strokes_of(&s);
+        assert_eq!(strokes[0].size, 5.0);
+        assert!(strokes[0].overprint);
+    }
+
     #[test]
     fn preview_applies_the_style_without_touching_the_document() {
         let s = session();

crates/ui-egui/src/transform_fx.rs

@@ -429,6 +429,7 @@ mod tests {
             size,
             position: StrokePosition::Outside,
             paint: FxPaint::Color(Color::rgb(1.0, 0.0, 0.0)),
+            overprint: false,
         })
     }
 

crates/ui-egui/tests/support/layout_doc.rs

@@ -88,6 +88,7 @@ fn stroke_fx(size: f32, c: [f32; 3]) -> Effect {
         size,
         position: StrokePosition::Outside,
         paint: FxPaint::Color(Color::rgb(c[0], c[1], c[2])),
+        overprint: false,
     })
 }
 

docs/file-format-parity.md

@@ -142,6 +142,7 @@ remaining gaps in #1606 stay tracked with per-sample corpus ceilings.
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-15 | minor | Stroke › Overprint (`overprint`) is read and written, set by the stroke command's `overprint` and shown in the Layer Style dialog; an edited stroke no longer drops it. Rendering ignores it for now |
 | 2026-10-14 | minor | PSD smart filter masks: Photoshop stores a smart object's filtered pixels without its filter mask and mixes the unfiltered ones (`FEid`) back in; import now mixes them and export writes them that way, so sf-filter-mask-hard, -gradient and sf-stack-blend-and-mask pass; Photoshop-oracle floor 185 → 188 of 258 |
 | 2026-10-13 | minor | Lossy DNG (compression 34892) decodes: 8-bit baseline JPEG tiles and strips, CFA and LinearRaw, partial edge tiles; the stored values take the normal levels and LinearizationTable (FILE-215-11, lossy DNG part) |
 | 2026-10-14 | minor | Corpus floors raised to the measured results of the CMYK, Lab, 32-bit, Levels, Threshold, Posterize, feather and pass-through fixes landed together: Photoshop-authored 165 → 185 of 258, io 146 → 148 of 170, psd-tools 242 → 249 of 309 |