C: Transparency Blend Space setting (+ IDML)

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

ROADMAP.md

@@ -49,6 +49,7 @@ DesignCraft aims at full Adobe InDesign parity — and to be better: faster, ope
 - Endnotes (`endnote.insert/edit/delete/list/options`, Type ▸ Insert Endnote): references number through the document, the endnote frame on a new last page lists them under a heading; IDML keeps the listed text only.
 - Editorial notes (`note.new/edit/delete/convertToText/list`, Notes panel): anchored in text, flagged on screen, never printed or exported.
 - File ▸ Print Booklet (`file.printBooklet`): saddle-stitch or 2-up consecutive printer spreads as PDF, padded with blanks, with a gap between pages.
+- Edit ▸ Transparency Blend Space (`edit.transparencyBlendSpace`; RGB for web/mobile documents; IDML TransparencyPreference) — stored; compositing is still RGB on screen and in PDF.
 - Drag and drop text editing: drag selected text to move it (Alt copies) with its formatting (`text.release`).
 - Image Import Options: place any page of a multi-page PDF (`file.place {pdfPage}`; the app asks which page), shown on screen and embedded as that page in PDF export.
 - Define Lists: named numbered lists that continue across stories in page order (`list.define`, paragraph `listName` / `startAt`), round-tripped through IDML; `null` in `type.para` / `type.char` now removes an override.

crates/doc/src/build.rs

@@ -115,6 +115,7 @@ impl Document {
             slug: nd.slug,
             horizontal_units: nd.units,
             vertical_units: nd.units,
+            blend_space: if nd.intent == Intent::Print { crate::BlendSpace::Cmyk } else { crate::BlendSpace::Rgb },
             ..Default::default()
         };
         let mut d = Document {

crates/doc/src/lib.rs

@@ -68,6 +68,16 @@ pub enum DocError {
 
 pub type Result<T> = std::result::Result<T, DocError>;
 
+/// Edit › Transparency Blend Space: the colour space transparency is flattened in (CMYK for
+/// print documents, RGB for screen ones, as InDesign defaults).
+#[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
+#[serde(rename_all = "camelCase")]
+pub enum BlendSpace {
+    #[default]
+    Cmyk,
+    Rgb,
+}
+
 #[derive(Clone, Copy, Debug, Default, PartialEq, Eq, Serialize, Deserialize)]
 #[serde(rename_all = "camelCase")]
 pub enum Intent {
@@ -210,6 +220,8 @@ pub struct DocSettings {
     /// Preferences › Advanced Type: superscript and subscript size and position (percent of the
     /// font size).
     pub advanced_type: AdvancedType,
+    /// Edit › Transparency Blend Space.
+    pub blend_space: BlendSpace,
 }
 
 impl Default for DocSettings {
@@ -237,6 +249,7 @@ impl Default for DocSettings {
             chapter_number: 1,
             global_light: 120.0,
             advanced_type: AdvancedType::default(),
+            blend_space: BlendSpace::Cmyk,
         }
     }
 }

crates/engine/src/cmd/prefs.rs

@@ -23,6 +23,24 @@ const DOC_KEYS: &[&str] = &[
 
 pub fn specs() -> Vec<CommandSpec> {
     vec![
+        cmd!(
+            "edit.transparencyBlendSpace",
+            "Transparency Blend Space",
+            ["Edit", "Transparency Blend Space"],
+            None,
+            "{space: cmyk|rgb} — the colour space transparency is composited in for output",
+            has_doc,
+            |s, p| {
+                let space: designcraft_doc::BlendSpace = p
+                    .get("space")
+                    .and_then(|v| serde_json::from_value(v.clone()).ok())
+                    .ok_or_else(|| bad("edit.transparencyBlendSpace", "`space`: cmyk or rgb"))?;
+                s.edit(|d, _| {
+                    d.settings.blend_space = space;
+                    Ok(serde_json::json!({"space": space}))
+                })
+            }
+        ),
         cmd!(
             noundo "prefs.set",
             "Preferences",
@@ -227,3 +245,21 @@ mod keep_highlight_tests {
         assert!(flagged(&s), "too long to keep together in one column");
     }
 }
+
+#[cfg(test)]
+mod blend_space_tests {
+    use serde_json::json;
+
+    use crate::Session;
+
+    #[test]
+    fn blend_space_is_set_and_kept_in_idml() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({})).unwrap();
+        assert_eq!(s.doc().unwrap().doc.settings.blend_space, designcraft_doc::BlendSpace::Cmyk);
+        s.execute("edit.transparencyBlendSpace", &json!({"space": "rgb"})).unwrap();
+        let back = designcraft_idml::import_idml(&designcraft_idml::export_idml(&s.doc().unwrap().doc)).unwrap();
+        assert_eq!(back.settings.blend_space, designcraft_doc::BlendSpace::Rgb);
+        assert!(s.execute("edit.transparencyBlendSpace", &json!({"space": "lab"})).is_err());
+    }
+}

crates/idml/src/export.rs

@@ -704,6 +704,13 @@ impl<'a> Ex<'a> {
         );
         root.push(El::new("PasteboardPreference").attr("PasteboardMargins", pt(s.pasteboard.0, s.pasteboard.1)));
         root.push(self.footnote_option_el());
+        root.push(El::new("TransparencyPreference").attr(
+            "BlendingSpace",
+            match s.blend_space {
+                designcraft_doc::BlendSpace::Cmyk => "CMYK",
+                designcraft_doc::BlendSpace::Rgb => "RGB",
+            },
+        ));
         let a = &s.advanced_type;
         root.push(
             El::new("TextPreference")

crates/idml/src/import.rs

@@ -219,6 +219,11 @@ impl<'r> Importer<'r> {
         for e in top {
             match e.local() {
                 "DocumentPreference" => self.doc_prefs(e),
+                "TransparencyPreference" => {
+                    if let Some(v) = e.get("BlendingSpace") {
+                        self.settings.blend_space = if v == "RGB" { designcraft_doc::BlendSpace::Rgb } else { designcraft_doc::BlendSpace::Cmyk };
+                    }
+                }
                 "TextPreference" => {
                     let a = &mut self.settings.advanced_type;
                     for (k, v) in [

crates/ui-egui/src/menus.rs

@@ -146,6 +146,10 @@ pub const MENUS: &[(&str, &[&str])] = &[
             "cmd:spelling.check",
             "cmd:spelling.addWord",
             "<",
+            ">Transparency Blend Space",
+            "cmd:edit.transparencyBlendSpace|Document RGB|{\"space\": \"rgb\"}",
+            "cmd:edit.transparencyBlendSpace|Document CMYK|{\"space\": \"cmyk\"}",
+            "<",
             "-",
             "ui:app.palette",
             "ui:app.keyboardShortcuts",

docs/parity.md

@@ -10,7 +10,7 @@ Each row of the InDesign feature catalogue is scored **D** (done), **P** (partia
 | Priority | Features | Done | Partial | Missing | Parity |
 |---|---|---|---|---|---|
 | P0 | 102 | 99 | 3 | 0 | 99% |
-| P1 | 97 | 75 | 20 | 2 | 88% |
+| P1 | 97 | 75 | 21 | 1 | 88% |
 | P2 | 76 | 19 | 13 | 44 | 34% |
 
 | Area | Parity |
@@ -21,7 +21,7 @@ Each row of the InDesign feature catalogue is scored **D** (done), **P** (partia
 | Frames, shapes & paths | 93% |
 | Transform | 100% |
 | Fill, stroke, colour | 88% |
-| Effects & transparency | 62% |
+| Effects & transparency | 71% |
 | Placing & links | 82% |
 | Type & text frames | 92% |
 | Typography | 88% |
@@ -164,7 +164,7 @@ Open P0 items: Preferences, Vector/page formats (PDF/AI/SVG/EPS place), Export t
 | Effects & transparency | Inner Shadow, Outer Glow, Inner Glow, Bevel, Satin | P2 | P |
 | Effects & transparency | Basic/Directional/Gradient Feather | P2 | P |
 | Effects & transparency | Global Light | P2 | D |
-| Effects & transparency | Transparency blend space | P1 | M |
+| Effects & transparency | Transparency blend space | P1 | P |
 | Effects & transparency | Transparency flattener | P2 | M |
 | Placing & links | Place | P0 | D |
 | Placing & links | Place into frame / by click or drag | P0 | D |