Merge section-marker: Sections: the section marker shows the section's marker text (#556)

Conflict: ROADMAP.md: both progress lines (next's, then #556's)
Conflict: crates/compose/src/shape.rs: #556's empty-marker zero-width glyph; next's digit mapping, styles.at(i)/styles and sub.upright() in both arms

ROADMAP.md

@@ -137,6 +137,7 @@ Newest first.
   readiness percentage change.
 - **2026-10-12** · Properties › Transform shows rotation, shear and X/Y scale, and Rotate 90° and Flip Horizontal/Vertical buttons, as InDesign's does. No readiness percentage change.
 - **2026-10-12** · Underlines and strikethroughs are drawn as one bar per stretch of text on screen, as in PDF export: a bar per letter left faint seams between the letters. No readiness percentage change.
+- **2026-10-12** · The section marker character shows its section's marker text on document pages (nothing when the section has none) instead of the word "Section", which stays on parent pages; editing the marker recomposes (#556). No readiness percentage change.
 - **2026-10-12** · Words in capitals hyphenate like capitalized words (FERRUM COM-MODI), as in InDesign; Hyphenate Capitalized Words off keeps them whole. No readiness percentage change.
 - **2026-10-11 (printing):** `file.printers` and `file.print` use craft-libs/craft-print for CUPS and Windows. DesignCraft retains PDF export, page selection, spreads, marks and bleed; dry runs create no temporary PDF or print job. Windows selects matching or default driver paper and shrinks oversized sheets without enlarging smaller ones; queue duplex defaults are preserved. Headless tests exercise exported bytes, job settings, dry runs and refusals; shared native Windows CI passes, including paused-queue submission and cleanup. PostScript, production print controls and physical output validation remain open. No readiness percentage change.
 - **2026-10-11** · The View menu follows InDesign's: proofing first, then zoom, Rotate Spread, Screen Mode, Display Performance, rulers, Extras, Grids & Guides and Structure; the view items that sat at the end of the Type menu moved there. No readiness percentage change.

crates/compose/src/cache.rs

@@ -67,10 +67,18 @@ impl Cache {
         // The key holds the page's index, which a renumbering doesn't change: its name (section
         // start number, style, prefix) is part of the signature.
         let page_name = page.map(|p| doc.page_name(p));
+        let section_marker = page.map(|p| crate::section_marker(doc, p));
         if let Some(name) = &page_name {
             use std::hash::{Hash, Hasher};
             let mut h = std::collections::hash_map::DefaultHasher::new();
-            name.hash(&mut h);
+            (name, &section_marker).hash(&mut h);
+            sig.push(h.finish() as usize);
+        }
+        if story.text.contains(designcraft_doc::story::SECTION_MARKER) {
+            // Frames on document pages show their section's marker text.
+            use std::hash::{Hash, Hasher};
+            let mut h = std::collections::hash_map::DefaultHasher::new();
+            doc.sections.iter().for_each(|s| (s.start, &s.marker).hash(&mut h));
             sig.push(h.finish() as usize);
         }
         let with_vars = crate::vars::has_vars(story);
@@ -146,7 +154,7 @@ impl Cache {
         let out = Arc::new(crate::compose_story(
             doc,
             sid,
-            &ComposeOptions { page_name, page, running, label: None, xrefs: with_xrefs.then(|| self.xref_index(doc)) },
+            &ComposeOptions { page_name, section_marker, page, running, label: None, xrefs: with_xrefs.then(|| self.xref_index(doc)) },
         ));
         let mut g = self.map.lock().unwrap_or_else(|e| e.into_inner());
         let stamp = g.1;

crates/compose/src/lib.rs

@@ -485,6 +485,8 @@ pub struct FrameSpec {
     pub vertical: bool,
     pub exclusions: Vec<Exclusion>,
     pub page_name: Option<String>,
+    /// Marker text of the section the frame's page is in (None on parent pages).
+    pub section_marker: Option<String>,
     /// Absolute document page the frame is on (None on parent pages).
     pub page: Option<usize>,
     /// Baseline grid in inner space: (first grid line y, increment).
@@ -511,11 +513,18 @@ impl FrameSpec {
     }
 }
 
+/// The marker text of the section absolute page `abs` is in (empty when it has none).
+pub fn section_marker(doc: &Document, abs: usize) -> String {
+    doc.section_of(abs).map(|s| s.marker.clone()).unwrap_or_default()
+}
+
 /// Composition inputs that are not in the story itself.
 #[derive(Clone, Debug, Default)]
 pub struct ComposeOptions {
     /// Page name for page-number markers when the story is composed for a specific page (parent items).
     pub page_name: Option<String>,
+    /// Section marker text when the story is composed for a specific page (parent items).
+    pub section_marker: Option<String>,
     /// Absolute page for text variables when composed for a specific page (parent items).
     pub page: Option<usize>,
     /// Running-header index (needed when the story contains running-header variables).
@@ -592,6 +601,7 @@ pub fn frame_specs(doc: &Document, sid: StoryId) -> Vec<FrameSpec> {
             }
             _ => (None, None, false),
         };
+        let section_marker = page.map(|abs| section_marker(doc, abs));
         // The page under the frame and its margins, in inner space (bounding boxes).
         let page_rect = match (spread_ref, spread) {
             (_, Some(sp)) => sp
@@ -650,6 +660,7 @@ pub fn frame_specs(doc: &Document, sid: StoryId) -> Vec<FrameSpec> {
             vertical,
             exclusions: if tf.options.path.is_some() { vec![] } else { exclusions },
             page_name,
+            section_marker,
             page,
             grid,
             left_page,
@@ -835,7 +846,7 @@ fn compose_with_db(doc: &Document, story: &Story, frames: &[FrameSpec], opts: &C
         };
         let mut sub = SubstCtx {
             page_name: opts.page_name.clone().or_else(|| cur_frame.and_then(|f| f.page_name.clone())),
-            section_marker: None,
+            section_marker: opts.section_marker.clone().or_else(|| cur_frame.and_then(|f| f.section_marker.clone())),
             vars: var_values,
             hidden_conditions: doc.conditions.iter().filter(|c| !c.visible).map(|c| c.name.clone()).collect(),
             vertical: cur_frame.is_some_and(|f| f.vertical),

crates/compose/src/notes.rs

@@ -102,6 +102,7 @@ impl Notes {
             vertical: false,
             exclusions: vec![],
             page_name: f.page_name.clone(),
+            section_marker: f.section_marker.clone(),
             page: f.page,
             grid: None,
             left_page: f.left_page,
@@ -109,6 +110,7 @@ impl Notes {
         };
         let nopts = ComposeOptions {
             page_name: opts.page_name.clone(),
+            section_marker: opts.section_marker.clone(),
             page: opts.page,
             running: opts.running.clone(),
             label: Some(label),

crates/compose/src/shape.rs

@@ -171,6 +171,7 @@ fn shaping_key(p: &CharProps) -> CharProps {
 #[derive(Clone, Debug, Default)]
 pub struct SubstCtx {
     pub page_name: Option<String>,
+    /// The section marker text of the page being composed (`None` on parent pages: "Section").
     pub section_marker: Option<String>,
     /// Text variable values by index (on the page being composed).
     pub vars: Arc<Vec<String>>,
@@ -871,9 +872,16 @@ fn shape_run_raw(
                     } else {
                         sub.page_name.clone().unwrap_or_else(|| "#".into())
                     };
-                    // Page numbers take the digits of the text they stand in.
-                    let s: String = s.chars().map(|ch| digits.map(ch, &p.language)).collect();
-                    shape_segment(db, text, i..i + c.len_utf8(), Some(&s), p, &primary, auto_leading, styles, out, sub.upright());
+                    if s.is_empty() {
+                        // A section without marker text: the character takes no space.
+                        let mut g = control_glyph(&primary, p, auto_leading, styles.at(i), i, c);
+                        g.adv = 0.0;
+                        out.push(g);
+                    } else {
+                        // Page numbers take the digits of the text they stand in.
+                        let s: String = s.chars().map(|ch| digits.map(ch, &p.language)).collect();
+                        shape_segment(db, text, i..i + c.len_utf8(), Some(&s), p, &primary, auto_leading, styles, out, sub.upright());
+                    }
                 }
                 designcraft_doc::OBJECT_MARK => {
                     let mut g = control_glyph(&primary, p, auto_leading, styles.at(i), i, c);

crates/compose/src/table.rs

@@ -129,6 +129,7 @@ fn compose_cell(doc: &Document, cell: &Cell, w: f64, opts: &ComposeOptions, left
         vertical: false,
         exclusions: vec![],
         page_name: opts.page_name.clone(),
+        section_marker: opts.section_marker.clone(),
         page: opts.page,
         grid: None,
         left_page,

crates/engine/src/cmd/variables.rs

@@ -153,6 +153,38 @@ mod tests {
         assert_eq!(shown(&s, 2), 3, "page 102 after renumbering");
     }
 
+    /// A section marker character shows the marker text of the section of the page it is composed
+    /// for: on each document page a parent-page frame is shown on, and in a frame on a document
+    /// page. A section without marker text shows nothing; the parent page itself shows "Section".
+    #[test]
+    fn section_marker_shows_the_pages_section_marker() {
+        let mut s = Session::new();
+        s.execute("file.new", &json!({"pages": 4, "facingPages": false})).unwrap();
+        s.execute("layout.section", &json!({"page": 3, "startNumber": 1, "marker": "Intro"})).unwrap();
+        let marker = designcraft_doc::story::SECTION_MARKER.to_string();
+        let r = s
+            .execute("frame.create", &json!({"spread": {"kind": "parent", "index": 0}, "rect": [72, 30, 500, 60], "content": "text", "text": marker}))
+            .unwrap();
+        let parent = s.doc().unwrap().doc.item(designcraft_doc::ItemId(r["id"].as_u64().unwrap())).unwrap().text_frame().unwrap().story;
+        let sp = s.doc().unwrap().doc.page_loc(3).unwrap().0;
+        let r = s.execute("frame.create", &json!({"spread": sp, "rect": [72, 200, 400, 260], "content": "text", "text": marker})).unwrap();
+        let own = s.doc().unwrap().doc.item(designcraft_doc::ItemId(r["id"].as_u64().unwrap())).unwrap().text_frame().unwrap().story;
+        let shown = |s: &Session, sid, page: Option<usize>| -> usize {
+            let d = s.doc().unwrap().doc.clone();
+            let cs = s.cache.get(&d, sid, page);
+            cs.frames.iter().flat_map(|f| f.lines.iter()).map(|l| l.glyphs.iter().filter(|g| g.visible && g.adv > 0.0).count()).sum()
+        };
+        assert_eq!(shown(&s, parent, Some(0)), 0, "the first section has no marker");
+        assert_eq!(shown(&s, parent, Some(2)), "Intro".len());
+        assert_eq!(shown(&s, parent, Some(3)), "Intro".len());
+        assert_eq!(shown(&s, own, None), "Intro".len(), "a frame on a document page");
+        assert_eq!(shown(&s, parent, None), "Section".len(), "the parent page itself");
+        // Editing the marker recomposes.
+        s.execute("layout.section", &json!({"page": 3, "marker": "Appendix"})).unwrap();
+        assert_eq!(shown(&s, parent, Some(2)), "Appendix".len());
+        assert_eq!(shown(&s, own, None), "Appendix".len());
+    }
+
     /// Two sections that both number from 1 repeat page names ("1, 2, 1, 2"). A parent-page running
     /// header is composed for the page it is shown on, not the first page with that name.
     #[test]