PPTX: the notes master's own placeholders and colour map are kept on save

crates/pptx/src/write/mod.rs

@@ -434,8 +434,8 @@ pub fn export(p: &Presentation) -> Result<Vec<u8>, PptxError> {
         master_rids.push((master_id, pres.rels.add("slideMaster", &opc::relative("ppt/presentation.xml", &mname), false)));
     }
 
-    // Notes master when any slide has notes.
-    let has_notes = p.slides.iter().any(|s| !s.notes.is_empty());
+    // Notes master when the deck has one or any slide has notes.
+    let has_notes = p.notes_master.is_some() || p.slides.iter().any(|s| !s.notes.is_empty());
     let notes_master = "ppt/notesMasters/notesMaster1.xml";
     let mut notes_master_rid = None;
     if has_notes {
@@ -449,9 +449,22 @@ pub fn export(p: &Presentation) -> Result<Vec<u8>, PptxError> {
         x.pkg.rels(&tname, &to.rels);
         let mut w = W::new();
         root_open(&mut w, "p:notesMaster", A::new());
-        let bg = Background::Ref { idx: 1001, color: deckcraft_model::ColorRef::scheme(deckcraft_color::SchemeSlot::Bg1) };
-        csld(&mut w, &mut x, &mut no, "", Some(&bg), &notes_master_shapes(p.notes_size));
-        clr_map(&mut w, &[]);
+        let nm = p.notes_master.as_deref();
+        let bg = nm
+            .and_then(|m| m.background.clone())
+            .unwrap_or(Background::Ref { idx: 1001, color: deckcraft_model::ColorRef::scheme(deckcraft_color::SchemeSlot::Bg1) });
+        // The file's own placeholders are kept; PowerPoint's defaults only when it has none.
+        let own = nm.map(|m| m.shapes.as_slice()).filter(|s| !s.is_empty());
+        let defaults;
+        let list = match own {
+            Some(s) => s,
+            None => {
+                defaults = notes_master_shapes(p.notes_size);
+                defaults.as_slice()
+            }
+        };
+        csld(&mut w, &mut x, &mut no, "", Some(&bg), list);
+        clr_map(&mut w, nm.map(|m| m.color_map.as_slice()).unwrap_or(&[]));
         dml::list_style(&mut w, &mut x, &mut no, "p:notesStyle", &notes_style());
         w.close("p:notesMaster");
         x.pkg.xml_part(notes_master, CT_NOTES_MASTER, w.finish());

crates/pptx/tests/roundtrip.rs

@@ -991,3 +991,37 @@ fn transition_defaults_read_like_powerpoint() {
         assert_eq!((t.kind.as_str(), t.option.as_str(), t.duration_ms), (*kind, *option, 2000), "{el}");
     }
 }
+
+#[test]
+fn notes_master_placeholders_and_colour_map_survive_save() {
+    let mut p = defaults::new_presentation(None);
+    let mut box1 = shape(&mut p, "Confidential", 100000.0, 200000.0, 3000000.0, 400000.0);
+    box1.text = Some(TextBody::from_text("Company confidential"));
+    let map: Vec<(String, String)> = [("bg1", "dk1"), ("tx1", "lt1"), ("bg2", "dk2"), ("tx2", "lt2")]
+        .iter()
+        .chain(
+            [
+                ("accent1", "accent1"),
+                ("accent2", "accent2"),
+                ("accent3", "accent3"),
+                ("accent4", "accent4"),
+                ("accent5", "accent5"),
+                ("accent6", "accent6"),
+                ("hlink", "hlink"),
+                ("folHlink", "folHlink"),
+            ]
+            .iter(),
+        )
+        .map(|(a, b)| (a.to_string(), b.to_string()))
+        .collect();
+    let m = deckcraft_model::Master { name: "Notes Master".into(), shapes: vec![box1], color_map: map.clone(), ..Default::default() };
+    p.notes_master = Some(Arc::new(m));
+    // No slide has notes: the notes master must still be written.
+    let q = round(&p);
+    let nm = q.notes_master.as_deref().expect("notes master kept");
+    assert_eq!(nm.shapes.len(), 1, "own shapes, not the defaults");
+    let sh = &nm.shapes[0];
+    assert_eq!(sh.name, "Confidential");
+    assert_eq!(sh.text.as_ref().map(|t| t.text()), Some("Company confidential".to_string()));
+    assert_eq!(nm.color_map, map);
+}