Text: underline an IME composition in a table cell

The preedit was already stored in the cell. It is now laid out the same
way the cell is drawn, and the editor underlines it in place, thicker
under the part being converted. The caret and the input method's
candidate window sit in that cell. Notes stay an egui text field.

Co-authored-by: Cursor <cursoragent@cursor.com>

ROADMAP.md

@@ -2,7 +2,7 @@
 
 **Stage: alpha** · next: beta, ~20 points and ~120–210 h away
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-10 · **Change:** minor (hours to ~95% per audience added; ready 56% → 55%; stage stays alpha; previous: major, full re-measure against PowerPoint for Mac 16.113.4; restructured to the craftrules progress-docs standard) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-14 · **Last updated:** 2026-10-14 · **Change:** trivial (progress log: IME underlines in table cells; previous: minor, hours to ~95% per audience added; ready 56% → 55%; stage stays alpha) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 DeckCraft aims at full PowerPoint parity, and to be better: faster, open (a documented zip+JSON
 format plus PPTX), scriptable by agents (CLI, JSON control channel, MCP), and available everywhere
@@ -128,6 +128,7 @@ app's JSON control channel (`deckcraft --control PORT`).
 
 | Date | What landed |
 |---|---|
+| 2026-10-14 | Text: an input method's composition in a table cell is underlined in place, with the caret and candidate window in that cell |
 | 2026-10-13 | Slide transitions like PowerPoint: every transition and option measured frame by frame against PowerPoint's video export and retuned (curves, directions, soft edges, 3-D perspective, contents moving over backgrounds); PowerPoint's own XML elements and defaults read and written (diagonal Wipe, Zoom, Shape In/Out, Glitter Hexagons, Shred In/Out, Page Curl Single); `deckcraft-cli render-transition` renders frames headless |
 | 2026-10-13 | Wild text cases measured against PowerPoint (102 synthetic slides): bidi by run language, East Asian vertical text upright, mongolianVert/wordArtVert/wordArtVertRtl, underline styles and strikethrough at the font's metrics, centre/right/decimal tabs, East Asian, Thai, Hindi, Arabic and Hebrew numbering, small caps, all-caps "ß", transparent text, soft hyphens, kinsoku, rtlCol and just/dist anchoring, emoji presentation, fallback faces that no longer move the baseline |
 | 2026-10-13 | Render matches PowerPoint more closely on wild shape, picture and table cases: even-odd custom paths, dashes and caps, arrowheads, radial and path gradients, tile rects, rotWithShape, gradient lines, shadows cast by what is drawn (group and perspective too), group fill, picture borders, tiles, reflection, recolour (biLevel, alphaInv, brightness/contrast), table borders and grid default, 20+ preset shapes by their ECMA formulas, default miter joins, and approximate 3-D bevels, cameras and face lighting |
@@ -150,6 +151,7 @@ app's JSON control channel (`deckcraft --control PORT`).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-14 | trivial | Progress log: IME underlines in table cells |
 | 2026-10-13 | trivial | Progress log: wild text cases |
 | 2026-10-12 | trivial | Progress log: File tab (Backstage, #76) |
 | 2026-10-12 | trivial | Progress log: lines in scaled groups (#233) |

crates/engine/src/cmd/text.rs

@@ -177,12 +177,18 @@ pub fn layout_for(st: &DocState, t: &TextSel) -> Option<deckcraft_text::TextLayo
 
 /// The insertion point on the slide: its line from top to bottom, in slide coordinates (flips and
 /// vertical text as drawn). Text with no paragraph yet (a placeholder about to be typed in) is
-/// measured as one empty paragraph, so the caret shows where typing begins. `None` for notes and
-/// table cells, which aren't laid out on the slide here.
+/// measured as one empty paragraph, so the caret shows where typing begins. `None` for notes,
+/// which are an egui text field.
 pub fn caret_line(st: &DocState, t: &TextSel) -> Option<(deckcraft_geom::Point, deckcraft_geom::Point)> {
-    if t.notes || t.cell.is_some() {
+    if t.notes {
         return None;
     }
+    if let Some((row, col)) = t.cell {
+        let placed = cell_on_slide(st, t.shape, row, col)?;
+        let aff = if t.at_line_end() { deckcraft_text::Affinity::Upstream } else { deckcraft_text::Affinity::Downstream };
+        let (cx, top, bot) = placed.layout.caret_drawn(deckcraft_text::Pos { para: t.caret.0, ch: t.caret.1 }, aff)?;
+        return Some((placed.to_slide * deckcraft_geom::Point::new(cx, top), placed.to_slide * deckcraft_geom::Point::new(cx, bot)));
+    }
     let sh = st.shape(t.shape)?;
     let ctx = ctx_for(&st.doc, &st.selection)?;
     let x = xfrm_of(&st.doc, &st.selection, sh);
@@ -483,20 +489,35 @@ fn commit(s: &mut Session, p: &Value) -> Result<Value> {
 }
 
 /// Underlines under an input method's composition (#101), in slide coordinates: `(from, to,
-/// thick)` per line, thick under the part being converted. Empty without a composition or when
-/// the edited text isn't laid out on the slide (notes, table cells).
+/// thick)` per line, thick under the part being converted. Empty without a composition, or for
+/// notes (an egui text field draws its own composition).
 pub fn composition_underlines(st: &DocState) -> Vec<(deckcraft_geom::Point, deckcraft_geom::Point, bool)> {
     let (Some(c), Some(t)) = (&st.composition, &st.selection.text) else { return vec![] };
+    if t.notes {
+        return vec![];
+    }
+    if let Some((row, col)) = t.cell {
+        let Some(placed) = cell_on_slide(st, t.shape, row, col) else { return vec![] };
+        return underline_segments(&placed.layout, placed.to_slide, c);
+    }
     let Some(sh) = st.shape(t.shape) else { return vec![] };
     let Some(l) = layout_for(st, t) else { return vec![] };
     let x = xfrm_of(&st.doc, &st.selection, sh);
     let tr = deckcraft_render::shape_geometry(sh, x.w, x.h).text_rect;
     let m = deckcraft_render::text_transform(x.affine(), tr, l.rotation);
+    underline_segments(&l, m, c)
+}
+
+fn underline_segments(
+    layout: &deckcraft_text::TextLayout,
+    to_slide: deckcraft_geom::Affine,
+    c: &crate::Composition,
+) -> Vec<(deckcraft_geom::Point, deckcraft_geom::Point, bool)> {
     let pos = |ch: usize| deckcraft_text::Pos { para: c.start.0, ch: c.start.1 + ch };
     let mut out = vec![];
     let mut add = |a: usize, b: usize, thick: bool| {
-        for (x0, x1, y) in l.composition_underlines(pos(a), pos(b)) {
-            out.push((m * deckcraft_geom::Point::new(x0, y), m * deckcraft_geom::Point::new(x1, y), thick));
+        for (x0, x1, y) in layout.composition_underlines(pos(a), pos(b)) {
+            out.push((to_slide * deckcraft_geom::Point::new(x0, y), to_slide * deckcraft_geom::Point::new(x1, y), thick));
         }
     };
     add(0, c.len, false);
@@ -506,6 +527,35 @@ pub fn composition_underlines(st: &DocState) -> Vec<(deckcraft_geom::Point, deck
     out
 }
 
+/// A table cell's text laid out the way it is drawn, mapped into slide coordinates.
+fn cell_on_slide(st: &DocState, id: ShapeId, row: usize, col: usize) -> Option<CellText> {
+    let sh = st.shape(id)?;
+    let ShapeKind::Table(tb) = &sh.kind else { return None };
+    let cell = tb.cell(row, col)?;
+    let ctx = ctx_for(&st.doc, &st.selection)?;
+    let heights = super::table_drawn_heights(&st.doc, &st.selection, tb);
+    let rect = deckcraft_render::table_cell_rects(tb, &heights).into_iter().find(|(r, c, _)| *r == row && *c == col)?.2;
+    let mut body = deckcraft_render::table_cell_body(&ctx, tb, row, col, cell);
+    if body.paragraphs.is_empty() {
+        body.paragraphs.push(deckcraft_model::text::Paragraph::default());
+    }
+    let tmp = deckcraft_model::Shape { text: Some(body.clone()), ..Default::default() };
+    let layout = deckcraft_text::layout(
+        &ctx,
+        &tmp,
+        &body,
+        &deckcraft_text::Opts { rect, fields: &deckcraft_text::NoFields, prompt_color: None, no_shrink: false },
+    );
+    let x = xfrm_of(&st.doc, &st.selection, sh);
+    let to_slide = deckcraft_render::text_transform(x.affine(), rect, layout.rotation);
+    Some(CellText { layout, to_slide })
+}
+
+struct CellText {
+    layout: deckcraft_text::TextLayout,
+    to_slide: deckcraft_geom::Affine,
+}
+
 fn insert(s: &mut Session, p: &Value) -> Result<Value> {
     let text = str_param(p, "text").ok_or_else(|| bad("text.insert", "missing `text`"))?.to_string();
     insert_text(s, &text, None)

crates/engine/src/tests.rs

@@ -775,6 +775,41 @@ fn ime_composition_underlines_follow_the_text() {
     assert!(cmd::text::composition_underlines(s.doc().unwrap()).is_empty());
 }
 
+/// #101: a composition in a table cell is underlined inside that cell, the same way slide text is.
+#[test]
+fn ime_composition_in_a_table_cell_is_underlined() {
+    let mut s = session();
+    let id = s.execute("insert.table", &json!({"rows": 2, "cols": 2, "rect": [80.0, 90.0, 400.0, 120.0]})).unwrap()["id"].as_u64().unwrap();
+    s.execute("text.edit", &json!({"id": id, "cell": [0, 0]})).unwrap();
+    assert!(cmd::text::composition_underlines(s.doc().unwrap()).is_empty());
+    let ts = s.doc().unwrap().selection.text.clone().unwrap();
+    assert!(cmd::text::caret_line(s.doc().unwrap(), &ts).is_some(), "the caret is in the cell");
+    s.compose_text("にほんご", Some((2, 4))).unwrap();
+    let u = cmd::text::composition_underlines(s.doc().unwrap());
+    let thin: Vec<_> = u.iter().filter(|x| !x.2).collect();
+    let thick: Vec<_> = u.iter().filter(|x| x.2).collect();
+    assert_eq!((thin.len(), thick.len()), (1, 1), "{u:?}");
+    let sh = s.doc().unwrap().shape(deckcraft_model::ShapeId(id as u32)).unwrap().clone();
+    let x = cmd::xfrm_of(&s.doc().unwrap().doc, &s.doc().unwrap().selection, &sh);
+    let deckcraft_model::ShapeKind::Table(tb) = &sh.kind else { panic!("not a table") };
+    let col = tb.cols[0];
+    let row = cmd::table_drawn_heights(&s.doc().unwrap().doc, &s.doc().unwrap().selection, tb)[0];
+    for (a, b, _) in &u {
+        assert!(b.x > a.x && (a.y - b.y).abs() < 1e-6, "a horizontal line: {a:?} {b:?}");
+        assert!(a.x >= x.x - 1.0 && b.x <= x.x + col + 1.0, "inside the first column");
+        assert!(a.y > x.y && a.y < x.y + row + 1.0, "inside the first row");
+    }
+    assert!(thick[0].0.x > thin[0].0.x && (thick[0].1.x - thin[0].1.x).abs() < 1e-6, "the converted part is the end");
+    let ts = s.doc().unwrap().selection.text.clone().unwrap();
+    let (top, bot) = cmd::text::caret_line(s.doc().unwrap(), &ts).unwrap();
+    assert!(top.x >= x.x && top.x <= x.x + col && top.y >= x.y && bot.y <= x.y + row + 1.0, "caret in the cell");
+    s.commit_text("日本語").unwrap();
+    assert!(cmd::text::composition_underlines(s.doc().unwrap()).is_empty());
+    let sh = s.doc().unwrap().shape(deckcraft_model::ShapeId(id as u32)).unwrap().clone();
+    let deckcraft_model::ShapeKind::Table(tb) = &sh.kind else { panic!("not a table") };
+    assert_eq!(tb.cell(0, 0).map(|c| c.text.text()), Some("日本語".into()));
+}
+
 /// File › Info (#76): the active presentation's name, location, counts and properties.
 #[test]
 fn file_info_reports_the_presentation() {

crates/render/src/lib.rs

@@ -50,6 +50,8 @@ pub use images::{decode as decode_image, gif_frame};
 pub use morph_path::PathMorph;
 pub use morph_text::TextMorph;
 pub use placed::{Placed, PlacedLink, PlacedText, place_slide};
+pub use table::cell_body as table_cell_body;
+pub use table::cell_rects as table_cell_rects;
 pub use table::row_heights as table_row_heights;
 pub use transition::{SlideParts, composite_transition, render_transition};
 

crates/render/src/table.rs

@@ -224,7 +224,7 @@ fn edges(sizes: &[f64]) -> Vec<f64> {
 }
 
 /// A cell's text as drawn: its margins, anchor and direction, plus the table style's text colour and bold.
-pub(crate) fn cell_body(rctx: &Ctx, t: &Table, r: usize, c: usize, cell: &Cell) -> TextBody {
+pub fn cell_body(rctx: &Ctx, t: &Table, r: usize, c: usize, cell: &Cell) -> TextBody {
     let lk = look(rctx, t, r, c);
     let mut body = cell.text.clone();
     let [ml, mr, mt, mb] = cell.margins.unwrap_or([7.2, 7.2, 3.6, 3.6]);

crates/ui-egui/src/canvas.rs

@@ -528,6 +528,17 @@ fn overlays(app: &mut SlideApp, ui: &Ui, painter: &egui::Painter, xf: Xf, t: &To
         let a = x.affine();
         let pts = [Point::new(x0, y0), Point::new(x0 + w, y0), Point::new(x0 + w, y0 + h), Point::new(x0, y0 + h)].map(|q| xf.to_screen(a * q));
         poly(painter, pts, Stroke::new(2.0, t.accent));
+        // The composition is in the cell text; underline it where that text is drawn (#101).
+        for (a, b, thick) in deckcraft_engine::cmd::text::composition_underlines(st) {
+            painter.line_segment([xf.to_screen(a), xf.to_screen(b)], Stroke::new(if thick { 2.0 } else { 1.0 }, t.caret));
+        }
+        if !ts.is_range() {
+            let blink = (ui.input(|i| i.time) * 1.6).fract() < 0.6;
+            ui.ctx().request_repaint_after(std::time::Duration::from_millis(300));
+            if blink && let Some((top, bot)) = deckcraft_engine::cmd::text::caret_line(st, ts) {
+                painter.line_segment([xf.to_screen(top), xf.to_screen(bot)], Stroke::new(1.5, t.caret));
+            }
+        }
     }
     // Smart guides, marquee, previews.
     for g in &app.session.tool.guides {

docs/gaps.md

@@ -1,6 +1,6 @@
 # Where DeckCraft falls short of PowerPoint
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-13 · **Change:** minor (3-D bevel, camera and face lighting rendered; previous: minor, IME composition and CJK interface text landed, #101; previous: minor, core-workflow alpha gate added; stage stays alpha; before that: major, first itemized gap list; full re-measure against PowerPoint for Mac 16.113.4 and the open GitHub issues) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-14 · **Last updated:** 2026-10-14 · **Change:** minor (IME composition in a table cell is underlined; previous: minor, 3-D bevel, camera and face lighting rendered; previous: minor, IME composition and CJK interface text landed, #101) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 Every known shortfall, one entry each, ranked by how much it stops someone who presents with
 PowerPoint from switching. This is the work list: pick from the top. Numbers are summarized in
@@ -230,7 +230,6 @@ Detail in [localization-parity.md](localization-parity.md).
   (Noto CJK is excluded by the asset policy), so the web build draws Korean file names, notes and
   outline text as boxes; desktop borrows Malgun Gothic, Apple SD Gothic Neo or Noto Sans CJK.
   Adding an openly licensed Korean face (e.g. Nanum Gothic, OFL) to craft-fonts: 1–2 h.
-- **Table cells don't underline an IME composition** (the text is composed in place, #101). 1 h.
 - **UI isn't mirrored for right-to-left languages.** 6–10 h.
 - **Browser build draws Arabic and Hebrew as missing-glyph boxes in exports** (#81). 1–2 h.
 
@@ -256,6 +255,7 @@ Detail in [localization-parity.md](localization-parity.md).
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-14 | minor | An IME composition in a table cell is underlined in place, and the caret and candidate window sit in that cell |
 | 2026-10-13 | minor | Shape, picture and table rendering checked against PowerPoint on ~150 synthetic edge-case slides; 3-D bevels, cameras and face lighting now render approximately (gap narrowed to extrusion, rigs and the 3-D pane) |
 | 2026-10-12 | minor | IME composition in slide text and notes, and CJK interface text with real glyphs (#101): the IME gap is now Korean on the web and table-cell underlines |
 | 2026-10-12 | minor | EMF/WMF text, pattern and hatch brushes drawn; legacy OLE and ActiveX previews shown; the SVG gap keeps only EMF clip regions |

docs/localization-parity.md

@@ -1,6 +1,6 @@
 # Localization parity with PowerPoint
 
-> **Last reviewed:** 2026-10-10 · **Last updated:** 2026-10-12 · **Change:** minor (IME composition and CJK interface text, #101; previous: major, created; string count measured from source, PowerPoint's localizations read from its bundle) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
+> **Last reviewed:** 2026-10-14 · **Last updated:** 2026-10-14 · **Change:** minor (IME composition underlined in table cells; previous: minor, IME composition and CJK interface text, #101; previous: major, created) · **Target:** Microsoft PowerPoint for Mac 16.113 (Microsoft 365)
 
 DeckCraft's interface is English only today: strings are literals in the UI and engine code, with
 no catalog and no language switch. Requests: #15 (follow the system language), #30 and PR #34
@@ -44,8 +44,9 @@ Polish, Russian, Slovak, Swedish, Thai, Turkish and Traditional Chinese.
 Per-language hours assume the infrastructure exists: **8–14 h** once for a string catalog (copy a
 sibling app's approach, e.g. EffectCraft's menu and panel catalogs), a language setting that follows
 the system (#15), plural and number formatting, and an `xtask` check that every key has a
-translation. IME composition landed with #101 (slide text, notes and text fields; one undo step
-per composition); the hours that included it are kept until the next re-measure.
+translation. IME composition landed with #101 (slide text, table cells, notes and text fields;
+one undo step per composition, underlined in place); the hours that included it are kept until
+the next re-measure.
 
 ## Proofing languages
 
@@ -57,5 +58,6 @@ common misspellings (`crates/engine/src/cmd/review.rs`); see [gaps.md](gaps.md#p
 
 | Date | Change | Summary |
 |---|---|---|
+| 2026-10-14 | minor | IME composition in a table cell is underlined in place; the candidate window sits on that cell's caret |
 | 2026-10-12 | minor | IME composition for Chinese, Japanese and Korean, and interface text in any installed script (#101) |
 | 2026-10-10 | major | Created: twelve-language table, ~1,050 UI strings measured, PowerPoint for Mac's 26 languages from its bundle |