From 903bbb096d874a5bd0f27cb324129a2a92c8d42b Mon Sep 17 00:00:00 2001
From: lloyd <34131158+LloydNicholson@users.noreply.github.com>
Date: Fri, 9 Oct 2026 17:23:15 +0200
Subject: [PATCH] Issue #51: General numbers fit by the cell's own font, not
 11pt

grid.rs measured the digit width once, for an 11pt cell font, and
display_text judged how many General digits fit from that whatever the
cell's size. 9pt marks such as 100 in columns with a stored width of 4
(common in mark sheets) came out as ##. The width is now measured per cell
with its own font and size, as print.rs already does; the shared 11pt
measurement and its paint_quadrant parameter go away.

Test: a 9pt 100 in a 28px column draws in full, while 123456789 next to it
still shows ####. Fails before the fix.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
---
 crates/ui-egui/src/grid.rs          | 18 ++++--------------
 crates/ui-egui/tests/interaction.rs | 23 +++++++++++++++++++++++
 2 files changed, 27 insertions(+), 14 deletions(-)

diff --git a/crates/ui-egui/src/grid.rs b/crates/ui-egui/src/grid.rs
index 4b326cc36..30e849333 100644
--- a/crates/ui-egui/src/grid.rs
+++ b/crates/ui-egui/src/grid.rs
@@ -373,7 +373,6 @@ pub fn show(app: &mut SheetApp, ui: &mut egui::Ui) {
     let painter = ui.painter_at(rect);
     painter.rect_filled(rect, 0.0, t.grid_bg);
     let mut cf = CfCache::new();
-    let char_w = ui.fonts_mut(|f| f.glyph_width(&FontId::new(11.0 * 96.0 / 72.0 * geo.z, egui::FontFamily::Name(theme::CELL.into())), '0')).max(1.0);
     // Quadrants: (rows, cols, clip).
     let (sr0, sr1) = geo.scroll_rows(sh);
     let (sc0, sc1) = geo.scroll_cols(sh);
@@ -395,7 +394,7 @@ pub fn show(app: &mut SheetApp, ui: &mut egui::Ui) {
             continue;
         }
         let p = painter.with_clip_rect(*clip);
-        paint_quadrant(&p, &geo, &wb, si, sh, *rows, *cols, char_w, &mut cf, &t);
+        paint_quadrant(&p, &geo, &wb, si, sh, *rows, *cols, &mut cf, &t);
         paint_selection(&p, &geo, sh, &sel, &t, app);
     }
     // Freeze lines.
@@ -431,18 +430,7 @@ pub fn show(app: &mut SheetApp, ui: &mut egui::Ui) {
 }
 
 #[allow(clippy::too_many_arguments)]
-fn paint_quadrant(
-    p: &Painter,
-    geo: &Geo,
-    wb: &Workbook,
-    si: usize,
-    sh: &Sheet,
-    rows: (u32, u32),
-    cols: (u32, u32),
-    char_w: f32,
-    cf: &mut CfCache,
-    t: &Tokens,
-) {
+fn paint_quadrant(p: &Painter, geo: &Geo, wb: &Workbook, si: usize, sh: &Sheet, rows: (u32, u32), cols: (u32, u32), cf: &mut CfCache, t: &Tokens) {
     let z = geo.z;
     let (r0, r1) = rows;
     let (c0, c1) = cols;
@@ -560,6 +548,8 @@ fn paint_quadrant(
         let size = st.font.size * 96.0 / 72.0 * z;
         let fam = theme::cell_family(&st.font.name, st.font.bold, st.font.italic);
         let font = FontId::new(size, fam);
+        // Digits fit by the cell's own font and size, not the default 11pt (9pt marks in narrow columns).
+        let char_w = p.layout_no_wrap("0".to_string(), font.clone(), Color32::PLACEHOLDER).size().x.max(1.0);
         let avail_w = rect.right() - text_left;
         let (text, ncolor, numeric, fill_char) = display_text(wb, sh, c, &v, st, avail_w / z.max(0.1) * z, char_w);
         if text.is_empty() {
diff --git a/crates/ui-egui/tests/interaction.rs b/crates/ui-egui/tests/interaction.rs
index 74bbeb495..730cdae23 100644
--- a/crates/ui-egui/tests/interaction.rs
+++ b/crates/ui-egui/tests/interaction.rs
@@ -146,3 +146,26 @@ fn column_autocomplete_completes_on_enter() {
     key(&mut h, Key::Enter, Modifiers::NONE);
     assert_eq!(value(&h, "A5"), Value::from("Ea"));
 }
+
+#[test]
+fn general_numbers_fit_by_the_cells_own_font() {
+    // 9pt marks in narrow columns (a stored width of 4, i.e. 28px; common in mark sheets): "100" fits.
+    let mut s = blank();
+    s.execute("range.setValues", json!({"range": "A1", "values": [[100, 123456789]]})).unwrap();
+    s.execute("home.fontSize", json!({"range": "A1:B1", "size": 9})).unwrap();
+    s.execute("home.columnWidth", json!({"cols": "A:B", "width": 28})).unwrap();
+    s.execute("selection.set", json!({"cell": "C3"})).unwrap();
+    let h = harness(s);
+    let texts: Vec<String> = h
+        .output()
+        .shapes
+        .iter()
+        .filter_map(|c| match &c.shape {
+            egui::Shape::Text(t) => Some(t.galley.job.text.clone()),
+            _ => None,
+        })
+        .collect();
+    assert!(texts.iter().any(|t| t == "100"), "100 drawn in full: {texts:?}");
+    // A number that really doesn't fit still shows #### (once: only B1).
+    assert_eq!(texts.iter().filter(|t| t.starts_with('#')).count(), 1, "{texts:?}");
+}