Print checkbox cells as boxes, not TRUE/FALSE (#2972)

A checkbox cell drew a box on screen but printed and exported to PDF
its value as TRUE or FALSE. The print path now draws the box as the
grid does: white with a grey outline when unchecked, green with a
white tick when checked. Other values in a checkbox cell still print
as text.

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

crates/engine/src/cmd/print/draw.rs

@@ -2,8 +2,8 @@ use super::layout::{DENSE_BLOCK, SheetLayout};
 use super::objects::draw_cell_picture;
 use super::text::{TextPlacement, draw_text};
 use super::{
-    BorderLine, BorderStyle, Borders, CellRef, Color, Font, Page, PatternType, Point, RangeRef, Rgb, Sheet, Style, StyleId, Underline, Workbook,
-    split_sheet,
+    BorderLine, BorderStyle, Borders, CellRef, Color, Font, Page, PatternType, Point, RangeRef, Rgb, Sheet, Style, StyleId, Underline, Value,
+    Workbook, split_sheet,
 };
 
 // ---------------------------------------------------------------- drawing
@@ -280,6 +280,7 @@ pub(super) fn draw_block(pg: &mut Page, b: &Block, gridlines: bool, cf: &mut Opt
                 || merges.iter().any(|m| m.start == *c)
                 || !sh.value(*c).is_empty()
                 || l.style.borders != Borders::default()
+                || l.style.num_fmt.as_str() == "checkbox"
         })
         .collect();
     let rect_of = |c: CellRef| -> (f32, f32, f32, f32, bool) {
@@ -343,6 +344,8 @@ pub(super) fn draw_block(pg: &mut Page, b: &Block, gridlines: bool, cf: &mut Opt
         }
         if let Some(picture) = sh.cell_pictures.get(c) {
             draw_cell_picture(pg, &picture.data, (x, y, w, h), b.k);
+        } else if let Some(on) = checkbox_state(l, &sh.value(*c)) {
+            draw_checkbox(pg, (x, y, w, h), b.k, on);
         } else {
             draw_text(pg, b, TextPlacement { cell: *c, look: l, rect: (x, y, w, h), merged, merges: &merges, limits: (bx, bx + bw) });
         }
@@ -350,6 +353,37 @@ pub(super) fn draw_block(pg: &mut Page, b: &Block, gridlines: bool, cf: &mut Opt
     pg.restore();
 }
 
+/// A checkbox cell prints TRUE/FALSE (and empty) as a box, as on screen (#2972); other values
+/// print as text.
+fn checkbox_state(l: &Look, v: &Value) -> Option<bool> {
+    if l.style.num_fmt.as_str() != "checkbox" || l.cf.as_ref().is_some_and(|cf| cf.hide_value) {
+        return None;
+    }
+    match v {
+        Value::Bool(on) => Some(*on),
+        Value::Empty => Some(false),
+        _ => None,
+    }
+}
+
+/// A checkbox centred in the cell: white with a grey outline, or green with a white tick.
+fn draw_checkbox(pg: &mut Page, (x, y, w, h): (f32, f32, f32, f32), k: f32, on: bool) {
+    let s = (13.2 * k).min(w - 2.0 * k).min(h - 2.0 * k);
+    if s <= 0.0 {
+        return;
+    }
+    let (bx, by) = (x + (w - s) / 2.0, y + (h - s) / 2.0);
+    let corners = [[bx, by], [bx + s, by], [bx + s, by + s], [bx, by + s]];
+    if on {
+        let green = [0x10, 0x7C, 0x41];
+        pg.polygon(&corners, Some(green), Some((green, 0.75 * k)));
+        let tick = [[bx + 0.22 * s, by + 0.52 * s], [bx + 0.42 * s, by + 0.72 * s], [bx + 0.78 * s, by + 0.30 * s]];
+        pg.polyline(&tick, 0.14 * s, [0xFF, 0xFF, 0xFF], &[]);
+    } else {
+        pg.polygon(&corners, Some([0xFF, 0xFF, 0xFF]), Some(([110, 110, 110], 0.75 * k)));
+    }
+}
+
 pub(super) struct PendingPdfLink {
     pub(super) page: usize,
     pub(super) sheet: usize,

crates/engine/src/cmd/print/tests.rs

@@ -565,3 +565,18 @@ fn rotated_wrapped_text_prints_rotated() {
     assert_eq!(up + down, blocks.len(), "a header line printed flat: {blocks:?}");
     assert!((1..=3).contains(&up) && (1..=3).contains(&down), "up {up}, down {down}: {blocks:?}");
 }
+
+#[test]
+fn checkbox_cells_print_as_boxes_not_true_false() {
+    // #2972: a checkbox cell printed its value as TRUE or FALSE.
+    let mut s = s();
+    s.execute("insert.checkbox", json!({"range": "A1:A2"})).unwrap();
+    s.execute("cell.toggleCheckbox", json!({"cell": "A2"})).unwrap();
+    s.execute("cell.set", json!({"cell": "C1", "input": "TRUE"})).unwrap();
+    let (pdf, _) = pdf_of(&mut s, json!({}));
+    assert!(!contains(&pdf, "(FALSE) Tj"), "the unchecked box printed as FALSE");
+    // Only the plain TRUE in C1 prints as text; the checked box is a filled box.
+    let text = String::from_utf8_lossy(&pdf);
+    assert_eq!(text.matches("(TRUE) Tj").count(), 1, "the checked box printed as TRUE");
+    assert!(contains(&pdf, "0.063 0.486 0.255 rg"), "the checked box is not filled");
+}