fix(layout): a publication legend that fits exactly isn't said to overflow

crates/engine/src/cmd/layout.rs

@@ -1701,11 +1701,14 @@ fn publication(s: &mut Session, p: &Value) -> CmdResult {
         let (ix, iy, iw, ih) = (r.0 + pad, r.1 + pad, lw - 2.0 * pad, lh - 2.0 * pad);
         let bar_fit = if bar.is_some() { bar_h.min(ih) } else { 0.0 };
         let rows_h = (ih - bar_fit - if bar.is_some() { bar_part - bar_h } else { 0.0 }).max(0.0);
-        if ch > 0.0 && (cw > iw || ch > rows_h) {
+        // A box sized to its content, less the padding again, can come out a rounding error
+        // short of it: that still fits.
+        const FIT_MM: f64 = 1e-6;
+        if ch > 0.0 && (cw > iw + FIT_MM || ch > rows_h + FIT_MM) {
             warnings.push("the legend lists more than fits its corner: its last rows or the ends of long labels are left out".into());
         }
         // In a column the colorbar takes the column's width, as its rows do.
-        if bar.is_some() && ((bar_w > iw && !legend_in_column) || bar_h > ih) {
+        if bar.is_some() && ((bar_w > iw + FIT_MM && !legend_in_column) || bar_h > ih + FIT_MM) {
             warnings.push("the legend's box is smaller than the colorbar: it is drawn narrower or shorter".into());
         }
         if ch > 0.0 && rows_h >= 1.0 {

crates/engine/src/tests.rs

@@ -3183,6 +3183,29 @@ fn publication_surrounds_keep_off_the_data() {
     let _ = std::fs::remove_dir_all(&dir);
 }
 
+/// A publication legend sized to its rows fits them: its box, less the padding, may come out a
+/// rounding error short of the rows' width, which isn't "more than fits" (macOS CI, whose fonts
+/// gave one such width). Layer names of many widths, so some land on a rounding error with any font.
+#[test]
+fn a_publication_legend_sized_to_its_rows_fits_them() {
+    let dir = std::env::temp_dir().join(format!("rustgis-legend-fit-{}", std::process::id()));
+    std::fs::create_dir_all(&dir).unwrap();
+    let names: Vec<String> = (0..300).map(|i| format!("{}{i}", &"WmilQxkaRb"[i % 10..])).collect();
+    for name in &names {
+        let path = dir.join(format!("{name}.geojson"));
+        std::fs::write(
+            &path,
+            r#"{"type": "FeatureCollection", "features": [{"type": "Feature", "properties": {}, "geometry": {"type": "Polygon", "coordinates": [[[4,4],[6,4],[6,6],[4,6],[4,4]]]}}]}"#,
+        )
+        .unwrap();
+        let mut s = Session::new(Project::default());
+        s.run("layer.addData", &json!({"path": path.display().to_string()})).unwrap();
+        let r = s.run("layout.publication", &json!({"extent": [0, 0, 10, 10], "author": ""})).unwrap();
+        assert!(!r["warnings"].to_string().contains("more than fits"), "{name}: {r}");
+    }
+    let _ = std::fs::remove_dir_all(&dir);
+}
+
 /// A publication layout keys a raster theme with a colorbar: the topmost visible raster drawn on a
 /// ramp gets one at the bottom of the legend's box; a map of vectors only gets none.
 #[test]