Lottie: warn when embedded glyphs (chars) are not imported

A Lottie file can carry glyph outlines in `chars` for players that lack
the fonts. The import drops them and sets the text in installed fonts,
which can draw it in a fallback font. It now says so in the warnings,
naming the font families the glyphs were for.

Fixes #2844.

crates/lottie/src/import.rs

@@ -135,6 +135,17 @@ pub fn import(
             cx.fonts.push((n, fam, st));
         }
     }
+    // Glyph outlines embedded for players without the fonts. Text is set in installed fonts.
+    if let Some(chars) = doc.get("chars").and_then(Json::as_array).filter(|c| !c.is_empty()) {
+        let mut fams: Vec<&str> = vec![];
+        for fam in chars.iter().filter_map(|c| s(c, "fFamily")) {
+            if !fams.contains(&fam) {
+                fams.push(fam);
+            }
+        }
+        let of = if fams.is_empty() { String::new() } else { format!(" of {}", fams.join(", ")) };
+        cx.im.warn(format!("embedded glyphs (`chars`){of} are not imported; text uses the installed fonts"));
+    }
     let (w, h) = (w.round().max(1.0) as u32, h.round().max(1.0) as u32);
     let duration = tb.tick(op);
     // Pass 1: asset items (precomps empty for now, images stored).

crates/lottie/src/tests.rs

@@ -520,6 +520,17 @@ fn zero_time_stretch_is_not_imported() {
     assert!(imp.warnings.iter().any(|w| w.contains("time stretch")), "{:?}", imp.warnings);
 }
 
+#[test]
+fn embedded_glyphs_are_reported_when_dropped() {
+    let glyph = |ch: &str, fam: &str| json!({"ch": ch, "size": 100, "style": "Regular", "w": 60, "fFamily": fam, "data": {"shapes": []}});
+    let doc = json!({"w": 20, "h": 20, "fr": 30, "ip": 0, "op": 30, "assets": [], "layers": [],
+        "fonts": {"list": [{"fName": "Sans-Regular", "fFamily": "Sans", "fStyle": "Regular"}]},
+        "chars": [glyph("A", "Sans"), glyph("B", "Sans"), glyph("C", "Serif")]});
+    let mut q = Project::default();
+    let imp = import(&mut q, doc.to_string().as_bytes(), "Imported", "", &mut |_| None).unwrap();
+    assert_eq!(imp.warnings, ["embedded glyphs (`chars`) of Sans, Serif are not imported; text uses the installed fonts"]);
+}
+
 #[test]
 fn precomp_with_time_remap() {
     let (mut p, cid) = setup();