Lottie: import a layer's time stretch below 1 % as 100 %, with a warning

crates/lottie/src/import.rs

@@ -399,7 +399,14 @@ fn build_layers(cx: &mut Ctx, project: &mut Project, comp: &mut Comp, layers: &[
         l.in_point = tb.tick(ip);
         l.out_point = tb.tick(op.max(ip));
         l.start_time = tb.tick(f(j, "st").unwrap_or(0.0));
-        l.stretch = f(j, "sr").unwrap_or(1.0) * 100.0;
+        // Below 1 % (or 0) the layer time divides by ~0, and layer.timeStretch refuses it too.
+        let sr = f(j, "sr").unwrap_or(1.0);
+        l.stretch = if sr.is_finite() && sr.abs() >= 0.01 {
+            sr * 100.0
+        } else {
+            cx.im.warn(format!("{name}: a time stretch of {} % is not supported (100 % used)", sr * 100.0));
+            100.0
+        };
         if j.get("ddd").and_then(Json::as_u64) == Some(1) {
             l.switches.three_d = true;
         }

crates/lottie/src/tests.rs

@@ -484,6 +484,18 @@ fn layers_parenting_timing_mattes_masks_and_blend_modes() {
     compare_renders(&p, cid, &q, nc, 2.0 / 255.0);
 }
 
+#[test]
+fn zero_time_stretch_is_not_imported() {
+    let doc = json!({"w": 20, "h": 20, "fr": 30, "ip": 0, "op": 30, "assets": [],
+        "layers": [{"ty": 1, "ind": 1, "sc": "#ff0000", "sw": 20, "sh": 20, "sr": 0, "ip": 0, "op": 30, "st": 0, "ks": {}}]});
+    let mut q = Project::default();
+    let imp = import(&mut q, doc.to_string().as_bytes(), "Imported", "", &mut |_| None).unwrap();
+    let l = &q.comp(imp.comp).unwrap().layers[0];
+    // layer.timeStretch refuses anything below 1 %, and keyframe commands refuse a layer with 0 %.
+    assert_eq!(l.stretch, 100.0);
+    assert!(imp.warnings.iter().any(|w| w.contains("time stretch")), "{:?}", imp.warnings);
+}
+
 #[test]
 fn precomp_with_time_remap() {
     let (mut p, cid) = setup();