3 files changed, 61 insertions, 8 deletions

diff --git a/experimental/skottie/Skottie.cpp b/experimental/skottie/Skottie.cpp
index a7b6b23817..5a04e5a719 100644
--- a/experimental/skottie/Skottie.cpp
+++ b/experimental/skottie/Skottie.cpp
@@ -427,19 +427,21 @@ std::vector<sk_sp<sksg::GeometryNode>> AttachTrimGeometryEffect(
     std::vector<sk_sp<sksg::GeometryNode>> trimmed;
     trimmed.reserve(inputs.size());
     for (const auto& i : inputs) {
-        const auto trim = sksg::TrimEffect::Make(i);
-        trimmed.push_back(trim);
+        const auto trimEffect = sksg::TrimEffect::Make(i);
+        trimmed.push_back(trimEffect);
+
+        const auto trimComposite = sk_make_sp<CompositeTrimEffect>(std::move(trimEffect));
         BindProperty<ScalarValue>(jtrim["s"], &ctx->fAnimators,
-            [trim](const ScalarValue& s) {
-                trim->setStart(s * 0.01f);
+            [trimComposite](const ScalarValue& s) {
+                trimComposite->setStart(s);
             });
         BindProperty<ScalarValue>(jtrim["e"], &ctx->fAnimators,
-            [trim](const ScalarValue& e) {
-                trim->setEnd(e * 0.01f);
+            [trimComposite](const ScalarValue& e) {
+                trimComposite->setEnd(e);
             });
         BindProperty<ScalarValue>(jtrim["o"], &ctx->fAnimators,
-            [trim](const ScalarValue& o) {
-                trim->setOffset(o / 360);
+            [trimComposite](const ScalarValue& o) {
+                trimComposite->setOffset(o);
             });
     }
 
diff --git a/experimental/skottie/SkottieProperties.cpp b/experimental/skottie/SkottieProperties.cpp
index 0816e15bca..a774217a8c 100644
--- a/experimental/skottie/SkottieProperties.cpp
+++ b/experimental/skottie/SkottieProperties.cpp
@@ -15,6 +15,7 @@
 #include "SkSGPath.h"
 #include "SkSGRect.h"
 #include "SkSGTransform.h"
+#include "SkSGTrimEffect.h"
 
 #include <cmath>
 
@@ -190,4 +191,37 @@ void CompositeRadialGradient::onApply() {
     grad->setEndRadius(SkPoint::Distance(this->startPoint(), this->endPoint()));
 }
 
+CompositeTrimEffect::CompositeTrimEffect(sk_sp<sksg::TrimEffect> trimEffect)
+    : fTrimEffect(std::move(trimEffect)) {
+    SkASSERT(fTrimEffect);
+}
+
+void CompositeTrimEffect::apply() {
+    // BM semantics: start/end are percentages, offset is "degrees" (?!).
+    const auto  start = fStart  / 100,
+                  end = fEnd    / 100,
+               offset = fOffset / 360;
+
+    auto startT = SkTMin(start, end) + offset,
+          stopT = SkTMax(start, end) + offset;
+    auto   mode = SkTrimPathEffect::Mode::kNormal;
+
+    if (stopT - startT < 1) {
+        startT -= SkScalarFloorToScalar(startT);
+        stopT  -= SkScalarFloorToScalar(stopT);
+
+        if (startT > stopT) {
+            SkTSwap(startT, stopT);
+            mode = SkTrimPathEffect::Mode::kInverted;
+        }
+    } else {
+        startT = 0;
+        stopT  = 1;
+    }
+
+    fTrimEffect->setStart(startT);
+    fTrimEffect->setStop(stopT);
+    fTrimEffect->setMode(mode);
+}
+
 } // namespace skottie
diff --git a/experimental/skottie/SkottieProperties.h b/experimental/skottie/SkottieProperties.h
index 8ca026eaeb..5e3fad0d9a 100644
--- a/experimental/skottie/SkottieProperties.h
+++ b/experimental/skottie/SkottieProperties.h
@@ -28,6 +28,7 @@ class Path;
 class RadialGradient;
 class RRect;
 class RenderNode;;
+class TrimEffect;
 }
 
 namespace Json { class Value; }
@@ -161,6 +162,22 @@ private:
     using INHERITED = CompositeGradient;
 };
 
+class CompositeTrimEffect final : public SkRefCnt {
+public:
+    explicit CompositeTrimEffect(sk_sp<sksg::TrimEffect>);
+
+    COMPOSITE_PROPERTY(Start , SkScalar,   0)
+    COMPOSITE_PROPERTY(End   , SkScalar, 100)
+    COMPOSITE_PROPERTY(Offset, SkScalar,   0)
+
+private:
+    void apply();
+
+    sk_sp<sksg::TrimEffect> fTrimEffect;
+
+    using INHERITED = SkRefCnt;
+};
+
 #undef COMPOSITE_PROPERTY
 
 } // namespace skottie