lottie/parser: Fixed regression of interpolator string handling.

With older bodymovin pluggins the interpolator cache string sometimes
dosen't match with the in and out tangent results into wrong animation.
So parse the interpolator string whenever available.

src/lottie/lottieparser.cpp

@@ -260,7 +260,7 @@ public:
     void parseShapeProperty(LOTAnimatable<LottieShapeData> &obj);
     void parseDashProperty(LOTDashProperty &dash);
 
-    std::shared_ptr<VInterpolator> interpolator(VPointF inTangent, VPointF outTangent);
+    std::shared_ptr<VInterpolator> interpolator(VPointF, VPointF, std::string);
 
     LottieColor toColor(const char *str);
 
@@ -1840,20 +1840,21 @@ bool LottieParserImpl::parseKeyFrameValue(const char * key,
 }
 
 std::shared_ptr<VInterpolator>
-LottieParserImpl::interpolator(VPointF inTangent, VPointF outTangent)
+LottieParserImpl::interpolator(VPointF inTangent, VPointF outTangent, std::string key)
 {
-    std::array<char, 20> temp;
+    if (key.empty()) {
-    snprintf(temp.data(), temp.size(), "%.2f_%.2f_%.2f_%.2f",
+        std::array<char, 20> temp;
-             inTangent.x(), inTangent.y(), outTangent.x(), outTangent.y());
+        snprintf(temp.data(), temp.size(), "%.2f_%.2f_%.2f_%.2f",
-
+                 inTangent.x(), inTangent.y(), outTangent.x(), outTangent.y());
-    std::string key(temp.data());
+        key = temp.data();
+    }
 
     auto search = mInterpolatorCache.find(key);
     if (search != mInterpolatorCache.end()) {
         return search->second;
     } else {
         auto obj = std::make_shared<VInterpolator>(VInterpolator(outTangent, inTangent));
-        mInterpolatorCache[key] =  obj;
+        mInterpolatorCache[std::move(key)] =  obj;
         return obj;
     }
 }
@@ -1865,6 +1866,7 @@ template <typename T>
 void LottieParserImpl::parseKeyFrame(LOTAnimInfo<T> &obj)
 {
     struct ParsedField {
+        std::string interpolatorKey;
         bool interpolator{false};
         bool value{false};
         bool hold{false};
@@ -1893,6 +1895,23 @@ void LottieParserImpl::parseKeyFrame(LOTAnimInfo<T> &obj)
             parsed.noEndValue = false;
             getValue(keyframe.mValue.mEndValue);
             continue;
+        } else if (0 == strcmp(key, "n")) {
+            if (PeekType() == kStringType) {
+                parsed.interpolatorKey = GetString();
+            } else {
+                RAPIDJSON_ASSERT(PeekType() == kArrayType);
+                EnterArray();
+                while (NextArrayValue()) {
+                    RAPIDJSON_ASSERT(PeekType() == kStringType);
+                    if (parsed.interpolatorKey.empty()) {
+                        parsed.interpolatorKey = GetString();
+                    } else {
+                        //skip rest of the string
+                        GetString();
+                    }
+                }
+            }
+            continue;
         } else if (parseKeyFrameValue(key, keyframe.mValue)) {
             continue;
         } else if (0 == strcmp(key, "h")) {
@@ -1921,7 +1940,7 @@ void LottieParserImpl::parseKeyFrame(LOTAnimInfo<T> &obj)
         keyframe.mEndFrame = keyframe.mStartFrame;
         obj.mKeyFrames.push_back(keyframe);
     } else if (parsed.interpolator) {
-        keyframe.mInterpolator = interpolator(inTangent, outTangent);
+        keyframe.mInterpolator = interpolator(inTangent, outTangent, std::move(parsed.interpolatorKey));
         obj.mKeyFrames.push_back(keyframe);
     } else {
         //its the last frame discard.