lottie: clamp playback to last frame

Clamp fractional frame values at the final valid frame instead of only
clamping values at the exclusive out point.

This prevents playback from advancing past the last frame and then
jumping backward when progress reaches the animation endpoint.

rename the inFrame, outFrame -> inPoint, outPoint to align with
the lottie spec.

Author: hermet

src/loaders/lottie/tvgLottieBuilder.cpp

@@ -981,7 +981,7 @@ void LottieBuilder::updateImage(LottieLayer* layer, float frameNo)
     }
 
     layer->scene->add(picture->refCnt() == 1 ? picture : picture->duplicate());
-    image->play((frameNo - layer->inFrame) / (layer->outFrame - layer->inFrame));
+    image->play((frameNo - layer->inPoint) / (layer->outPoint - layer->inPoint));
 }
 
 
@@ -1547,7 +1547,7 @@ void LottieBuilder::updateLayer(LottieComposition* comp, Scene* scene, LottieLay
     layer->scene = nullptr;
 
     //visibility
-    if (frameNo < layer->inFrame || frameNo >= layer->outFrame) {
+    if (frameNo < layer->inPoint || frameNo >= layer->outPoint) {
         layer->invalidate();
         return;
     }
@@ -1722,13 +1722,13 @@ void LottieBuilder::updateAudio(LottieComposition* comp, LottieLayer* layer, flo
     if (layer->children.empty()) return;
 
     auto ctrl = layer->audio();
-    auto active = frameNo >= layer->inFrame && frameNo < layer->outFrame;
+    auto active = frameNo >= layer->inPoint && frameNo < layer->outPoint;
     auto volume = active ? ctrl->volume(frameNo, tween, exps) : 100.0f;
 
     // audio condition is changed
     if ((active != ctrl->prevActive) || (active && !tvg::equal(volume, ctrl->prevVolume))) {
         auto& src = static_cast<LottieAudio*>(layer->children.first())->src;
-        auto offset = active ? (layer->remap(comp, frameNo, exps) - layer->remap(comp, layer->inFrame, exps)) / comp->frameRate : 0.0f;
+        auto offset = active ? (layer->remap(comp, frameNo, exps) - layer->remap(comp, layer->inPoint, exps)) / comp->frameRate : 0.0f;
         LottieAudioResolver info = {src.data, src.mimeType, src.size, offset, volume, active, (src.size > 0)};
         audioResolver.func(info, audioResolver.data);
     }

src/loaders/lottie/tvgLottieExpressions.cpp

@@ -489,11 +489,11 @@ static void _buildLayer(jerry_value_t context, float frameNo, LottieLayer* layer
     jerry_object_set_sz(context, "hasParent", hasParent);
     jerry_value_free(hasParent);
 
-    auto inPoint = jerry_number(layer->inFrame / exp->comp->frameRate);
+    auto inPoint = jerry_number(layer->inPoint / exp->comp->frameRate);
     jerry_object_set_sz(context, "inPoint", inPoint);
     jerry_value_free(inPoint);
 
-    auto outPoint = jerry_number(layer->outFrame / exp->comp->frameRate);
+    auto outPoint = jerry_number(layer->outPoint / exp->comp->frameRate);
     jerry_object_set_sz(context, "outPoint", outPoint);
     jerry_value_free(outPoint);
 
@@ -1127,7 +1127,7 @@ static jerry_value_t _loopOut(const jerry_call_info_t* info, const jerry_value_t
     auto data = static_cast<ExpContent*>(jerry_object_get_native_ptr(info->function, &freeCb));
     auto mode = static_cast<LottieProperty::Loop>((int) _loopCommon(args, argsCnt) + LOOP_OUT_OFFSET);
     auto key = (argsCnt > 1) ? jerry_value_as_int32(args[1]) : 0;
-    return _buildValue(data->exp->property->loop(data->frameNo, key, mode, data->exp->layer->outFrame), data->exp->property);
+    return _buildValue(data->exp->property->loop(data->frameNo, key, mode, data->exp->layer->outPoint), data->exp->property);
 }
 
 
@@ -1145,7 +1145,7 @@ static jerry_value_t _loopIn(const jerry_call_info_t* info, const jerry_value_t
     auto data = static_cast<ExpContent*>(jerry_object_get_native_ptr(info->function, &freeCb));
     auto mode = _loopCommon(args, argsCnt);
     auto key = (argsCnt > 1) ? jerry_value_as_int32(args[1]) : 0;
-    return _buildValue(data->exp->property->loop(data->frameNo, key, mode, data->exp->layer->outFrame), data->exp->property);
+    return _buildValue(data->exp->property->loop(data->frameNo, key, mode, data->exp->layer->outPoint), data->exp->property);
 }
 
 
@@ -1418,11 +1418,11 @@ void LottieExpressions::buildGlobal(Context& context, float frameNo, LottieExpre
     jerry_object_set_sz(context.global, EXP_INDEX, index);
     jerry_value_free(index);
 
-    auto inPoint = jerry_number(exp->layer->inFrame / exp->comp->frameRate);
+    auto inPoint = jerry_number(exp->layer->inPoint / exp->comp->frameRate);
     jerry_object_set_sz(context.global, "inPoint", inPoint);
     jerry_value_free(inPoint);
 
-    auto outPoint = jerry_number(exp->layer->outFrame / exp->comp->frameRate);
+    auto outPoint = jerry_number(exp->layer->outPoint / exp->comp->frameRate);
     jerry_object_set_sz(context.global, "outPoint", outPoint);
     jerry_value_free(outPoint);
 }

src/loaders/lottie/tvgLottieModel.h

@@ -1047,8 +1047,8 @@ struct LottieRootLayer : LottieGroup
 
     float timeStretch = 1.0f;
     float w = 0.0f, h = 0.0f;
-    float inFrame = 0.0f;
-    float outFrame = 0.0f;
+    float inPoint = 0.0f;   // frame when the layer becomes visible
+    float outPoint = 0.0f;  // frame when the layer becomes invisible
     float startFrame = 0.0f;
 
     bool effect = false;  // true if any effect is activated in its tree
@@ -1195,12 +1195,12 @@ struct LottieComposition
 
     float timeAtFrame(float frameNo)
     {
-        return (frameNo - root->inFrame) / frameRate;
+        return (frameNo - root->inPoint) / frameRate;
     }
 
     float frameCnt() const
     {
-        return root->outFrame - root->inFrame;
+        return root->outPoint - root->inPoint;
     }
 
     LottieLayer* asset(unsigned long id)
@@ -1214,9 +1214,9 @@ struct LottieComposition
 
     void clamp(float& frameNo)
     {
-        frameNo += root->inFrame;
-        if (frameNo < root->inFrame) frameNo = root->inFrame;
-        if (frameNo >= root->outFrame) frameNo = root->outFrame - 1;
+        frameNo += root->inPoint;
+        if (frameNo < root->inPoint) frameNo = root->inPoint;
+        if (frameNo > root->outPoint - 1.0f) frameNo = root->outPoint - 1.0f;
     }
 
     LottieRootLayer* root = nullptr;

src/loaders/lottie/tvgLottieParser.cpp

@@ -1595,8 +1595,8 @@ LottieLayer* LottieParser::parseLayer(LottieRootLayer* precomp)
         }
         else if (KEY_AS("ao")) layer->autoOrient = getInt();
         else if (KEY_AS("shapes")) parseShapes(layer->children);
-        else if (KEY_AS("ip")) layer->inFrame = getFloat();
-        else if (KEY_AS("op")) layer->outFrame = getFloat();
+        else if (KEY_AS("ip")) layer->inPoint = getFloat();
+        else if (KEY_AS("op")) layer->outPoint = getFloat();
         else if (KEY_AS("st")) layer->startFrame = getFloat();
         else if (KEY_AS("bm")) layer->blendMethod = (BlendMethod) getInt();
         else if (KEY_AS("parent")) layer->pix = getInt();
@@ -1792,14 +1792,14 @@ bool LottieParser::parse()
 
     Array<LottieGlyph*> glyphs;
 
-    auto startFrame = 0.0f;
-    auto endFrame = 0.0f;
+    auto inPoint = 0.0f;
+    auto outPoint = 0.0f;
 
     while (auto key = nextObjectKey()) {
         if (KEY_AS("v")) comp->version = getStringCopy();
         else if (KEY_AS("fr")) comp->frameRate = getFloat();
-        else if (KEY_AS("ip")) startFrame = getFloat();
-        else if (KEY_AS("op")) endFrame = getFloat();
+        else if (KEY_AS("ip")) inPoint = getFloat();
+        else if (KEY_AS("op")) outPoint = getFloat();
         else if (KEY_AS("w")) comp->w = getFloat();
         else if (KEY_AS("h")) comp->h = getFloat();
         else if (KEY_AS("nm")) comp->name = getStringCopy();
@@ -1817,8 +1817,8 @@ bool LottieParser::parse()
         return false;
     }
 
-    comp->root->inFrame = startFrame;
-    comp->root->outFrame = endFrame;
+    comp->root->inPoint = inPoint;
+    comp->root->outPoint = outPoint;
 
     postProcess(glyphs);