1 /* 2 * Copyright 2018 Google Inc. 3 * 4 * Use of this source code is governed by a BSD-style license that can be 5 * found in the LICENSE file. 6 */ 7 8 #include "SkottiePriv.h" 9 10 #include "SkJSON.h" 11 #include "SkottieJson.h" 12 #include "SkottieValue.h" 13 #include "SkMakeUnique.h" 14 #include "SkSGRenderNode.h" 15 #include "SkSGScene.h" 16 #include "SkTLazy.h" 17 18 namespace skottie { 19 namespace internal { 20 21 sk_sp<sksg::RenderNode> AnimationBuilder::attachPrecompLayer(const skjson::ObjectValue& jlayer, 22 const LayerInfo&, 23 AnimatorScope* ascope) const { 24 const skjson::ObjectValue* time_remap = jlayer["tm"]; 25 // Empirically, a time mapper supersedes start/stretch. 26 const auto start_time = time_remap ? 0.0f : ParseDefault<float>(jlayer["st"], 0.0f), 27 stretch_time = time_remap ? 1.0f : ParseDefault<float>(jlayer["sr"], 1.0f); 28 const auto requires_time_mapping = !SkScalarNearlyEqual(start_time , 0) || 29 !SkScalarNearlyEqual(stretch_time, 1) || 30 time_remap; 31 32 AnimatorScope local_animators; 33 auto precomp_layer = this->attachAssetRef(jlayer, 34 requires_time_mapping ? &local_animators : ascope, 35 [this] (const skjson::ObjectValue& jcomp, 36 AnimatorScope* ascope) { 37 return this->attachComposition(jcomp, ascope); 38 }); 39 40 // Applies a bias/scale/remap t-adjustment to child animators. 41 class CompTimeMapper final : public sksg::GroupAnimator { 42 public: 43 CompTimeMapper(sksg::AnimatorList&& layer_animators, float time_bias, float time_scale) 44 : INHERITED(std::move(layer_animators)) 45 , fTimeBias(time_bias) 46 , fTimeScale(time_scale) {} 47 48 void onTick(float t) override { 49 // When time remapping is active, |t| is driven externally. 50 if (fRemappedTime.isValid()) { 51 t = *fRemappedTime.get(); 52 } 53 54 this->INHERITED::onTick((t + fTimeBias) * fTimeScale); 55 } 56 57 void remapTime(float t) { fRemappedTime.set(t); } 58 59 private: 60 const float fTimeBias, 61 fTimeScale; 62 SkTLazy<float> fRemappedTime; 63 64 using INHERITED = sksg::GroupAnimator; 65 }; 66 67 if (requires_time_mapping) { 68 const auto t_bias = -start_time, 69 t_scale = sk_ieee_float_divide(1, stretch_time); 70 auto time_mapper = 71 skstd::make_unique<CompTimeMapper>(std::move(local_animators), t_bias, 72 sk_float_isfinite(t_scale) ? t_scale : 0); 73 if (time_remap) { 74 // The lambda below captures a raw pointer to the mapper object. That should be safe, 75 // because both the lambda and the mapper are scoped/owned by ctx->fAnimators. 76 auto* raw_mapper = time_mapper.get(); 77 auto frame_rate = fFrameRate; 78 this->bindProperty<ScalarValue>(*time_remap, ascope, 79 [raw_mapper, frame_rate](const ScalarValue& t) { 80 raw_mapper->remapTime(t * frame_rate); 81 }); 82 } 83 ascope->push_back(std::move(time_mapper)); 84 } 85 86 return precomp_layer; 87 } 88 89 } // namespace internal 90 } // namespace skottie 91
