From 6a15d7487fdf5c79e5f11be85cc74cddbd46d813 Mon Sep 17 00:00:00 2001
From: Ishan Khot <ishankhot@fb.com>
Date: Wed, 20 May 2020 16:31:18 -0700
Subject: [PATCH] Revert D21587648: LayoutImplementations: implement all
 existing animation curves besides Keyboard

Differential Revision:
D21587648

Original commit changeset: 246ab7fd4039

fbshipit-source-id: 427e13ff821776feb4952c3438c15ea815fce5f0
---
 ReactCommon/fabric/animations/BUCK            |  1 -
 .../LayoutAnimationKeyFrameManager.cpp        | 53 +++----------------
 2 files changed, 8 insertions(+), 46 deletions(-)

diff --git a/ReactCommon/fabric/animations/BUCK b/ReactCommon/fabric/animations/BUCK
index 123fb6c45e2..fde3bc7decd 100644
--- a/ReactCommon/fabric/animations/BUCK
+++ b/ReactCommon/fabric/animations/BUCK
@@ -36,7 +36,6 @@ rn_xplat_cxx_library(
         "-frtti",
         "-std=c++14",
         "-Wall",
-        "-lm",
     ],
     fbobjc_compiler_flags = APPLE_COMPILER_FLAGS,
     fbobjc_preprocessor_flags = get_preprocessor_flags_for_build_mode() + get_apple_inspector_flags(),
diff --git a/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp b/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp
index 034d871388b..4f617bf71f5 100644
--- a/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp
+++ b/ReactCommon/fabric/animations/LayoutAnimationKeyFrameManager.cpp
@@ -105,7 +105,7 @@ static better::optional<AnimationConfig> parseAnimationConfig(
 
   double duration = defaultDuration;
   double delay = 0;
-  double springDamping = 0.5;
+  double springDamping = 0;
   double initialVelocity = 0;
 
   auto const durationIt = config.find("duration");
@@ -236,50 +236,13 @@ LayoutAnimationKeyFrameManager::calculateAnimationProgress(
   uint64_t startTime = animation.startTime;
   uint64_t delay = mutationConfig.delay;
   uint64_t endTime = startTime + delay + mutationConfig.duration;
-
-  static const float PI = 3.14159265358979323846;
-
-  if (now >= endTime) {
-    return {1, 1};
-  }
-  if (now < startTime + delay) {
-    return {0, 0};
-  }
-
-  double linearTimeProgression = 1 -
-      (double)(endTime - delay - now) / (double)(endTime - animation.startTime);
-
-  if (mutationConfig.animationType == AnimationType::Linear) {
-    return {linearTimeProgression, linearTimeProgression};
-  } else if (mutationConfig.animationType == AnimationType::EaseIn) {
-    // This is an accelerator-style interpolator.
-    // In the future, this parameter (2.0) could be adjusted. This has been the
-    // default for Classic RN forever.
-    return {linearTimeProgression, pow(linearTimeProgression, 2.0)};
-  } else if (mutationConfig.animationType == AnimationType::EaseOut) {
-    // This is an decelerator-style interpolator.
-    // In the future, this parameter (2.0) could be adjusted. This has been the
-    // default for Classic RN forever.
-    return {linearTimeProgression, 1.0 - pow(1 - linearTimeProgression, 2.0)};
-  } else if (mutationConfig.animationType == AnimationType::EaseInEaseOut) {
-    // This is a combination of accelerate+decelerate.
-    // The animation starts and ends slowly, and speeds up in the middle.
-    return {linearTimeProgression,
-            cos((linearTimeProgression + 1.0) * PI) / 2 + 0.5};
-  } else if (mutationConfig.animationType == AnimationType::Spring) {
-    // Using mSpringDamping in this equation is not really the exact
-    // mathematical springDamping, but a good approximation We need to replace
-    // this equation with the right Factor that accounts for damping and
-    // friction
-    double damping = mutationConfig.springDamping;
-    return {
-        linearTimeProgression,
-        (1 +
-         pow(2, -10 * linearTimeProgression) *
-             sin((linearTimeProgression - damping / 4) * PI * 2 / damping))};
-  } else {
-    return {linearTimeProgression, linearTimeProgression};
-  }
+  double progress = (now >= endTime)
+      ? 1
+      : ((now < startTime + delay) ? 0
+                                   : 1 -
+                 (double)(endTime - delay - now) /
+                     (double)(endTime - animation.startTime));
+  return {progress, progress};
 }
 
 void LayoutAnimationKeyFrameManager::adjustDelayedMutationIndicesForMutation(