Build ChatListUI

submodules/LegacyComponents/Sources/POPAnimationExtras.mm

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+/**
+ Copyright (c) 2014-present, Facebook, Inc.
+ All rights reserved.
+ 
+ This source code is licensed under the BSD-style license found in the
+ LICENSE file in the root directory of this source tree. An additional grant
+ of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "POPAnimationExtras.h"
+
+#import "POPAnimationPrivate.h"
+#import "POPMath.h"
+
+#if TARGET_OS_IPHONE
+#import <UIKit/UIKit.h>
+#endif
+
+#if TARGET_IPHONE_SIMULATOR
+UIKIT_EXTERN CGFloat UIAnimationDragCoefficient(); // UIKit private drag coeffient, use judiciously
+#endif
+
+CGFloat POPAnimationDragCoefficient()
+{
+#if TARGET_IPHONE_SIMULATOR
+  return UIAnimationDragCoefficient();
+#else
+  return 1.0;
+#endif
+}
+
+@implementation CAAnimation (POPAnimationExtras)
+
+- (void)pop_applyDragCoefficient
+{
+  CGFloat k = POPAnimationDragCoefficient();
+  if (k != 0 && k != 1)
+    self.speed = 1 / k;
+}
+
+@end
+
+@implementation POPSpringAnimation (POPAnimationExtras)
+
+static const CGFloat POPBouncy3NormalizationRange = 20.0;
+static const CGFloat POPBouncy3NormalizationScale = 1.7;
+static const CGFloat POPBouncy3BouncinessNormalizedMin = 0.0;
+static const CGFloat POPBouncy3BouncinessNormalizedMax = 0.8;
+static const CGFloat POPBouncy3SpeedNormalizedMin = 0.5;
+static const CGFloat POPBouncy3SpeedNormalizedMax = 200;
+static const CGFloat POPBouncy3FrictionInterpolationMax = 0.01;
+
++ (void)convertBounciness:(CGFloat)bounciness speed:(CGFloat)speed toTension:(CGFloat *)outTension friction:(CGFloat *)outFriction mass:(CGFloat *)outMass
+{
+  double b = POPNormalize(bounciness / POPBouncy3NormalizationScale, 0, POPBouncy3NormalizationRange);
+  b = POPProjectNormal(b, POPBouncy3BouncinessNormalizedMin, POPBouncy3BouncinessNormalizedMax);
+
+  double s = POPNormalize(speed / POPBouncy3NormalizationScale, 0, POPBouncy3NormalizationRange);
+
+  CGFloat tension = POPProjectNormal(s, POPBouncy3SpeedNormalizedMin, POPBouncy3SpeedNormalizedMax);
+  CGFloat friction = POPQuadraticOutInterpolation(b, POPBouncy3NoBounce(tension), POPBouncy3FrictionInterpolationMax);
+
+  tension = POP_ANIMATION_TENSION_FOR_QC_TENSION(tension);
+  friction = POP_ANIMATION_FRICTION_FOR_QC_FRICTION(friction);
+
+  if (outTension) {
+    *outTension = tension;
+  }
+
+  if (outFriction) {
+    *outFriction = friction;
+  }
+
+  if (outMass) {
+    *outMass = 1.0;
+  }
+}
+
++ (void)convertTension:(CGFloat)tension friction:(CGFloat)friction toBounciness:(CGFloat *)outBounciness speed:(CGFloat *)outSpeed
+{
+  // Convert to QC values, in which our calculations are done.
+  CGFloat qcFriction = QC_FRICTION_FOR_POP_ANIMATION_FRICTION(friction);
+  CGFloat qcTension = QC_TENSION_FOR_POP_ANIMATION_TENSION(tension);
+
+  // Friction is a function of bounciness and tension, according to the following:
+  // friction = POPQuadraticOutInterpolation(b, POPBouncy3NoBounce(tension), POPBouncy3FrictionInterpolationMax);
+  // Solve for bounciness, given a tension and friction.
+
+  CGFloat nobounceTension = POPBouncy3NoBounce(qcTension);
+  CGFloat bounciness1, bounciness2;
+
+  POPQuadraticSolve((nobounceTension - POPBouncy3FrictionInterpolationMax),      // a
+                  2 * (POPBouncy3FrictionInterpolationMax - nobounceTension),  // b
+                  (nobounceTension - qcFriction),                             // c
+                  bounciness1,                                                // x1
+                  bounciness2);                                               // x2
+
+
+  // Choose the quadratic solution within the normalized bounciness range
+  CGFloat projectedNormalizedBounciness = (bounciness2 < POPBouncy3BouncinessNormalizedMax) ? bounciness2 : bounciness1;
+  CGFloat projectedNormalizedSpeed = qcTension;
+
+  // Reverse projection + normalization
+  CGFloat bounciness = ((POPBouncy3NormalizationRange * POPBouncy3NormalizationScale) / (POPBouncy3BouncinessNormalizedMax - POPBouncy3BouncinessNormalizedMin)) * (projectedNormalizedBounciness - POPBouncy3BouncinessNormalizedMin);
+  CGFloat speed = ((POPBouncy3NormalizationRange * POPBouncy3NormalizationScale) / (POPBouncy3SpeedNormalizedMax - POPBouncy3SpeedNormalizedMin)) * (projectedNormalizedSpeed - POPBouncy3SpeedNormalizedMin);
+
+  // Write back results
+  if (outBounciness) {
+    *outBounciness = bounciness;
+  }
+
+  if (outSpeed) {
+    *outSpeed = speed;
+  }
+}
+
+@end