A nice iOS extension that gives CAKeyframeAnimation support for all of the complex easing curves found at http://easings.net
Add pod 'CalmParametricAnimations' to your Podfile or download the source here
CalmParametricAnimations supports the following curves (type ParametricTimeBlock):
typedef double (^ParametricTimeBlock)(double time)
sineIn
sineOut
sineInOut
squashedSineInOut
linear
appleIn
appleOut
appleInOut
backIn
backOut
backInOut
easeInBackOut
easeOutDramatic
quadraticIn
quadraticOut
cubicIn
cubicOut
cubicInOut
circularIn
circularOut
expoIn
expoOut
expoInOut
elasticIn
elasticOut
variableElasticOut (intensity) -> ParametricTimeBlock
bezierEvaluator (time, point1, point2) -> ParametricTimeBlock
arc (radius, center) -> ParametricTimeBlock
These can the be evaluated directly as functions passing double time from 0 - 1, or by using one of the "value blocks" we’ve defined:
double
point
size
rect
color
transform3D
Each of these value blocks has a corresponding extension method on CAKeyframeAnimation that allows passing of the key-path, the time function. For example:
+ (instancetype)animationWithKeyPath:(NSString *)path
timeFxn:(ParametricTimeBlock)timeFxn
fromRect:(CGRect)fromValue
toRect:(CGRect)toValue;
which will producte an animation that interpolates between the two rects according to the easing curve, with the duration set after initialization.