Caterpillar

Relative scrolling animation in a fake collection view for iOS.

The animation class RelativeAnimation is a simple alternative to Facebook POP animations, good for animating rapid events and continuous gestures.

RelativeAnimation

Subclass of CAKeyframeAnimation. You may not set keyframe values or keyTimes. Instead you set the fromValue and toValue, with an optional timingBlock. This does not work with implicit animation, instead animations must be explicit. For implicit animation, there is the Seamless.framework. Allowed types are CATransform3D, NSPoint, CGPoint, NSSize, CGSize, and numbers which are treated as doubles. Opacity animation does not work properly. Rect animation must be broken up into components, for example position and bounds.size. Color animation is not supported.

@property (strong) id fromValue;

Required. The animation's apparent start value.

@property (strong) id toValue;

Required. The animation's apparent end value.

@property (copy) double (^timingBlock)(double);

A block that takes as an argument animation progress from 0 to 1, and returns animation progress that can extend below 0 and above 1.

@property (assign) BOOL absolute;

Animations run relative to the underlying model value. Behind the scenes, animations are additive, and the from and to values are converted to the old value minus the new value to zero. If absolute is YES, this conversion is not done.

@property (assign) NSUInteger steps;

The timingBlock is converted to keyframes. This determines how many are used. The default is 50.

+(double(^)(double))bezierWithControlPoints:(double)p1x :(double)p1y :(double)p2x :(double)p2y;

A convenience constructor that returns a block that can be used as the timingBlock.

+(double(^)(double))perfectBezier;

Equivalent to [RelativeAnimation bezierWithControlPoints:0.5 :0.0 :0.5 :1.0]; This is gives nice blending for interrupted animations.