FRP.Helm.Transition

Contains all data structures for describing transitions, composing and animating them.

Types

type Transition a = StateT a (Writer [(a, Time)])

A type describing a combosable transition. The writer keeps record of all the frames in the transition. The state holds the current value of the transition. This allows you to easily compose transitions using do notation.

data TransitionStatus

A variety of statuses that can be used to control a transition.

Constructors

Cycle

The transition will repeat forever.

Pause

The transition will be paused and won't changed until resumed.

Once

The transition is cycled once and then stops.

Set Time

The transition will reset to a certain point in time.

class Interpolate a where

Defines a value that can be interpolated. An example instance of this class follows:

 data YourDataType = YourDataConstructor SomeInterpolableType SomeOtherInterpolableType deriving Generic

 instance Interpolate YourDataType
   interpolate 0.5 (YourDataConstructor 3 5) (YourDataConstructor 5 7) == YourDataConstructor 4 6

Methods

interpolate :: Double -> a -> a -> a

Instances

Interpolate Bool

Interpolate Char

Interpolate Double

Interpolate Float

Interpolate Int

Interpolate Int8

Interpolate Int16

Interpolate Int32

Interpolate Int64

Interpolate Integer

Interpolate Word

Interpolate Word8

Interpolate Word16

Interpolate Word32

Interpolate Word64

Interpolate Color

Interpolate (Double, Double)

Creating

waypoint :: Interpolate a => a -> Time -> Transition a a

Adds a value to the transition monad that will be the next point in the transition.

startWith :: Interpolate a => a -> Transition a b -> InternalTransition a

Starts a transition with an initial value.

 color = transition (constant $ Time.fps 60) (constant Cycle) $ startWith white $ do
   waypoint green (2 * second)
   waypoint red (5 * second)
   waypoint black (1 * second)
   waypoint yellow (2 * second)

fromList :: Interpolate a => [(a, Time)] -> InternalTransition a

Converts a list of tuples describing a waypoint value and time into a transition. The first element in the list is the starting value and time of the transition.

 color = transition (constant $ Time.fps 60) (constant Cycle) $ fromList [(white, 0), (green, 2 * second), (red, 5 * second), (black, 1 * second), (yellow, 2 * second)] 

Transitions

transition :: Interpolate a => SignalGen (Signal Time) -> SignalGen (Signal TransitionStatus) -> InternalTransition a -> SignalGen (Signal a)

Turns the internal representation of a transition into a signal. The provided time signal acts as the inner clock of the transition. The status signal can be used to control the transition, deciding whether the transition should cycle, go to a specific time, pause, stop or run once.

length :: InternalTransition a -> Double

How long it takes for the provided transition to end.