Toggle data types

Toggle a

the abstract type of a Toggle handle.

ToggleResources

currently a list of (attribute,value) pairs specifying the default configuration values you want to override when creating a Toggle:

type ToggleResource = [ToggleResource]

data ToggleResource
 =
    {- the feedback to give for the different stages of the interaction. -}
   ToggleFeedback TogFeedback
    {- initial picture to display for toggle -}
 | ToggleInitial  (Picture -> Size -> Int -> Picture)
    {- the labels to use. -}
 | ToggleLabelOn  Picture
 | ToggleLabelOff  Picture
    {-
      How to toggle the state upon completion of interaction,
      i.e., how to map toggle state to new one.
    -}
 | ToggleFunction (Bool -> Bool)
    {- the interaction function -}
 | ToggleIaction  Iaction

IState

The different interaction states used by the Toggle:

data IState 
 = IIdle
 | ICompleted
 | IFocus
 | IRunning
 | ISuspended
 | IAborted
   deriving Eq

TogFeedback

a record of feedback functions to use for a Toggle instance.

type TogFeedback =
 (  {- normal/completed feedback -}
  TogFbackFunction,
    {- focus feedback -}
  TogFbackFunction,
    {- running feedback -}
  TogFbackFunction,
    {- suspended feedback -}
  TogFbackFunction)

TogFbackFunction

a feedback function value, which given a style context (see TogFbackStyle) and a label, returns the picture to display for the Toggle.

type TogFbackFunction =
     {- style to use -}
    TogFbackStyle 
     {- toggle label -}
 -> Picture
     {- on \/ off -}
 -> Bool
 -> ResizeablePicture

TogFbackStyle

A record of attributes to use for drawing a Toggle:

data TogFbackStyle =
 TogFbackStyle
    {- anchor for the label -}
   CompassDirection
    {- foreground and bground (in idle states) -}
   Colour Colour
    {- active bg&fg -}
   Colour Colour
    {- pen to use when item is selected -}
   Pen
    {- lighter/darker fg&bg colours -}
   Pen Pen
    {- lighter/darker active fg&bg colours -}
   Pen Pen
    {- relief in idle mode -}
   Relief
    {- borderwidths -}
   Int Int

Iaction

the interaction state function, maps current interaction state and device events to new state:

type Iaction = DeviceEvent -> IState -> Maybe IState

based on a device event and the current interaction state, an Iaction function may return the following two values:
Returns:

Nothing

event was not of interest, it may be passed on. Interaction stays the same.

Just newIState

move to interaction state newIState and change the feedback of the Selector to reflect the change in state.

ToggleName

The ToggleName is used to identify a particular Toggle when merging them together with the combineToggles operator.

type ToggleName = String

combine t1 t2 =
 combineToggles [setToggleName "foo" t1,
                 setToggleName "bar" t2]

Using the ToggleNames, we can selectively disable/enable sub-toggles via the combined Toggle handle.

disable_toggle t1 t2 =
  combineToggles t1 t2            >>= \t ->
  activateToggle t ["bar"] False  >>
  ...

which disables the t2 toggle.