src/StdLibExt/RangeSlider.dcl

   1 definition module RangeSlider
   2
   3 import StdEnv, StdIO
   4
   5 /**     A (RangeSlider id dir width range action atts) value describes a control that allows users to select values from the
   6         given range. The parameters have the following meaning:
   7         id:             the identification value of the range slider;
   8         dir:    the direction of the range slider (Horizontal or Vertical);
   9         width:  the length of the range slider;
  10         range:  the range {values=[v_0, ..., v_n],index=i}; here i is the 0-based index of the currently selected value, v_i.
  11                         When the user selects another value, then index will have the corresponding value;
  12         action: the function that is applied to the current local and process state of the control whenever the user has used
  13                         the range slider;
  14         atts:   the standard set of control attributes.
  15
  16         Author: Peter Achten
  17         E-mail: P.Achten@cs.ru.nl
  18         Date:   january 2008
  19         Uses:   Clean 2.2, Object I/O
  20 */
  21 ::      RangeSliderId a
  22 ::      RangeSlider a ls pst
  23         =       RangeSlider (RangeSliderId a) Direction ControlWidth (Range a) (RangeAction a *(ls,pst)) [ControlAttribute *(ls,pst)]
  24 ::      Range a
  25         =       { values        :: ![a]
  26                 , index         :: !RangeIndex
  27                 }
  28 ::      RangeIndex
  29         :== Int
  30 ::      RangeAction a st
  31         :== a -> st -> st
  32
  33 openRangeSliderId :: !*env -> (!RangeSliderId a,!*env) | Ids env
  34
  35 instance Controls (RangeSlider a)
  36
  37 /** getRangeSliderIndex id pSt
  38                 yields (Just index) of the selected value of the indicated range slider if it exists, and Nothing otherwise.
  39         getRangeSliderValue id pSt
  40                 yields (Maybe (values!!index)) of the indicated range slider if it exists, and Nothing otherwise.
  41         setRangeSliderIndex id i pSt
  42                 sets the current index value of the indicated range slider to i, and applies the action function to that value
  43                 and the current local and process state.
  44                 If the indicated range slider does not exist, nothing happens.
  45         setRangeSliderValue id v pSt
  46                 updates the value at the current index of the indicated range slider to v, and applies the action function to
  47                 that value and the current local and process state.
  48                 If the indicated range slider does not exist, nothing happens.
  49 */
  50 getRangeSliderIndex :: !(RangeSliderId a)        !(PSt .ps) -> (!Maybe RangeIndex,!PSt .ps)
  51 getRangeSliderValue :: !(RangeSliderId a)        !(PSt .ps) -> (!Maybe a,         !PSt .ps)
  52 setRangeSliderIndex :: !(RangeSliderId a) !Index !(PSt .ps) ->                     PSt .ps
  53 setRangeSliderValue :: !(RangeSliderId a) !a     !(PSt .ps) ->                     PSt .ps