SOURCE CODE: Uize.Widget.Bar.Slider.Plus

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/*______________
|       ______  |   U I Z E    J A V A S C R I P T    F R A M E W O R K
|     /      /  |   ---------------------------------------------------
|    /    O /   |    MODULE : Uize.Widget.Bar.Slider.Plus Class
|   /    / /    |
|  /    / /  /| |    ONLINE : http://www.uize.com
| /____/ /__/_| | COPYRIGHT : (c)2005-2012 UIZE
|          /___ |   LICENSE : Available under MIT License or GNU General Public License
|_______________|             http://www.uize.com/license.html
*/

/* Module Meta Data
  type: Class
  importance: 1
  codeCompleteness: 100
  testCompleteness: 0
  docCompleteness: 10
*/

/*?
  Introduction
    The =Uize.Widget.Bar.Slider.Plus= class extends the barebones slider base class by adding buttons for incrementing and decrementing the slider's value.

    *DEVELOPERS:* `Chris van Rensburg`
*/

Uize.module ({
  name:'Uize.Widget.Bar.Slider.Plus',
  required:'Uize.Widget.Button',
  builder:function (_superclass) {
    /*** Variables for Scruncher Optimization ***/
      var
        _true = true,
        _false = false
      ;

    /*** Class Constructor ***/
      var
        _class = _superclass.subclass (
          null,
          function () {
            var _this = this;

            /*** add the buttons for adjusting the slider's value ***/
              function _stepButtonHandler (_event) {
                function _roundOffJsMathError (_value) {
                  return Math.round (_value * Math.pow (10,14)) / Math.pow (10,14); /* NOTE: this is a workaround for a REALLY ridiculous math inaccuracy in JavaScript when certain numbers are involved in multiplications. For example, .07 * 100 gives you 7.000000000000001 !!! */
                }
                var
                  _domEvent = _event.domEvent,
                  _divisions = _domEvent.shiftKey ? _this._stepsCoarse : (_domEvent.ctrlKey ? _this._stepsFine : _this._stepsNormal),
                  _minValue = _this.get ('minValue'),
                  _divisionSize = (_this.get ('maxValue') - _minValue) / _divisions,
                  _direction = _event.source.get ('name') == 'stepToMin' ? -1 : 1
                ;
                _this.set ({value:(Math [_direction < 0 ? 'ceil' : 'floor'] (_roundOffJsMathError ((_this - _minValue) / _divisionSize)) + _direction) * _divisionSize + _minValue});
              }
              _this._addChildButton ('setToMin',function () {_this.set ({value:_this.get ('minValue')})});
              _this._addChildButton ('setToMax',function () {_this.set ({value:_this.get ('maxValue')})});
              _this._addChildButton ('stepToMin',_stepButtonHandler);
              _this._addChildButton ('stepToMax',_stepButtonHandler);

              _this.wire ('Changed.value',function () {_this._updateButtonsState ()});
              _this._updateButtonsState ();
          }
        ),
        _classPrototype = _class.prototype
      ;

    /*** Private Instance Methods ***/
      _classPrototype._addChildButton = Uize.Widget.Button.addChildButton;

      _classPrototype._updateButtonsState = function () {
        var
          _this = this,
          _children = _this.children,
          _value = +_this,
          _toMinEnabled = _value != _this.get ('minValue') ? 'inherit' : false,
          _toMaxEnabled = _value != _this.get ('maxValue') ? 'inherit' : false
        ;
        _children.setToMin.set ({enabled:_toMinEnabled});
        _children.setToMax.set ({enabled:_toMaxEnabled});
        _children.stepToMin.set ({enabled:_toMinEnabled});
        _children.stepToMax.set ({enabled:_toMaxEnabled});
      };

    /*** Register Properties ***/
      _class.registerProperties ({
        _stepsCoarse:{
          name:'stepsCoarse',
          value:2
        },
        _stepsFine:{
          name:'stepsFine',
          value:25
        },
        _stepsNormal:{
          name:'stepsNormal',
          value:5
        }
      });

    return _class;
  }
});