SOURCE CODE: Uize.Widget.Bar
VIEW REFERENCE

/*______________
|       ______  |   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 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: 5
  codeCompleteness: 100
  testCompleteness: 0
  docCompleteness: 25
*/

/*?
  Introduction
    The =Uize.Widget.Bar= class implements a widget for displaying numerical values using a bar, with full and empty indicators and an optional value knob.

    *DEVELOPERS:* `Chris van Rensburg`, `Bryan Hsueh`

    This module supports both horizontally and vertically oriented bars.
*/

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

    /*** Class Constructor ***/
      var
        _class = _superclass.subclass (),
        _classPrototype = _class.prototype
      ;

    /*** Private Instance Methods ***/
      _classPrototype._conformValue = function (_value) {
        var
          _this = this,
          _minValue = _this._minValidValue == _undefined ? _this._minValue : _this._minValidValue,
          _increments = _this._increments
        ;
        return (
          Uize.constrain (
            _increments ? (_minValue + Math.round ((_value - _minValue) / _increments) * _increments) : _value,
            _minValue,
            _this._maxValidValue == _undefined ? _this._maxValue : _this._maxValidValue
          )
        );
      };

      _classPrototype._updateUi = function () {
        var _this = this;
        if (_this.isWired) {
          var
            _orientationNo = _this._orientationNo,
            _trackDimsObj = _Uize_Node.getDimensions (_this._trackNode),
            _trackDims = [_trackDimsObj.width,_trackDimsObj.height],
            _knobNode = _this._knobNode,
            _knobDimsObj = _Uize_Node.getDimensions (_knobNode),
            _knobDims = [_knobDimsObj.width,_knobDimsObj.height],
            _scaleFunc = _this._scaleFunc,
            _scaleMin = _scaleFunc(_this._minValue),
            _scaleMax = _scaleFunc(_this._maxValue),
            _scaleVal = _scaleFunc(_this._value),
            _knobVirtualPos = Math.round ((_scaleVal - _scaleMin) / (_scaleMax - _scaleMin) * (_trackDims [_orientationNo] - _knobDims [_orientationNo])),
            _knobPos = _orientationNo ? _trackDims [1] - _knobDims [1] - _knobVirtualPos : _knobVirtualPos,
            _knobCenter = Math.round (_knobPos + _knobDims [_orientationNo] / 2),
            _value = Uize.isNumber (_this._decimalPlacesToDisplay)
              ? _this._value.toFixed (_this._decimalPlacesToDisplay)
              : _this._value
          ;
          if (_knobNode) {
            _knobNode.style [_orientationNo ? 'top' : 'left'] = _knobPos + 'px';
            _knobNode.title = _value;
          }
          _this._fullNode &&
            _Uize_Node.setClipRect (
              _this._fullNode,
              _orientationNo ? _knobCenter : 0,
              _orientationNo ? _trackDims [0] : _knobCenter,
              _trackDims [1],
              0
            )
          ;
          _this._emptyNode &&
            _Uize_Node.setClipRect (
              _this._emptyNode,
              0,
              _trackDims [0],
              _orientationNo ? _knobCenter : _trackDims [1],
              _orientationNo ? 0 : _knobCenter
            )
          ;
          _this._valueNode &&
            _Uize_Node.setInnerHtml (
              _this._valueNode,
              Uize.isNumber (_this._decimalPlacesToDisplay)
                ? _this._value.toFixed (_this._decimalPlacesToDisplay)
                : _this._value
            )
          ;
        }
      };

    /*** Public Instance Methods ***/
      _classPrototype.updateUi = _classPrototype._updateUi;

      _classPrototype.wireUi = function () {
        var _this = this;
        if (!_this.isWired) {
          _this._orientationNo = _this._orientation == 'vertical' ? 1 : 0;
          _this._trackNode = _this.getNode ('track');
            /*?
              Implied Nodes
                track
                  The =track= implied node acts as a "guide" in which a bar's knob is to move. This node should be transparent when using the optional =full= and =empty= implied nodes, in order for those nodes to be visible to the user. When not using those nodes, the track image can be set in the CSS style for this node or can be a child node.

                  NOTES
                  - this implied node is required
            */
          _this._knobNode = _this.getNode ('knob');
            /*?
              Implied Nodes
                knob
                  The =knob= implied node acts as an indicator for a bar's current value and - for sliders - is wired up for drag-and-drop and provides the user a way to change the value. This node must be a child node of the =track= implied node.

                  NOTES
                  - this implied node is required
            */
          _this._fullNode = _this.getNode ('full');
            /*?
              Implied Nodes
                full
                  The optional =full= implied node acts as an indicator for the "full" side of a bar. For vertical bars, the full side is on the bottom side of the knob. For horizontal bars, the full side is on the left side of the knob.

                  To display correctly, this node should occupy the same space in the layout as the optional =empty= implied node and must have the same dimension on the axis of the knob's motion (ie. height for vertical bars, and width for horizontal bars) as the =track= implied node. It's not necessary that this node occupy the same space in the layout as the =track= implied node - the full/empty indicators could be off to the side, outside of the bar's track. However, in many cases you'll see bars with the full/empty indicators right over the track.

                  NOTES
                  - this implied node is optional
                  - compare to the =empty= implied node
            */
          _this._emptyNode = _this.getNode ('empty');
            /*?
              Implied Nodes
                empty
                  The optional =empty= implied node acts as an indicator for the "empty" side of a bar. For vertical bars, the empty side is on the top side of the knob. For horizontal bars, the empty side is on the right side of the knob.

                  To display correctly, this node should occupy the same space in the layout as the optional =full= implied node and must have the same dimension on the axis of the knob's motion (ie. height for vertical bars, and width for horizontal bars) as the =track= implied node. It's not necessary that this node occupy the same space in the layout as the =track= implied node - the full/empty indicators could be off to the side, outside of the bar's track. However, in many cases you'll see bars with the full/empty indicators right over the track.

                  NOTES
                  - this implied node is optional
                  - compare to the =full= implied node
            */
          _this._valueNode = _this.getNode ('value');
            /*?
              Implied Nodes
                value
                  The optional =value= implied node provides a convenient way to display a bar's current value. When this node is present, its innerHTML will be set to the bar's value, every time it changes.

                  NOTES
                  - this implied node is optional
            */

          _superclass.prototype.wireUi.call (_this);
        }
      };

    /*** Public Static Properties ***/
      _class.presets = {};
        /*?
          Static Properties
            Uize.Widget.Bar.presets
              [DOCUMENT]
        */

    /*** Register Properties ***/
      function _conformValueAndUpdateUi () {
        var _this = this;
        _this.set ({_value:_this._conformValue (_this._value)});
        _this._updateUi ();
      }

      _class.registerProperties ({
        _decimalPlacesToDisplay:'decimalPlacesToDisplay',
          /*?
            State Properties
              decimalPlacesToDisplay
                [DOCUMENT]
          */
        _increments:{
          name:'increments',
          onChange:_conformValueAndUpdateUi,
          value:1
          /*?
            State Properties
              increments
                [DOCUMENT]
          */
        },
        // if set, this is the min valid value, otherwise, use minValue
        _minValidValue:{
          name:'minValidValue',
          onChange:_conformValueAndUpdateUi
          /*?
            State Properties
              minValidValue
                [DOCUMENT]
          */
        },
        _minValue:{
          name:'minValue',
          onChange:_conformValueAndUpdateUi,
          value:0
          /*?
            State Properties
              minValue
                [DOCUMENT]
          */
        },
        // if set, this is the max valid value, otherwise, use maxValue
        _maxValidValue:{
          name:'maxValidValue',
          onChange:_conformValueAndUpdateUi
          /*?
            State Properties
              maxValidValue
                [DOCUMENT]
          */
        },
        _maxValue:{
          name:'maxValue',
          onChange:_conformValueAndUpdateUi,
          value:100
          /*?
            State Properties
              maxValue
                [DOCUMENT]
          */
        },
        _orientation:{
          name:'orientation',
          value:'vertical'
          /*?
            State Properties
              orientation
                [DOCUMENT]
          */
        },
        // this function can show the value in differe scale: eg, log(x+1), 1-1/x, x^2, etc.
        _scaleFunc:{
          name:'scaleFunc',
          value:function (_x) {return _x;}
          /*?
            State Properties
              scaleFunc
                [DOCUMENT]
          */
        },
        _value:{
          name:'value',
          conformer:_classPrototype._conformValue,
          onChange:_classPrototype._updateUi,
          value:0
          /*?
            State Properties
              value
                [DOCUMENT]
          */
        }
      });

    return _class;
  }
});