# Yahoo! UI Library

### Slider Widget 2.8.2r1

Yahoo! UI Library > slider > Slider.js (source view)
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    /**
     * The Slider component is a UI control that enables the user to adjust
     * values in a finite range along one or two axes. Typically, the Slider
     * control is used in a web application as a rich, visual replacement
     * for an input box that takes a number as input. The Slider control can
     * also easily accommodate a second dimension, providing x,y output for
     * a selection point chosen from a rectangular region.
     *
     * @module    slider
     * @title     Slider Widget
     * @namespace YAHOO.widget
     * @requires  yahoo,dom,dragdrop,event
     * @optional  animation
     */
     (function () {

    var getXY = YAHOO.util.Dom.getXY,
        Event = YAHOO.util.Event,
        _AS   = Array.prototype.slice;

    /**
     * A DragDrop implementation that can be used as a background for a
     * slider.  It takes a reference to the thumb instance
     * so it can delegate some of the events to it.  The goal is to make the
     * thumb jump to the location on the background when the background is
     * clicked.
     *
     * @class Slider
     * @extends YAHOO.util.DragDrop
     * @uses YAHOO.util.EventProvider
     * @constructor
     * @param {String}      id     The id of the element linked to this instance
     * @param {String}      sGroup The group of related DragDrop items
     * @param {SliderThumb} oThumb The thumb for this slider
     * @param {String}      sType  The type of slider (horiz, vert, region)
     */
    function Slider(sElementId, sGroup, oThumb, sType) {

        Slider.ANIM_AVAIL = (!YAHOO.lang.isUndefined(YAHOO.util.Anim));

        if (sElementId) {
            this.init(sElementId, sGroup, true);
            this.initSlider(sType);
            this.initThumb(oThumb);
        }
    }

    YAHOO.lang.augmentObject(Slider,{
        /**
         * Factory method for creating a horizontal slider
         * @method YAHOO.widget.Slider.getHorizSlider
         * @static
         * @param {String} sBGElId the id of the slider's background element
         * @param {String} sHandleElId the id of the thumb element
         * @param {int} iLeft the number of pixels the element can move left
         * @param {int} iRight the number of pixels the element can move right
         * @param {int} iTickSize optional parameter for specifying that the element
         * should move a certain number pixels at a time.
         * @return {Slider} a horizontal slider control
         */
        getHorizSlider :
            function (sBGElId, sHandleElId, iLeft, iRight, iTickSize) {
                return new Slider(sBGElId, sBGElId,
                    new YAHOO.widget.SliderThumb(sHandleElId, sBGElId,
                                       iLeft, iRight, 0, 0, iTickSize), "horiz");
        },

        /**
         * Factory method for creating a vertical slider
         * @method YAHOO.widget.Slider.getVertSlider
         * @static
         * @param {String} sBGElId the id of the slider's background element
         * @param {String} sHandleElId the id of the thumb element
         * @param {int} iUp the number of pixels the element can move up
         * @param {int} iDown the number of pixels the element can move down
         * @param {int} iTickSize optional parameter for specifying that the element
         * should move a certain number pixels at a time.
         * @return {Slider} a vertical slider control
         */
        getVertSlider :
            function (sBGElId, sHandleElId, iUp, iDown, iTickSize) {
                return new Slider(sBGElId, sBGElId,
                    new YAHOO.widget.SliderThumb(sHandleElId, sBGElId, 0, 0,
                                       iUp, iDown, iTickSize), "vert");
        },

        /**
         * Factory method for creating a slider region like the one in the color
         * picker example
         * @method YAHOO.widget.Slider.getSliderRegion
         * @static
         * @param {String} sBGElId the id of the slider's background element
         * @param {String} sHandleElId the id of the thumb element
         * @param {int} iLeft the number of pixels the element can move left
         * @param {int} iRight the number of pixels the element can move right
         * @param {int} iUp the number of pixels the element can move up
         * @param {int} iDown the number of pixels the element can move down
         * @param {int} iTickSize optional parameter for specifying that the element
         * should move a certain number pixels at a time.
         * @return {Slider} a slider region control
         */
        getSliderRegion :
            function (sBGElId, sHandleElId, iLeft, iRight, iUp, iDown, iTickSize) {
                return new Slider(sBGElId, sBGElId,
                    new YAHOO.widget.SliderThumb(sHandleElId, sBGElId, iLeft, iRight,
                                       iUp, iDown, iTickSize), "region");
        },

        /**
         * Constant for valueChangeSource, indicating that the user clicked or
         * dragged the slider to change the value.
         * @property Slider.SOURCE_UI_EVENT
         * @final
         * @static
         * @default 1
         */
        SOURCE_UI_EVENT : 1,

        /**
         * Constant for valueChangeSource, indicating that the value was altered
         * by a programmatic call to setValue/setRegionValue.
         * @property Slider.SOURCE_SET_VALUE
         * @final
         * @static
         * @default 2
         */
        SOURCE_SET_VALUE : 2,

        /**
         * Constant for valueChangeSource, indicating that the value was altered
         * by hitting any of the supported keyboard characters.
         * @property Slider.SOURCE_KEY_EVENT
         * @final
         * @static
         * @default 2
         */
        SOURCE_KEY_EVENT : 3,

        /**
         * By default, animation is available if the animation utility is detected.
         * @property Slider.ANIM_AVAIL
         * @static
         * @type boolean
         */
        ANIM_AVAIL : false
    },true);

    YAHOO.extend(Slider, YAHOO.util.DragDrop, {

        /**
         * Tracks the state of the mouse button to aid in when events are fired.
         *
         * @property _mouseDown
         * @type boolean
         * @default false
         * @private
         */
        _mouseDown : false,

        /**
         * Override the default setting of dragOnly to true.
         * @property dragOnly
         * @type boolean
         * @default true
         */
        dragOnly : true,

        /**
         * Initializes the slider.  Executed in the constructor
         * @method initSlider
         * @param {string} sType the type of slider (horiz, vert, region)
         */
        initSlider: function(sType) {

            /**
             * The type of the slider (horiz, vert, region)
             * @property type
             * @type string
             */
            this.type = sType;

            //this.removeInvalidHandleType("A");

            this.logger = new YAHOO.widget.LogWriter(this.toString());

            /**
             * Event the fires when the value of the control changes.  If
             * the control is animated the event will fire every point
             * along the way.
             * @event change
             * @param {int} newOffset|x the new offset for normal sliders, or the new
             *                          x offset for region sliders
             * @param {int} y the number of pixels the thumb has moved on the y axis
             *                (region sliders only)
             */
            this.createEvent("change", this);

            /**
             * Event that fires at the beginning of a slider thumb move.
             * @event slideStart
             */
            this.createEvent("slideStart", this);

            /**
             * Event that fires at the end of a slider thumb move
             * @event slideEnd
             */
            this.createEvent("slideEnd", this);

            /**
             * Overrides the isTarget property in YAHOO.util.DragDrop
             * @property isTarget
             * @private
             */
            this.isTarget = false;

            /**
             * Flag that determines if the thumb will animate when moved
             * @property animate
             * @type boolean
             */
            this.animate = Slider.ANIM_AVAIL;

            /**
             * Set to false to disable a background click thumb move
             * @property backgroundEnabled
             * @type boolean
             */
            this.backgroundEnabled = true;

            /**
             * Adjustment factor for tick animation, the more ticks, the
             * faster the animation (by default)
             * @property tickPause
             * @type int
             */
            this.tickPause = 40;

            /**
             * Enables the arrow, home and end keys, defaults to true.
             * @property enableKeys
             * @type boolean
             */
            this.enableKeys = true;

            /**
             * Specifies the number of pixels the arrow keys will move the slider.
             * Default is 20.
             * @property keyIncrement
             * @type int
             */
            this.keyIncrement = 20;

            /**
             * moveComplete is set to true when the slider has moved to its final
             * destination.  For animated slider, this value can be checked in
             * the onChange handler to make it possible to execute logic only
             * when the move is complete rather than at all points along the way.
             * Deprecated because this flag is only useful when the background is
             * clicked and the slider is animated.  If the user drags the thumb,
             * the flag is updated when the drag is over ... the final onDrag event
             * fires before the mouseup the ends the drag, so the implementer will
             * never see it.
             *
             * @property moveComplete
             * @type Boolean
             * @deprecated use the slideEnd event instead
             */
            this.moveComplete = true;

            /**
             * If animation is configured, specifies the length of the animation
             * in seconds.
             * @property animationDuration
             * @type int
             * @default 0.2
             */
            this.animationDuration = 0.2;

            /**
             * Constant for valueChangeSource, indicating that the user clicked or
             * dragged the slider to change the value.
             * @property SOURCE_UI_EVENT
             * @final
             * @default 1
             * @deprecated use static Slider.SOURCE_UI_EVENT
             */
            this.SOURCE_UI_EVENT = 1;

            /**
             * Constant for valueChangeSource, indicating that the value was altered
             * by a programmatic call to setValue/setRegionValue.
             * @property SOURCE_SET_VALUE
             * @final
             * @default 2
             * @deprecated use static Slider.SOURCE_SET_VALUE
             */
            this.SOURCE_SET_VALUE = 2;

            /**
             * When the slider value changes, this property is set to identify where
             * the update came from.  This will be either 1, meaning the slider was
             * clicked or dragged, or 2, meaning that it was set via a setValue() call.
             * This can be used within event handlers to apply some of the logic only
             * when dealing with one source or another.
             * @property valueChangeSource
             * @type int
             * @since 2.3.0
             */
            this.valueChangeSource = 0;

            /**
             * Indicates whether or not events will be supressed for the current
             * slide operation
             * @property _silent
             * @type boolean
             * @private
             */
            this._silent = false;

            /**
             * Saved offset used to protect against NaN problems when slider is
             * set to display:none
             * @property lastOffset
             * @type [int, int]
             */
            this.lastOffset = [0,0];
        },

        /**
         * Initializes the slider's thumb. Executed in the constructor.
         * @method initThumb
         * @param {YAHOO.widget.SliderThumb} t the slider thumb
         */
        initThumb: function(t) {

            var self = this;

            /**
             * A YAHOO.widget.SliderThumb instance that we will use to
             * reposition the thumb when the background is clicked
             * @property thumb
             * @type YAHOO.widget.SliderThumb
             */
            this.thumb = t;

            t.cacheBetweenDrags = true;

            if (t._isHoriz && t.xTicks && t.xTicks.length) {
                this.tickPause = Math.round(360 / t.xTicks.length);
            } else if (t.yTicks && t.yTicks.length) {
                this.tickPause = Math.round(360 / t.yTicks.length);
            }

            this.logger.log("tickPause: " + this.tickPause);

            // delegate thumb methods
            t.onAvailable = function() {
                    return self.setStartSliderState();
                };
            t.onMouseDown = function () {
                    self._mouseDown = true;
                    self.logger.log('thumb mousedown');
                    return self.focus();
                };
            t.startDrag = function() {
                    self.logger.log('thumb startDrag');
                    self._slideStart();
                };
            t.onDrag = function() {
                    self.logger.log('thumb drag');
                    self.fireEvents(true);
                };
            t.onMouseUp = function() {
                    self.thumbMouseUp();
                };

        },

        /**
         * Executed when the slider element is available
         * @method onAvailable
         */
        onAvailable: function() {
            this._bindKeyEvents();
        },

        /**
         * Sets up the listeners for keydown and key press events.
         *
         * @method _bindKeyEvents
         * @protected
         */
        _bindKeyEvents : function () {
            Event.on(this.id, "keydown",  this.handleKeyDown,  this, true);
            Event.on(this.id, "keypress", this.handleKeyPress, this, true);
        },

        /**
         * Executed when a keypress event happens with the control focused.
         * Prevents the default behavior for navigation keys.  The actual
         * logic for moving the slider thumb in response to a key event
         * happens in handleKeyDown.
         * @param {Event} e the keypress event
         */
        handleKeyPress: function(e) {
            if (this.enableKeys) {
                var kc = Event.getCharCode(e);

                switch (kc) {
                    case 0x25: // left
                    case 0x26: // up
                    case 0x27: // right
                    case 0x28: // down
                    case 0x24: // home
                    case 0x23: // end
                        Event.preventDefault(e);
                        break;
                    default:
                }
            }
        },

        /**
         * Executed when a keydown event happens with the control focused.
         * Updates the slider value and display when the keypress is an
         * arrow key, home, or end as long as enableKeys is set to true.
         * @param {Event} e the keydown event
         */
        handleKeyDown: function(e) {
            if (this.enableKeys) {
                var kc = Event.getCharCode(e),
                    t  = this.thumb,
                    h  = this.getXValue(),
                    v  = this.getYValue(),
                    changeValue = true;

                switch (kc) {

                    // left
                    case 0x25: h -= this.keyIncrement; break;

                    // up
                    case 0x26: v -= this.keyIncrement; break;

                    // right
                    case 0x27: h += this.keyIncrement; break;

                    // down
                    case 0x28: v += this.keyIncrement; break;

                    // home
                    case 0x24: h = t.leftConstraint;
                               v = t.topConstraint;
                               break;

                    // end
                    case 0x23: h = t.rightConstraint;
                               v = t.bottomConstraint;
                               break;

                    default:   changeValue = false;
                }

                if (changeValue) {
                    if (t._isRegion) {
                        this._setRegionValue(Slider.SOURCE_KEY_EVENT, h, v, true);
                    } else {
                        this._setValue(Slider.SOURCE_KEY_EVENT,
                            (t._isHoriz ? h : v), true);
                    }
                    Event.stopEvent(e);
                }

            }
        },

        /**
         * Initialization that sets up the value offsets once the elements are ready
         * @method setStartSliderState
         */
        setStartSliderState: function() {

            this.logger.log("Fixing state");

            this.setThumbCenterPoint();

            /**
             * The basline position of the background element, used
             * to determine if the background has moved since the last
             * operation.
             * @property baselinePos
             * @type [int, int]
             */
            this.baselinePos = getXY(this.getEl());

            this.thumb.startOffset = this.thumb.getOffsetFromParent(this.baselinePos);

            if (this.thumb._isRegion) {
                if (this.deferredSetRegionValue) {
                    this._setRegionValue.apply(this, this.deferredSetRegionValue);
                    this.deferredSetRegionValue = null;
                } else {
                    this.setRegionValue(0, 0, true, true, true);
                }
            } else {
                if (this.deferredSetValue) {
                    this._setValue.apply(this, this.deferredSetValue);
                    this.deferredSetValue = null;
                } else {
                    this.setValue(0, true, true, true);
                }
            }
        },

        /**
         * When the thumb is available, we cache the centerpoint of the element so
         * we can position the element correctly when the background is clicked
         * @method setThumbCenterPoint
         */
        setThumbCenterPoint: function() {

            var el = this.thumb.getEl();

            if (el) {
                /**
                 * The center of the slider element is stored so we can
                 * place it in the correct position when the background is clicked.
                 * @property thumbCenterPoint
                 * @type {"x": int, "y": int}
                 */
                this.thumbCenterPoint = {
                        x: parseInt(el.offsetWidth/2, 10),
                        y: parseInt(el.offsetHeight/2, 10)
                };
            }

        },

        /**
         * Locks the slider, overrides YAHOO.util.DragDrop
         * @method lock
         */
        lock: function() {
            this.logger.log("locking");
            this.thumb.lock();
            this.locked = true;
        },

        /**
         * Unlocks the slider, overrides YAHOO.util.DragDrop
         * @method unlock
         */
        unlock: function() {
            this.logger.log("unlocking");
            this.thumb.unlock();
            this.locked = false;
        },

        /**
         * Handles mouseup event on the thumb
         * @method thumbMouseUp
         * @private
         */
        thumbMouseUp: function() {
            this._mouseDown = false;
            this.logger.log("thumb mouseup");
            if (!this.isLocked()) {
                this.endMove();
            }

        },

        onMouseUp: function() {
            this._mouseDown = false;
            this.logger.log("background mouseup");
            if (this.backgroundEnabled && !this.isLocked()) {
                this.endMove();
            }
        },

        /**
         * Returns a reference to this slider's thumb
         * @method getThumb
         * @return {SliderThumb} this slider's thumb
         */
        getThumb: function() {
            return this.thumb;
        },

        /**
         * Try to focus the element when clicked so we can add
         * accessibility features
         * @method focus
         * @private
         */
        focus: function() {
            this.logger.log("focus");
            this.valueChangeSource = Slider.SOURCE_UI_EVENT;

            // Focus the background element if possible
            var el = this.getEl();

            if (el.focus) {
                try {
                    el.focus();
                } catch(e) {
                    // Prevent permission denied unhandled exception in FF that can
                    // happen when setting focus while another element is handling
                    // the blur.  @TODO this is still writing to the error log
                    // (unhandled error) in FF1.5 with strict error checking on.
                }
            }

            this.verifyOffset();

            return !this.isLocked();
        },

        /**
         * Event that fires when the value of the slider has changed
         * @method onChange
         * @param {int} firstOffset the number of pixels the thumb has moved
         * from its start position. Normal horizontal and vertical sliders will only
         * have the firstOffset.  Regions will have both, the first is the horizontal
         * offset, the second the vertical.
         * @param {int} secondOffset the y offset for region sliders
         * @deprecated use instance.subscribe("change") instead
         */
        onChange: function (firstOffset, secondOffset) {
            /* override me */
            this.logger.log("onChange: " + firstOffset + ", " + secondOffset);
        },

        /**
         * Event that fires when the at the beginning of the slider thumb move
         * @method onSlideStart
         * @deprecated use instance.subscribe("slideStart") instead
         */
        onSlideStart: function () {
            /* override me */
            this.logger.log("onSlideStart");
        },

        /**
         * Event that fires at the end of a slider thumb move
         * @method onSliderEnd
         * @deprecated use instance.subscribe("slideEnd") instead
         */
        onSlideEnd: function () {
            /* override me */
            this.logger.log("onSlideEnd");
        },

        /**
         * Returns the slider's thumb offset from the start position
         * @method getValue
         * @return {int} the current value
         */
        getValue: function () {
            return this.thumb.getValue();
        },

        /**
         * Returns the slider's thumb X offset from the start position
         * @method getXValue
         * @return {int} the current horizontal offset
         */
        getXValue: function () {
            return this.thumb.getXValue();
        },

        /**
         * Returns the slider's thumb Y offset from the start position
         * @method getYValue
         * @return {int} the current vertical offset
         */
        getYValue: function () {
            return this.thumb.getYValue();
        },

        /**
         * Provides a way to set the value of the slider in code.
         *
         * @method setValue
         * @param {int} newOffset the number of pixels the thumb should be
         * positioned away from the initial start point
         * @param {boolean} skipAnim set to true to disable the animation
         * for this move action (but not others).
         * @param {boolean} force ignore the locked setting and set value anyway
         * @param {boolean} silent when true, do not fire events
         * @return {boolean} true if the move was performed, false if it failed
         */
        setValue: function() {
            var args = _AS.call(arguments);
            args.unshift(Slider.SOURCE_SET_VALUE);
            return this._setValue.apply(this,args);
        },

        /**
         * Worker function to execute the value set operation.  Accepts type of
         * set operation in addition to the usual setValue params.
         *
         * @method _setValue
         * @param source {int} what triggered the set (e.g. Slider.SOURCE_SET_VALUE)
         * @param {int} newOffset the number of pixels the thumb should be
         * positioned away from the initial start point
         * @param {boolean} skipAnim set to true to disable the animation
         * for this move action (but not others).
         * @param {boolean} force ignore the locked setting and set value anyway
         * @param {boolean} silent when true, do not fire events
         * @return {boolean} true if the move was performed, false if it failed
         * @protected
         */
        _setValue: function(source, newOffset, skipAnim, force, silent) {
            var t = this.thumb, newX, newY;

            if (!t.available) {
                this.logger.log("defer setValue until after onAvailble");
                this.deferredSetValue = arguments;
                return false;
            }

            if (this.isLocked() && !force) {
                this.logger.log("Can't set the value, the control is locked");
                return false;
            }

            if ( isNaN(newOffset) ) {
                this.logger.log("setValue, Illegal argument: " + newOffset);
                return false;
            }

            if (t._isRegion) {
                this.logger.log("Call to setValue for region Slider ignored. Use setRegionValue","warn");
                return false;
            }

            this.logger.log("setValue " + newOffset);

            this._silent = silent;
            this.valueChangeSource = source || Slider.SOURCE_SET_VALUE;

            t.lastOffset = [newOffset, newOffset];
            this.verifyOffset();

            this._slideStart();

            if (t._isHoriz) {
                newX = t.initPageX + newOffset + this.thumbCenterPoint.x;
                this.moveThumb(newX, t.initPageY, skipAnim);
            } else {
                newY = t.initPageY + newOffset + this.thumbCenterPoint.y;
                this.moveThumb(t.initPageX, newY, skipAnim);
            }

            return true;
        },

        /**
         * Provides a way to set the value of the region slider in code.
         * @method setRegionValue
         * @param {int} newOffset the number of pixels the thumb should be
         * positioned away from the initial start point (x axis for region)
         * @param {int} newOffset2 the number of pixels the thumb should be
         * positioned away from the initial start point (y axis for region)
         * @param {boolean} skipAnim set to true to disable the animation
         * for this move action (but not others).
         * @param {boolean} force ignore the locked setting and set value anyway
         * @param {boolean} silent when true, do not fire events
         * @return {boolean} true if the move was performed, false if it failed
         */
        setRegionValue : function () {
            var args = _AS.call(arguments);
            args.unshift(Slider.SOURCE_SET_VALUE);
            return this._setRegionValue.apply(this,args);
        },

        /**
         * Worker function to execute the value set operation.  Accepts type of
         * set operation in addition to the usual setValue params.
         *
         * @method _setRegionValue
         * @param source {int} what triggered the set (e.g. Slider.SOURCE_SET_VALUE)
         * @param {int} newOffset the number of pixels the thumb should be
         * positioned away from the initial start point (x axis for region)
         * @param {int} newOffset2 the number of pixels the thumb should be
         * positioned away from the initial start point (y axis for region)
         * @param {boolean} skipAnim set to true to disable the animation
         * for this move action (but not others).
         * @param {boolean} force ignore the locked setting and set value anyway
         * @param {boolean} silent when true, do not fire events
         * @return {boolean} true if the move was performed, false if it failed
         * @protected
         */
        _setRegionValue: function(source, newOffset, newOffset2, skipAnim, force, silent) {
            var t = this.thumb, newX, newY;

            if (!t.available) {
                this.logger.log("defer setRegionValue until after onAvailble");
                this.deferredSetRegionValue = arguments;
                return false;
            }

            if (this.isLocked() && !force) {
                this.logger.log("Can't set the value, the control is locked");
                return false;
            }

            if ( isNaN(newOffset) ) {
                this.logger.log("setRegionValue, Illegal argument: " + newOffset);
                return false;
            }

            if (!t._isRegion) {
                this.logger.log("Call to setRegionValue for non-region Slider ignored. Use setValue","warn");
                return false;
            }

            this._silent = silent;

            this.valueChangeSource = source || Slider.SOURCE_SET_VALUE;

            t.lastOffset = [newOffset, newOffset2];
            this.verifyOffset();

            this._slideStart();

            newX = t.initPageX + newOffset + this.thumbCenterPoint.x;
            newY = t.initPageY + newOffset2 + this.thumbCenterPoint.y;
            this.moveThumb(newX, newY, skipAnim);

            return true;
        },

        /**
         * Checks the background position element position.  If it has moved from the
         * baseline position, the constraints for the thumb are reset
         * @method verifyOffset
         * @return {boolean} True if the offset is the same as the baseline.
         */
        verifyOffset: function() {

            var xy = getXY(this.getEl()),
                t  = this.thumb;

            if (!this.thumbCenterPoint || !this.thumbCenterPoint.x) {
                this.setThumbCenterPoint();
            }

            if (xy) {

                this.logger.log("newPos: " + xy);

                if (xy[0] != this.baselinePos[0] || xy[1] != this.baselinePos[1]) {
                    this.logger.log("background moved, resetting constraints");

                    // Reset background
                    this.setInitPosition();
                    this.baselinePos = xy;

                    // Reset thumb
                    t.initPageX = this.initPageX + t.startOffset[0];
                    t.initPageY = this.initPageY + t.startOffset[1];
                    t.deltaSetXY = null;
                    this.resetThumbConstraints();

                    return false;
                }
            }

            return true;
        },

        /**
         * Move the associated slider moved to a timeout to try to get around the
         * mousedown stealing moz does when I move the slider element between the
         * cursor and the background during the mouseup event
         * @method moveThumb
         * @param {int} x the X coordinate of the click
         * @param {int} y the Y coordinate of the click
         * @param {boolean} skipAnim don't animate if the move happend onDrag
         * @param {boolean} midMove set to true if this is not terminating
         * the slider movement
         * @private
         */
        moveThumb: function(x, y, skipAnim, midMove) {

            var t = this.thumb,
                self = this,
                p,_p,anim;

            if (!t.available) {
                this.logger.log("thumb is not available yet, aborting move");
                return;
            }

            this.logger.log("move thumb, x: "  + x + ", y: " + y);

            t.setDelta(this.thumbCenterPoint.x, this.thumbCenterPoint.y);

            _p = t.getTargetCoord(x, y);
            p = [Math.round(_p.x), Math.round(_p.y)];

            if (this.animate && t._graduated && !skipAnim) {
                this.logger.log("graduated");
                this.lock();

                // cache the current thumb pos
                this.curCoord = getXY(this.thumb.getEl());
                this.curCoord = [Math.round(this.curCoord[0]), Math.round(this.curCoord[1])];

                setTimeout( function() { self.moveOneTick(p); }, this.tickPause );

            } else if (this.animate && Slider.ANIM_AVAIL && !skipAnim) {
                this.logger.log("animating to " + p);

                this.lock();

                anim = new YAHOO.util.Motion(
                        t.id, { points: { to: p } },
                        this.animationDuration,
                        YAHOO.util.Easing.easeOut );

                anim.onComplete.subscribe( function() {
                        self.logger.log("Animation completed _mouseDown:" + self._mouseDown);
                        self.unlock();
                        if (!self._mouseDown) {
                            self.endMove();
                        }
                    });
                anim.animate();

            } else {
                t.setDragElPos(x, y);
                if (!midMove && !this._mouseDown) {
                    this.endMove();
                }
            }
        },

        _slideStart: function() {
            if (!this._sliding) {
                if (!this._silent) {
                    this.onSlideStart();
                    this.fireEvent("slideStart");
                }
                this._sliding = true;
                this.moveComplete = false; // for backward compatibility. Deprecated
            }
        },

        _slideEnd: function() {
            if (this._sliding) {
                // Reset state before firing slideEnd
                var silent = this._silent;
                this._sliding = false;
                this.moveComplete = true; // for backward compatibility. Deprecated
                this._silent = false;
                if (!silent) {
                    this.onSlideEnd();
                    this.fireEvent("slideEnd");
                }
            }
        },

        /**
         * Move the slider one tick mark towards its final coordinate.  Used
         * for the animation when tick marks are defined
         * @method moveOneTick
         * @param {int[]} the destination coordinate
         * @private
         */
        moveOneTick: function(finalCoord) {

            var t = this.thumb,
                self = this,
                nextCoord = null,
                tmpX, tmpY;

            if (t._isRegion) {
                nextCoord = this._getNextX(this.curCoord, finalCoord);
                tmpX = (nextCoord !== null) ? nextCoord[0] : this.curCoord[0];
                nextCoord = this._getNextY(this.curCoord, finalCoord);
                tmpY = (nextCoord !== null) ? nextCoord[1] : this.curCoord[1];

                nextCoord = tmpX !== this.curCoord[0] || tmpY !== this.curCoord[1] ?
                    [ tmpX, tmpY ] : null;
            } else if (t._isHoriz) {
                nextCoord = this._getNextX(this.curCoord, finalCoord);
            } else {
                nextCoord = this._getNextY(this.curCoord, finalCoord);
            }

            this.logger.log("moveOneTick: " +
                    " finalCoord: " + finalCoord +
                    " this.curCoord: " + this.curCoord +
                    " nextCoord: " + nextCoord);

            if (nextCoord) {

                // cache the position
                this.curCoord = nextCoord;

                // move to the next coord
                this.thumb.alignElWithMouse(t.getEl(), nextCoord[0] + this.thumbCenterPoint.x, nextCoord[1] + this.thumbCenterPoint.y);

                // check if we are in the final position, if not make a recursive call
                if (!(nextCoord[0] == finalCoord[0] && nextCoord[1] == finalCoord[1])) {
                    setTimeout(function() { self.moveOneTick(finalCoord); },
                            this.tickPause);
                } else {
                    this.unlock();
                    if (!this._mouseDown) {
                        this.endMove();
                    }
                }
            } else {
                this.unlock();
                if (!this._mouseDown) {
                    this.endMove();
                }
            }
        },

        /**
         * Returns the next X tick value based on the current coord and the target coord.
         * @method _getNextX
         * @private
         */
        _getNextX: function(curCoord, finalCoord) {
            this.logger.log("getNextX: " + curCoord + ", " + finalCoord);
            var t = this.thumb,
                thresh,
                tmp = [],
                nextCoord = null;

            if (curCoord[0] > finalCoord[0]) {
                thresh = t.tickSize - this.thumbCenterPoint.x;
                tmp = t.getTargetCoord( curCoord[0] - thresh, curCoord[1] );
                nextCoord = [tmp.x, tmp.y];
            } else if (curCoord[0] < finalCoord[0]) {
                thresh = t.tickSize + this.thumbCenterPoint.x;
                tmp = t.getTargetCoord( curCoord[0] + thresh, curCoord[1] );
                nextCoord = [tmp.x, tmp.y];
            } else {
                // equal, do nothing
            }

            return nextCoord;
        },

        /**
         * Returns the next Y tick value based on the current coord and the target coord.
         * @method _getNextY
         * @private
         */
        _getNextY: function(curCoord, finalCoord) {
            var t = this.thumb,
                thresh,
                tmp = [],
                nextCoord = null;

            if (curCoord[1] > finalCoord[1]) {
                thresh = t.tickSize - this.thumbCenterPoint.y;
                tmp = t.getTargetCoord( curCoord[0], curCoord[1] - thresh );
                nextCoord = [tmp.x, tmp.y];
            } else if (curCoord[1] < finalCoord[1]) {
                thresh = t.tickSize + this.thumbCenterPoint.y;
                tmp = t.getTargetCoord( curCoord[0], curCoord[1] + thresh );
                nextCoord = [tmp.x, tmp.y];
            } else {
                // equal, do nothing
            }

            return nextCoord;
        },

        /**
         * Resets the constraints before moving the thumb.
         * @method b4MouseDown
         * @private
         */
        b4MouseDown: function(e) {
            if (!this.backgroundEnabled) {
                return false;
            }

            this.thumb.autoOffset();
            this.baselinePos = [];
        },

        /**
         * Handles the mousedown event for the slider background
         * @method onMouseDown
         * @private
         */
        onMouseDown: function(e) {
            if (!this.backgroundEnabled || this.isLocked()) {
                return false;
            }

            this._mouseDown = true;

            var x = Event.getPageX(e),
                y = Event.getPageY(e);

            this.logger.log("bg mousedown: " + x + "," + y);

            this.focus();
            this._slideStart();
            this.moveThumb(x, y);
        },

        /**
         * Handles the onDrag event for the slider background
         * @method onDrag
         * @private
         */
        onDrag: function(e) {
            this.logger.log("background drag");
            if (this.backgroundEnabled && !this.isLocked()) {
                var x = Event.getPageX(e),
                    y = Event.getPageY(e);
                this.moveThumb(x, y, true, true);
                this.fireEvents();
            }
        },

        /**
         * Fired when the slider movement ends
         * @method endMove
         * @private
         */
        endMove: function () {
            this.logger.log("endMove");
            this.unlock();
            this.fireEvents();
            this._slideEnd();
        },

        /**
         * Resets the X and Y contraints for the thumb.  Used in lieu of the thumb
         * instance's inherited resetConstraints because some logic was not
         * applicable.
         * @method resetThumbConstraints
         * @protected
         */
        resetThumbConstraints: function () {
            var t = this.thumb;

            t.setXConstraint(t.leftConstraint, t.rightConstraint, t.xTickSize);
            t.setYConstraint(t.topConstraint, t.bottomConstraint, t.xTickSize);
        },

        /**
         * Fires the change event if the value has been changed.  Ignored if we are in
         * the middle of an animation as the event will fire when the animation is
         * complete
         * @method fireEvents
         * @param {boolean} thumbEvent set to true if this event is fired from an event
         *                  that occurred on the thumb.  If it is, the state of the
         *                  thumb dd object should be correct.  Otherwise, the event
         *                  originated on the background, so the thumb state needs to
         *                  be refreshed before proceeding.
         * @private
         */
        fireEvents: function (thumbEvent) {

            var t = this.thumb, newX, newY, newVal;

            if (!thumbEvent) {
                t.cachePosition();
            }

            if (! this.isLocked()) {
                if (t._isRegion) {
                    newX = t.getXValue();
                    newY = t.getYValue();

                    if (newX != this.previousX || newY != this.previousY) {
                        if (!this._silent) {
                            this.onChange(newX, newY);
                            this.fireEvent("change", { x: newX, y: newY });
                        }
                    }

                    this.previousX = newX;
                    this.previousY = newY;

                } else {
                    newVal = t.getValue();
                    if (newVal != this.previousVal) {
                        this.logger.log("Firing onchange: " + newVal);
                        if (!this._silent) {
                            this.onChange( newVal );
                            this.fireEvent("change", newVal);
                        }
                    }
                    this.previousVal = newVal;
                }

            }
        },

        /**
         * Slider toString
         * @method toString
         * @return {string} string representation of the instance
         */
        toString: function () {
            return ("Slider (" + this.type +") " + this.id);
        }

    });

    YAHOO.lang.augmentProto(Slider, YAHOO.util.EventProvider);

    YAHOO.widget.Slider = Slider;
    })();

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