/*
* DragZoomControl Class v1.1 
*  Copyright (c) 2005-2007, Andre Lewis, andre@earthcode.com
*
* Back Button functionality
*  Copyright (c)  2007, Richard Garland, papabear.newyork@gmail.com
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
* 
*       http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
* This class lets you add a control to the map which will let the user
*  zoom by dragging a rectangle.
*  More info on original GZoom at http://earthcode.com
*
* Back Button functionality provides the user with a one click means to return the map state 
*  to its state prior to the DragZoom.  Sequential DragZooms are backed out in reverse order.
*/

/**
* Constructor for DragZoomControl, which takes 3 option hashes and
*  uses them to customize the control.
* @param {opts_boxStyle} Named optional arguments:
*   opts_boxStyle.opacity {Number} Opacity from 0-1
*   opts_boxStyle.fillColor {String} Hex value of fill color
*   opts_boxStyle.border {String} CSS-style declaration of border
* @param {opts_other} Named optional arguments:
*   opts_other.buttonHTML {String} The zoom button HTML in non-activated state
*   opts_other.buttonStartingStyle {Object} A hash of css styles for the 
*     zoom button which are common to both un-activated and activated state
*   opts_other.buttonStyle {Object} A hash of css styles for the zoom button 
*     which will be applied when the button is in un-activated state.
*   opts_other.buttonZoomingHTML {String} HTML which is placed in the 
*     zoom button when the button is activated. 
*   opts_other.buttonZoomingStyle {Object} A hash of css styles for the 
*    zoom button which will be applied when the button is activated.
*   opts_other.overlayRemoveTime {Number} The number of milliseconds to wait before
*     removing the rectangle indicating the zoomed-in area after the zoom has happened.
*   opts_other.stickyZoomEnabled {Boolean} Whether or not the control stays in 
*     "zoom mode" until turned off. When true, the user can zoom repeatedly, 
*     until clicking on the zoom button again to turn zoom mode off.
*   opts_other.backButtonEnabled {Boolean} enables Back Button functionality
*   opts_other.backButtonHTML {String} The back button HTML
*   opts_other.backButtonStyle {Object} A hash of css styles for the back button
*     which will be applied when the button is created.	
* @param {opts_callbacks} Named optional arguments:
*   opts_callbacks.buttonclick {Function} Called when the DragZoom is activated 
*     by clicking on the "zoom" button. 
*   opts_callbacks.dragstart {Function} Called when user starts to drag a rectangle.
*     Callback args are x,y -- the PIXEL values, relative to the upper-left-hand 
*     corner of the map, where the user began dragging.
*   opts_callbacks.dragging {Function} Called repeatedly while the user is dragging.
*     Callback args are startX,startY, currentX,currentY -- the PIXEL values of the 
*     start of the drag, and the current drag point, respectively.
*   opts_callbacks.dragend {Function} Called when the user releases the mouse button 
*     after dragging the rectangle. Callback args are: NW {GLatLng}, NE {GLatLng}, 
*     SE {GLatLng}, SW {GLatLng}, NW {GPoint}, NE {GPoint}, SE {GPoint}, SW {GPoint}.
*     The first 4 are the latitudes/longitudes; the last 4 are the pixel coords on the map.
*   opts_callbacks.backbuttonclick {Function} Called when the back button is activated 
*     after the map context is restored. Callback args: methodCall (boolean) set true if
*     this backbuttonclick was to restore context set by the mathod call, else false.
* Method
*    this.saveMapContext(text) Call to push map context onto the backStack and set the button text 
*/
function DragZoomControl(opts_boxStyle, opts_other, opts_callbacks) {
    // Holds all information needed globally
    // Not all globals are initialized here
    this.globals = {
        draggingOn: false,
        cornerTopDiv: null,
        cornerRightDiv: null,
        cornerBottomDiv: null,
        cornerLeftDiv: null,
        mapPosition: null,
        outlineDiv: null,
        mapWidth: 0,
        mapHeight: 0,
        mapRatio: 0,
        startX: 0,
        startY: 0,
        borderCorrection: 0
    };

    //box style options
    this.globals.style = {
        opacity: .2,
        fillColor: "#000",
        border: "2px solid blue"
    };

    var style = this.globals.style;
    for (var s in opts_boxStyle) {
        style[s] = opts_boxStyle[s];
    }

    var borderStyleArray = style.border.split(' ');
    style.outlineWidth = parseInt(borderStyleArray[0].replace(/\D/g, ''));
    style.outlineColor = borderStyleArray[2];
    style.alphaIE = 'alpha(opacity=' + (style.opacity * 100) + ')';

    // map context stack for back button
    this.globals.backStack = [];

    // Other options
    this.globals.options = {
        buttonHTML: 'zoom ...',
        buttonStartingStyle:
      { width: '52px', border: '1px solid black', padding: '2px' },
        buttonStyle: { background: '#FFF' },
        backButtonHTML: 'zoom back',
        backButtonStyle: { background: '#FFF', display: 'none' },
        buttonZoomingHTML: 'Drag a region on the map',
        buttonZoomingStyle: { background: '#FF0' },
        overlayRemoveTime: 6000,
        backButtonEnabled: false,
        stickyZoomEnabled: false
    };

    for (var s in opts_other) {
        this.globals.options[s] = opts_other[s]
    }

    // callbacks: buttonclick, dragstart, dragging, dragend, backbuttonclick 
    if (opts_callbacks == null) {
        opts_callbacks = {}
    }
    this.globals.callbacks = opts_callbacks;

}

DragZoomControl.prototype = new GControl();


/**
* Back Button functionality:	
* Method of this object called to save the map context before the zoom.
* @param {text} text string for the back button
*/
DragZoomControl.prototype.saveMapContext = function(text) {
    if (this.globals.options.backButtonEnabled) {
        this.saveBackContext_(text, true);
        this.globals.backButtonDiv.style.display = 'block';
    }
};


/**
* Creates a new button to control gzoom and appends to the button container div.
* @param {DOM Node} buttonContainerDiv created in main .initialize code
*/
DragZoomControl.prototype.initButton_ = function(buttonContainerDiv) {
    var G = this.globals;
    var buttonDiv = document.createElement('div');
    buttonDiv.innerHTML = G.options.buttonHTML;
    buttonDiv.id = 'gzoom-control';
    DragZoomUtil.style([buttonDiv], { cursor: 'pointer', zIndex: 200 });
    DragZoomUtil.style([buttonDiv], G.options.buttonStartingStyle);
    DragZoomUtil.style([buttonDiv], G.options.buttonStyle);
    buttonContainerDiv.appendChild(buttonDiv);
    return buttonDiv;
};

/**												
* Creates a second new button to control backup zoom and appends to the button container div.
* @param {DOM Node} buttonContainerDiv created in main .initialize code
*/
DragZoomControl.prototype.initBackButton_ = function(buttonContainerDiv) {	//**BB** entire function
    var G = this.globals;
    var backButtonDiv = document.createElement('div');
    backButtonDiv.innerHTML = G.options.backButtonHTML;
    backButtonDiv.id = 'gzoom-back';
    DragZoomUtil.style([backButtonDiv], { cursor: 'pointer', zIndex: 200 });
    DragZoomUtil.style([backButtonDiv], G.options.buttonStartingStyle);
    DragZoomUtil.style([backButtonDiv], G.options.backButtonStyle);
    buttonContainerDiv.appendChild(backButtonDiv);
    return backButtonDiv;
};

/**
* Sets button mode to zooming or otherwise, changes CSS & HTML.
* @param {String} mode Either "zooming" or not.
*/
DragZoomControl.prototype.setButtonMode_ = function(mode) {
    var G = this.globals;
    if (mode == 'zooming') {
        G.buttonDiv.innerHTML = G.options.buttonZoomingHTML;
        DragZoomUtil.style([G.buttonDiv], G.options.buttonStartingStyle);
        DragZoomUtil.style([G.buttonDiv], G.options.buttonZoomingStyle);
    } else {
        G.buttonDiv.innerHTML = G.options.buttonHTML;
        DragZoomUtil.style([G.buttonDiv], G.options.buttonStartingStyle);
        DragZoomUtil.style([G.buttonDiv], G.options.buttonStyle);
    }
};

/**
* Is called by GMap2's addOverlay method. Creates the zoom control
* divs and appends to the map div.
* @param {GMap2} map The map that has had this DragZoomControl added to it.
* @return {DOM Object} Div that holds the gzoomcontrol button
*/
DragZoomControl.prototype.initialize = function(map) {
    var G = this.globals;
    var me = this;
    var mapDiv = map.getContainer();

    // Create div for both buttons	
    var buttonContainerDiv = document.createElement("div");
    DragZoomUtil.style([buttonContainerDiv], { cursor: 'pointer', zIndex: 150 });

    // create and init the zoom button
    //DOM:button
    var buttonDiv = this.initButton_(buttonContainerDiv);

    // create and init the back button				
    //DOM:button
    var backButtonDiv = this.initBackButton_(buttonContainerDiv);

    // Add the two buttons to the map 					
    mapDiv.appendChild(buttonContainerDiv);

    //DOM:map covers
    var zoomDiv = document.createElement("div");
    zoomDiv.id = 'gzoom-map-cover';
    zoomDiv.innerHTML = '<div id="gzoom-outline" style="position:absolute;display:none;"></div><div id="gzoom-cornerTopDiv" style="position:absolute;display:none;"></div><div id="gzoom-cornerLeftDiv" style="position:absolute;display:none;"></div><div id="gzoom-cornerRightDiv" style="position:absolute;display:none;"></div><div id="gzoom-cornerBottomDiv" style="position:absolute;display:none;"></div>';
    DragZoomUtil.style([zoomDiv], { position: 'absolute', display: 'none', overflow: 'hidden', cursor: 'crosshair', zIndex: 101 });
    mapDiv.appendChild(zoomDiv);

    // add event listeners
    GEvent.addDomListener(buttonDiv, 'click', function(e) {
        me.buttonclick_(e);
    });
    GEvent.addDomListener(backButtonDiv, 'click', function(e) {
        me.backButtonclick_(e);
    });
    GEvent.addDomListener(zoomDiv, 'mousedown', function(e) {
        me.coverMousedown_(e);
    });
    GEvent.addDomListener(document, 'mousemove', function(e) {
        me.drag_(e);
    });
    GEvent.addDomListener(document, 'mouseup', function(e) {
        me.mouseup_(e);
    });

    // get globals
    G.mapPosition = DragZoomUtil.getElementPosition(mapDiv);
    G.outlineDiv = DragZoomUtil.gE("gzoom-outline");
    G.buttonDiv = DragZoomUtil.gE("gzoom-control");
    G.backButtonDiv = DragZoomUtil.gE("gzoom-back");
    G.mapCover = DragZoomUtil.gE("gzoom-map-cover");
    G.cornerTopDiv = DragZoomUtil.gE("gzoom-cornerTopDiv");
    G.cornerRightDiv = DragZoomUtil.gE("gzoom-cornerRightDiv");
    G.cornerBottomDiv = DragZoomUtil.gE("gzoom-cornerBottomDiv");
    G.cornerLeftDiv = DragZoomUtil.gE("gzoom-cornerLeftDiv");
    G.map = map;

    G.borderCorrection = G.style.outlineWidth * 2;
    this.setDimensions_();

    //styles
    this.initStyles_();
    return buttonContainerDiv;
};

/**
* Required by GMaps API for controls. 
* @return {GControlPosition} Default location for control
*/
DragZoomControl.prototype.getDefaultPosition = function() {
    return new GControlPosition(G_ANCHOR_TOP_LEFT, new GSize(3, 120));
};

/**
* Function called when mousedown event is captured.
* @param {Object} e 
*/
DragZoomControl.prototype.coverMousedown_ = function(e) {
    var G = this.globals;
    var pos = this.getRelPos_(e);
    G.startX = pos.left;
    G.startY = pos.top;

    DragZoomUtil.style([G.mapCover], { background: 'transparent', opacity: 1, filter: 'alpha(opacity=100)' });
    DragZoomUtil.style([G.outlineDiv], { left: G.startX + 'px', top: G.startY + 'px', display: 'block', width: '1px', height: '1px' });
    G.draggingOn = true;

    G.cornerTopDiv.style.top = (G.startY - G.mapHeight) + 'px';
    G.cornerTopDiv.style.display = 'block';
    G.cornerLeftDiv.style.left = (G.startX - G.mapWidth) + 'px';
    G.cornerLeftDiv.style.top = G.startY + 'px';
    G.cornerLeftDiv.style.display = 'block';

    G.cornerRightDiv.style.left = G.startX + 'px';
    G.cornerRightDiv.style.top = G.startY + 'px';
    G.cornerRightDiv.style.display = 'block';
    G.cornerBottomDiv.style.left = G.startX + 'px';
    G.cornerBottomDiv.style.top = G.startY + 'px';
    G.cornerBottomDiv.style.width = '0px';
    G.cornerBottomDiv.style.display = 'block';

    // invoke the callback if provided
    if (G.callbacks.dragstart != null) {
        G.callbacks.dragstart(G.startX, G.startY);
    }

    return false;
};

/**z
* Function called when drag event is captured
* @param {Object} e 
*/
DragZoomControl.prototype.drag_ = function(e) {
    var G = this.globals;

    document.onselectstart = function() {
        return false;
    };

    if (G.draggingOn) {
        var pos = this.getRelPos_(e);
        rect = this.getRectangle_(G.startX, G.startY, pos, G.mapRatio);

        if (rect.left) {
            addX = -rect.width;
        } else {
            addX = 0;
        }

        if (rect.top) {
            addY = -rect.height;
        } else {
            addY = 0;
        }

        DragZoomUtil.style([G.outlineDiv], { left: G.startX + addX + 'px', top: G.startY + addY + 'px', display: 'block', width: '1px', height: '1px' });

        G.outlineDiv.style.width = rect.width + "px";
        G.outlineDiv.style.height = rect.height + "px";

        G.cornerTopDiv.style.height = ((G.startY + addY) - (G.startY - G.mapHeight)) + 'px';
        G.cornerLeftDiv.style.top = (G.startY + addY) + 'px';
        G.cornerLeftDiv.style.width = ((G.startX + addX) - (G.startX - G.mapWidth)) + 'px';
        G.cornerRightDiv.style.top = G.cornerLeftDiv.style.top;
        G.cornerRightDiv.style.left = (G.startX + addX + rect.width + G.borderCorrection) + 'px';
        G.cornerBottomDiv.style.top = (G.startY + addY + rect.height + G.borderCorrection) + 'px';
        G.cornerBottomDiv.style.left = (G.startX - G.mapWidth + ((G.startX + addX) - (G.startX - G.mapWidth))) + 'px';
        G.cornerBottomDiv.style.width = (rect.width + G.borderCorrection) + 'px';

        // invoke callback if provided
        if (G.callbacks.dragging != null) {
            G.callbacks.dragging(G.startX, G.startY, rect.endX, rect.endY)
        }

        return false;
    }
};

/** 
* Function called when mouseup event is captured
* @param {Event} e
*/
DragZoomControl.prototype.mouseup_ = function(e) {
    var G = this.globals;
    if (G.draggingOn) {
        var pos = this.getRelPos_(e);
        G.draggingOn = false;

        var rect = this.getRectangle_(G.startX, G.startY, pos, G.mapRatio);

        if (rect.left) rect.endX = rect.startX - rect.width;
        if (rect.top) rect.endY = rect.startY - rect.height;

        this.resetDragZoom_();

        var nwpx = new GPoint(rect.startX, rect.startY);
        var nepx = new GPoint(rect.endX, rect.startY);
        var sepx = new GPoint(rect.endX, rect.endY);
        var swpx = new GPoint(rect.startX, rect.endY);
        var nw = G.map.fromContainerPixelToLatLng(nwpx);
        var ne = G.map.fromContainerPixelToLatLng(nepx);
        var se = G.map.fromContainerPixelToLatLng(sepx);
        var sw = G.map.fromContainerPixelToLatLng(swpx);

        var zoomAreaPoly = new GPolyline([nw, ne, se, sw, nw], G.style.outlineColor, G.style.outlineWidth + 1, .4);

        try {
            G.map.addOverlay(zoomAreaPoly);
            setTimeout(function() { G.map.removeOverlay(zoomAreaPoly) }, G.options.overlayRemoveTime);
        } catch (e) { }

        polyBounds = zoomAreaPoly.getBounds();
        var ne = polyBounds.getNorthEast();
        var sw = polyBounds.getSouthWest();
        var se = new GLatLng(sw.lat(), ne.lng());
        var nw = new GLatLng(ne.lat(), sw.lng());
        zoomLevel = G.map.getBoundsZoomLevel(polyBounds);
        center = polyBounds.getCenter();
        G.map.setCenter(center, zoomLevel);

        // invoke callback if provided
        if (G.callbacks.dragend != null) {
            G.callbacks.dragend(nw, ne, se, sw, nwpx, nepx, sepx, swpx);
        }

        //re-init if sticky
        if (G.options.stickyZoomEnabled) {
            //GLog.write("stickyZoomEnabled, re-initting");
            this.initCover_();
            if (G.options.backButtonEnabled) this.saveBackContext_(G.options.backButtonHTML, false); // save the map context for back button
            G.backButtonDiv.style.display = 'none';
        }
    }
};

/**
* Set the cover sizes according to the size of the map
*/
DragZoomControl.prototype.setDimensions_ = function() {
    var G = this.globals;
    var mapSize = G.map.getSize();
    G.mapWidth = mapSize.width;
    G.mapHeight = mapSize.height;
    G.mapRatio = G.mapHeight / G.mapWidth;
    DragZoomUtil.style([G.mapCover, G.cornerTopDiv, G.cornerRightDiv, G.cornerBottomDiv, G.cornerLeftDiv],
    { width: G.mapWidth + 'px', height: G.mapHeight + 'px' });
};

/**
* Initializes styles based on global parameters
*/
DragZoomControl.prototype.initStyles_ = function() {
    var G = this.globals;
    DragZoomUtil.style([G.mapCover, G.cornerTopDiv, G.cornerRightDiv, G.cornerBottomDiv, G.cornerLeftDiv],
    { filter: G.style.alphaIE, opacity: G.style.opacity, background: G.style.fillColor });
    G.outlineDiv.style.border = G.style.border;
};

/**
* Function called when the zoom button's click event is captured.
*/
DragZoomControl.prototype.buttonclick_ = function() {
    var G = this.globals;
    G.backButtonDiv.style.display = 'none';
    if (G.mapCover.style.display == 'block') { // reset if clicked before dragging 
        this.resetDragZoom_();
        if (G.options.backButtonEnabled) {
            this.restoreBackContext_();  // pop the backStack on a button reset
            if (G.backStack.length == 0) G.backButtonDiv.style.display = 'none';
        }
    } else {
        this.initCover_();
        if (G.options.backButtonEnabled) this.saveBackContext_(G.options.backButtonHTML, false); // save the map context for back button
    }
};

/**
* Back Button functionality:	
* Function called when the back button's click event is captured.
* calls the function to set the map context back to where it was before the zoom.
*/
DragZoomControl.prototype.backButtonclick_ = function() {
    var G = this.globals;
    if (G.options.backButtonEnabled) {
        this.restoreBackContext_();
        // invoke the callback if provided
        if (G.callbacks['backbuttonclick'] != null) {
            G.callbacks.backbuttonclick(G.methodCall);
        }
    }
};

/** 
* Back Button functionality:	
* Saves the map context and pushes it on the backStack for later use by the back button
*/
DragZoomControl.prototype.saveBackContext_ = function(text, methodCall) {
    var G = this.globals;
    var backFrame = {};
    backFrame["center"] = G.map.getCenter();
    backFrame["zoom"] = G.map.getZoom();
    backFrame["maptype"] = G.map.getCurrentMapType();
    backFrame["text"] = G.backButtonDiv.innerHTML; // this saves the previous button text
    backFrame["methodCall"] = methodCall; //This determines if it was an internal or method call
    G.backStack.push(backFrame);
    G.backButtonDiv.innerHTML = text;
    // Back Button is turned on in resetDragZoom_()
};

/** 
* Back Button functionality:	
* Pops the previous map context off of the backStack and restores the map to that context
*/
DragZoomControl.prototype.restoreBackContext_ = function() {
    var G = this.globals;
    var backFrame = G.backStack.pop();
    G.map.setCenter(backFrame["center"], backFrame["zoom"], backFrame["maptype"]);
    G.backButtonDiv.innerHTML = backFrame["text"];
    G.methodCall = backFrame["methodCall"];
    if (G.backStack.length == 0) G.backButtonDiv.style.display = 'none'; // if we're at the top of the stack, hide the back botton
};

/**
* Shows the cover over the map
*/
DragZoomControl.prototype.initCover_ = function() {
    var G = this.globals;
    G.mapPosition = DragZoomUtil.getElementPosition(G.map.getContainer());
    this.setDimensions_();
    this.setButtonMode_('zooming');
    DragZoomUtil.style([G.mapCover], { display: 'block', background: G.style.fillColor });
    DragZoomUtil.style([G.outlineDiv], { width: '0px', height: '0px' });

    //invoke callback if provided
    if (G.callbacks['buttonclick'] != null) {
        G.callbacks.buttonclick();
    }

};

/**
* Gets position of the mouse relative to the map
* @param {Object} e
*/
DragZoomControl.prototype.getRelPos_ = function(e) {
    var pos = DragZoomUtil.getMousePosition(e);
    var G = this.globals;
    return { top: (pos.top - G.mapPosition.top),
        left: (pos.left - G.mapPosition.left)
    };
};

/**
* Figures out the rectangle the user's trying to draw
* @param {Number} startX 
* @param {Number} startY
* @param {Object} pos
* @param {Number} ratio
* @return {Object} Describes the rectangle
*/
DragZoomControl.prototype.getRectangle_ = function(startX, startY, pos, ratio) {
    var left = false;
    var top = false;
    var dX = pos.left - startX;
    var dY = pos.top - startY;
    if (dX < 0) {
        dX = dX * -1;
        left = true;
    }
    if (dY < 0) {
        dY = dY * -1;
        top = true;
    }
    delta = dX > dY ? dX : dY;

    return {
        startX: startX,
        startY: startY,
        endX: startX + delta,
        endY: startY + parseInt(delta * ratio),
        width: delta,
        height: parseInt(delta * ratio),
        left: left,
        top: top
    }
};

/** 
* Resets CSS and button display when drag zoom done
*/
DragZoomControl.prototype.resetDragZoom_ = function() {
    var G = this.globals;
    DragZoomUtil.style([G.mapCover, G.cornerTopDiv, G.cornerRightDiv, G.cornerBottomDiv, G.cornerLeftDiv],
    { display: 'none', opacity: G.style.opacity, filter: G.style.alphaIE });
    G.outlineDiv.style.display = 'none';
    this.setButtonMode_('normal');
    if (G.options.backButtonEnabled && (G.backStack.length > 0)) G.backButtonDiv.style.display = 'block'; // show the back button
};



/* utility functions in DragZoomUtil.namespace */
var DragZoomUtil = {};

/**
* Alias function for getting element by id
* @param {String} sId
* @return {Object} DOM object with sId id
*/
DragZoomUtil.gE = function(sId) {
    return document.getElementById(sId);
}

/**
* A general-purpose function to get the absolute position
* of the mouse.
* @param {Object} e  Mouse event
* @return {Object} Describes position
*/
DragZoomUtil.getMousePosition = function(e) {
    var posX = 0;
    var posY = 0;
    if (!e) var e = window.event;
    if (e.pageX || e.pageY) {
        posX = e.pageX;
        posY = e.pageY;
    } else if (e.clientX || e.clientY) {
        posX = e.clientX +
      (document.documentElement.scrollLeft ? document.documentElement.scrollLeft : document.body.scrollLeft);
        posY = e.clientY +
      (document.documentElement.scrollTop ? document.documentElement.scrollTop : document.body.scrollTop);
    }
    return { left: posX, top: posY };
};

/**
* Gets position of element
* @param {Object} element
* @return {Object} Describes position
*/
DragZoomUtil.getElementPosition = function(element) {
    var leftPos = element.offsetLeft;          // initialize var to store calculations
    var topPos = element.offsetTop;            // initialize var to store calculations
    var parElement = element.offsetParent;     // identify first offset parent element  
    while (parElement != null) {                // move up through element hierarchy
        leftPos += parElement.offsetLeft;      // appending left offset of each parent
        topPos += parElement.offsetTop;
        parElement = parElement.offsetParent;  // until no more offset parents exist
    }
    return { left: leftPos, top: topPos };
};

/**
* Applies styles to DOM objects 
* @param {String/Object} elements Either comma-delimited list of ids 
*   or an array of DOM objects
* @param {Object} styles Hash of styles to be applied
*/
DragZoomUtil.style = function(elements, styles) {
    if (typeof (elements) == 'string') {
        elements = DragZoomUtil.getManyElements(elements);
    }
    for (var i = 0; i < elements.length; i++) {
        for (var s in styles) {
            elements[i].style[s] = styles[s];
        }
    }
};

/**
* Gets DOM elements array according to list of IDs
* @param {String} elementsString Comma-delimited list of IDs
* @return {Array} Array of DOM elements corresponding to s
*/
DragZoomUtil.getManyElements = function(idsString) {
    var idsArray = idsString.split(',');
    var elements = [];
    for (var i = 0; i < idsArray.length; i++) {
        elements[elements.length] = DragZoomUtil.gE(idsArray[i])
    };
    return elements;
};