bounds.js

用来在地图上做操作GIS,在地图上做标记

        return this.contains(ll.lon, ll.lat, inclusive);
    },

    /**
     * APIMethod: containsPixel
     * 
     * Parameters:
     * px - {<OpenLayers.Pixel>}
     * inclusive - {Boolean} Whether or not to include the border. Default is
     *     true.
     *
     * Returns:
     * {Boolean} The passed-in pixel is within this bounds.
     */
    containsPixel:function(px, inclusive) {
        return this.contains(px.x, px.y, inclusive);
    },
    
    /**
     * APIMethod: contains
     * 
     * Parameters:
     * x - {Float}
     * y - {Float}
     * inclusive - {Boolean} Whether or not to include the border. Default is
     *     true.
     *
     * Returns:
     * {Boolean} Whether or not the passed-in coordinates are within this
     *     bounds.
     */
    contains:function(x, y, inclusive) {
    
        //set default
        if (inclusive == null) {
            inclusive = true;
        }
        
        var contains = false;
        if (inclusive) {
            contains = ((x >= this.left) && (x <= this.right) && 
                        (y >= this.bottom) && (y <= this.top));
        } else {
            contains = ((x > this.left) && (x < this.right) && 
                        (y > this.bottom) && (y < this.top));
        }              
        return contains;
    },

    /**
     * APIMethod: intersectsBounds
     * 
     * Parameters:
     * bounds - {<OpenLayers.Bounds>}
     * inclusive - {<Boolean>} Whether or not to include the border.  Default
     *     is true.
     *
     * Returns:
     * {Boolean} The passed-in OpenLayers.Bounds object intersects this bounds.
     *     Simple math just check if either contains the other, allowing for
     *     partial.
     */
    intersectsBounds:function(bounds, inclusive) {

        if (inclusive == null) {
            inclusive = true;
        }
        var inBottom = (bounds.bottom == this.bottom && bounds.top == this.top) ?
                    true : (((bounds.bottom > this.bottom) && (bounds.bottom < this.top)) || 
                           ((this.bottom > bounds.bottom) && (this.bottom < bounds.top))); 
        var inTop = (bounds.bottom == this.bottom && bounds.top == this.top) ?
                    true : (((bounds.top > this.bottom) && (bounds.top < this.top)) ||
                           ((this.top > bounds.bottom) && (this.top < bounds.top))); 
        var inRight = (bounds.right == this.right && bounds.left == this.left) ?
                    true : (((bounds.right > this.left) && (bounds.right < this.right)) ||
                           ((this.right > bounds.left) && (this.right < bounds.right))); 
        var inLeft = (bounds.right == this.right && bounds.left == this.left) ?
                    true : (((bounds.left > this.left) && (bounds.left < this.right)) || 
                           ((this.left > bounds.left) && (this.left < bounds.right))); 

        return (this.containsBounds(bounds, true, inclusive) ||
                bounds.containsBounds(this, true, inclusive) ||
                ((inTop || inBottom ) && (inLeft || inRight )));
    },
    
    /**
     * APIMethod: containsBounds
     * 
     * bounds - {<OpenLayers.Bounds>}
     * partial - {<Boolean>} If true, only part of passed-in bounds needs be
     *     within this bounds.  If false, the entire passed-in bounds must be
     *     within. Default is false
     * inclusive - {<Boolean>} Whether or not to include the border. Default is
     *     true.
     *
     * Returns:
     * {Boolean} The passed-in bounds object is contained within this bounds. 
     */
    containsBounds:function(bounds, partial, inclusive) {

        //set defaults
        if (partial == null) {
            partial = false;
        }
        if (inclusive == null) {
            inclusive = true;
        }

        var inLeft;
        var inTop;
        var inRight;
        var inBottom;
        
        if (inclusive) {
            inLeft = (bounds.left >= this.left) && (bounds.left <= this.right);
            inTop = (bounds.top >= this.bottom) && (bounds.top <= this.top);
            inRight= (bounds.right >= this.left) && (bounds.right <= this.right);
            inBottom = (bounds.bottom >= this.bottom) && (bounds.bottom <= this.top);
        } else {
            inLeft = (bounds.left > this.left) && (bounds.left < this.right);
            inTop = (bounds.top > this.bottom) && (bounds.top < this.top);
            inRight= (bounds.right > this.left) && (bounds.right < this.right);
            inBottom = (bounds.bottom > this.bottom) && (bounds.bottom < this.top);
        }
        
        return (partial) ? (inTop || inBottom ) && (inLeft || inRight ) 
                         : (inTop && inLeft && inBottom && inRight);
    },

    /** 
     * APIMethod: determineQuadrant
     * 
     * Parameters:
     * lonlat - {<OpenLayers.LonLat>}
     * 
     * Returns:
     * {String} The quadrant ("br" "tr" "tl" "bl") of the bounds in which the
     *     coordinate lies.
     */
    determineQuadrant: function(lonlat) {
    
        var quadrant = "";
        var center = this.getCenterLonLat();
        
        quadrant += (lonlat.lat < center.lat) ? "b" : "t";
        quadrant += (lonlat.lon < center.lon) ? "l" : "r";
    
        return quadrant; 
    },

    /**
     * APIMethod: wrapDateLine
     *  
     * Parameters:
     * maxExtent - {<OpenLayers.Bounds>}
     * options - {Object} Some possible options are:
     *                    leftTolerance - {float} Allow for a margin of error 
     *                                            with the 'left' value of this 
     *                                            bound.
     *                                            Default is 0.
     *                    rightTolerance - {float} Allow for a margin of error 
     *                                             with the 'right' value of 
     *                                             this bound.
     *                                             Default is 0.
     * 
     * Returns:
     * {<OpenLayers.Bounds>} A copy of this bounds, but wrapped around the 
     *                       "dateline" (as specified by the borders of 
     *                       maxExtent). Note that this function only returns 
     *                       a different bounds value if this bounds is 
     *                       *entirely* outside of the maxExtent. If this 
     *                       bounds straddles the dateline (is part in/part 
     *                       out of maxExtent), the returned bounds will be 
     *                       merely a copy of this one.
     */
    wrapDateLine: function(maxExtent, options) {    
        options = options || {};
        
        var leftTolerance = options.leftTolerance || 0;
        var rightTolerance = options.rightTolerance || 0;

        var newBounds = this.clone();
    
        if (maxExtent) {

           //shift right?
           while ( newBounds.left < maxExtent.left && 
                   (newBounds.right - rightTolerance) <= maxExtent.left ) { 
                newBounds = newBounds.add(maxExtent.getWidth(), 0);
           }

           //shift left?
           while ( (newBounds.left + leftTolerance) >= maxExtent.right && 
                   newBounds.right > maxExtent.right ) { 
                newBounds = newBounds.add(-maxExtent.getWidth(), 0);
           }
        }
                
        return newBounds;
    },

    CLASS_NAME: "OpenLayers.Bounds"
});

/** 
 * APIFunction: fromString
 * Alternative constructor that builds a new OpenLayers.Bounds from a 
 *     parameter string
 * 
 * Parameters: 
 * str - {String}Comma-separated bounds string. (ex. <i>"5,42,10,45"</i>)
 * 
 * Returns:
 * {<OpenLayers.Bounds>} New bounds object built from the 
 *                       passed-in String.
 */
OpenLayers.Bounds.fromString = function(str) {
    var bounds = str.split(",");
    return OpenLayers.Bounds.fromArray(bounds);
};

/** 
 * APIFunction: fromArray
 * Alternative constructor that builds a new OpenLayers.Bounds
 *     from an array
 * 
 * Parameters:
 * bbox - {Array(Float)} Array of bounds values (ex. <i>[5,42,10,45]</i>)
 *
 * Returns:
 * {<OpenLayers.Bounds>} New bounds object built from the passed-in Array.
 */
OpenLayers.Bounds.fromArray = function(bbox) {
    return new OpenLayers.Bounds(parseFloat(bbox[0]),
                                 parseFloat(bbox[1]),
                                 parseFloat(bbox[2]),
                                 parseFloat(bbox[3]));
};

/** 
 * APIFunction: fromSize
 * Alternative constructor that builds a new OpenLayers.Bounds
 *     from a size
 * 
 * Parameters:
 * size - {<OpenLayers.Size>} 
 *
 * Returns:
 * {<OpenLayers.Bounds>} New bounds object built from the passed-in size.
 */
OpenLayers.Bounds.fromSize = function(size) {
    return new OpenLayers.Bounds(0,
                                 size.h,
                                 size.w,
                                 0);
};

/**
 * Function: oppositeQuadrant
 * Get the opposite quadrant for a given quadrant string.
 *
 * Parameters:
 * quadrant - {String} two character quadrant shortstring
 *
 * Returns:
 * {String} The opposing quadrant ("br" "tr" "tl" "bl"). For Example, if 
 *          you pass in "bl" it returns "tr", if you pass in "br" it 
 *          returns "tl", etc.
 */
OpenLayers.Bounds.oppositeQuadrant = function(quadrant) {
    var opp = "";
    
    opp += (quadrant.charAt(0) == 't') ? 'b' : 't';
    opp += (quadrant.charAt(1) == 'l') ? 'r' : 'l';
    
    return opp;
};