EncodedPolyline: Added encode() method

The write() method will follow in the next commit.
2012-12-28 01:31:24 +01:00
parent 8651e05e75
commit 510d42b12f
2 changed files with 83 additions and 0 deletions
@@ -130,5 +130,80 @@ OpenLayers.Format.EncodedPolyline = OpenLayers.Class(OpenLayers.Format, {
        return points;
    },
    /**
     * Method: encode
     * Serialize an array of n-dimensional points and return an encoded string
     *
     * Parameters:
     * points - {Array(Array(int))} An array containing n-dimensional
     *          arrays of coordinates
     * dims - {int} The dimension of the points that should be read
     *
     * Returns:
     * {String} An encoded string
     */
    encode: function (points, dims) {
        var encoded_points = "";
        var lastPoint = new Array(dims);
        for (var i = 0; i < lastPoint.length; ++i)
            lastPoint[i] = 0;
        for (var i = 0; i < points.length; i++) {
            var point = points[i];
            for (var dim = 0; dim < lastPoint.length; ++dim) {
                var delta = point[dim] - lastPoint[dim];
                encoded_points += this.encodeSignedNumber(delta);
            }
            lastPoint = point;
        }
        return encoded_points;
    },
    /**
     * Method: encodeSignedNumber
     * Encode one single signed integer and return an encoded string
     *
     * Parameters:
     * num - {int} A signed integer that should be encoded
     *
     * Returns:
     * {String} An encoded string
     */
    encodeSignedNumber: function (num) {
        var sgn_num = num << 1;
        if (num < 0)
            sgn_num = ~(sgn_num);
        return this.encodeNumber(sgn_num);
    },
    /**
     * Method: encodeNumber
     * Encode one single unsigned integer and return an encoded string
     *
     * encodeSignedNumber should be used instead of using this method directly!
     *
     * Parameters:
     * num - {int} An unsigned integer that should be encoded
     *
     * Returns:
     * {String} An encoded string
     */
    encodeNumber: function (num) {
        var encodeString = "";
        var value;
        while (num >= 0x20) {
            value = (0x20 | (num & 0x1f)) + 63;
            encodeString += (String.fromCharCode(value));
            num >>= 5;
        }
        value = num + 63;
        encodeString += (String.fromCharCode(value));
        return encodeString;
    },
    CLASS_NAME: "OpenLayers.Format.EncodedPolyline"
 });
@@ -91,6 +91,14 @@
        }
    }
    function test_Format_EncodedPolyline_encode(t) {
        t.plan(1);
        var format = new OpenLayers.Format.EncodedPolyline();
        t.eq(format.encode(basePoints, 2), encoded);
    }
    </script>
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