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Diffstat (limited to 'protected/extensions/egmap/EGMapPolylineEncoder.php')
| -rw-r--r-- | protected/extensions/egmap/EGMapPolylineEncoder.php | 248 |
1 files changed, 248 insertions, 0 deletions
diff --git a/protected/extensions/egmap/EGMapPolylineEncoder.php b/protected/extensions/egmap/EGMapPolylineEncoder.php new file mode 100644 index 0000000..23b2824 --- /dev/null +++ b/protected/extensions/egmap/EGMapPolylineEncoder.php @@ -0,0 +1,248 @@ +<?php +/** + * EGMapPolylineEncoder + * + * Modified version of: + * PolylineEncoder based on Mark McClure's Javascript PolylineEncoder + * and Jim Hribar's PHP version. All nicely melted into a proper PHP5 class. + * + * @package Google Maps Helpers + * @since 2008-12-02 + * @author Matthias Bauer <matthias@pulpmedia.at> + * @copyright 2008, Pulpmedia Medientechnik und -design GmbH + * @see http://facstaff.unca.edu/mcmcclur/GoogleMaps/EncodePolyline/ + */ +class EGMapPolylineEncoder { + + protected $numLevels = 18; + protected $zoomFactor = 2; + protected $verySmall = 0.00001; + protected $forceEndpoints = true; + protected $zoomLevelBreaks = array(); + + /** + * All parameters are set with useful defaults. + * If you actually want to understand them, see Mark McClure's detailed description. + * + * @see http://facstaff.unca.edu/mcmcclur/GoogleMaps/EncodePolyline/algorithm.html + */ + public function __construct($numLevels = 18, $zoomFactor = 2, $verySmall = 0.00001, $forceEndpoints = true) + { + $this->numLevels = $numLevels; + $this->zoomFactor = $zoomFactor; + $this->verySmall = $verySmall; + $this->forceEndpoints = $forceEndpoints; + + for ($i = 0; $i < $this->numLevels; $i++) + { + $this->zoomLevelBreaks[$i] = $this->verySmall * pow($this->zoomFactor, $this->numLevels - $i - 1); + } + } + + /** + * Generates all values needed for the encoded Google Maps Polyline. + * + * @param array Multidimensional input array in the form of + * array(array(latitude, longitude), array(latitude, longitude),...) + * + * @return String the encoded points | stdClass Simple object containing three public parameter: + * - points: the points string with escaped backslashes + * - levels: the encoded levels ready to use + * - rawPoints: the points right out of the encoder + * - numLevels: should be used for creating the polyline + * - zoomFactor: should be used for creating the polyline + */ + public function encode($points, $pointsOnly = true) + { + $absMaxDist=0; + $dists = array(); + if (count($points) > 2) + { + $stack[] = array(0, count($points) - 1); + while (count($stack) > 0) + { + $current = array_pop($stack); + $maxDist = 0; + for ($i = $current[0] + 1; $i < $current[1]; $i++) + { + $temp = $this->distance($points[$i], $points[$current[0]], $points[$current[1]]); + if ($temp > $maxDist) + { + $maxDist = $temp; + $maxLoc = $i; + if ($maxDist > $absMaxDist) + { + $absMaxDist = $maxDist; + } + } + } + if ($maxDist > $this->verySmall) + { + $dists[$maxLoc] = $maxDist; + array_push($stack, array($current[0], $maxLoc)); + array_push($stack, array($maxLoc, $current[1])); + } + } + } + + if ($pointsOnly) + return str_replace("\\","\\\\", $this->createEncodings($points, $dists)); + + $polyline = new stdClass(); + $polyline->rawPoints = $this->createEncodings($points, $dists); + $polyline->levels = $this->encodeLevels($points, $dists, $absMaxDist); + $polyline->points = str_replace("\\", "\\\\", $polyline->rawPoints); + $polyline->numLevels = $this->numLevels; + $polyline->zoomFactor = $this->zoomFactor; + + return $polyline; + } + /** + * + * @param integer $dd + * @return integer the computed level + */ + private function computeLevel($dd) + { + if ($dd > $this->verySmall) + { + $lev = 0; + while ($dd < $this->zoomLevelBreaks[$lev]) + { + $lev++; + } + } + return $lev; + } + /** + * Calculates distance between point locations + * + * @param integer $p0 + * @param integer $p1 + * @param integer $p2 + * @return integer + */ + private function distance($p0, $p1, $p2) + { + if ($p1[0] == $p2[0] && $p1[1] == $p2[1]) + { + $out = sqrt(pow($p2[0] - $p0[0], 2) + pow($p2[1] - $p0[1], 2)); + } else + { + $u = (($p0[0] - $p1[0]) * ($p2[0] - $p1[0]) + ($p0[1] - $p1[1]) * ($p2[1] - $p1[1])) / (pow($p2[0] - $p1[0], 2) + pow($p2[1] - $p1[1], 2)); + if ($u <= 0) + { + $out = sqrt(pow($p0[0] - $p1[0], 2) + pow($p0[1] - $p1[1], 2)); + } + if ($u >= 1) + { + $out = sqrt(pow($p0[0] - $p2[0], 2) + pow($p0[1] - $p2[1], 2)); + } + if (0 < $u && $u < 1) + { + $out = sqrt(pow($p0[0] - $p1[0] - $u * ($p2[0] - $p1[0]), 2) + pow($p0[1] - $p1[1] - $u * ($p2[1] - $p1[1]), 2)); + } + } + return $out; + } + /** + * Encodes a signed number + * + * @param float $num + * @return string + */ + private function encodeSignedNumber($num) + { + $sgn_num = $num << 1; + if ($num < 0) + { + $sgn_num = ~($sgn_num); + } + return $this->encodeNumber($sgn_num); + } + /** + * Encodes points + * @param array $points + * @param array $dists + * @return string the encoded points + */ + private function createEncodings($points, $dists) + { + $encoded_points = ''; + + $plat = $lng = $plng = $plat = 0; + for ($i = 0; $i < count($points); $i++) + { + if (isset($dists[$i]) || $i == 0 || $i == count($points) - 1) + { + $point = $points[$i]; + $lat = $point[0]; + $lng = $point[1]; + $late5 = floor($lat * 1e5); + $lnge5 = floor($lng * 1e5); + $dlat = $late5 - $plat; + $dlng = $lnge5 - $plng; + $plat = $late5; + $plng = $lnge5; + $encoded_points .= $this->encodeSignedNumber($dlat) . $this->encodeSignedNumber($dlng); + } + } + return $encoded_points; + } + /** + * Encodes levels + * + * @param array $points + * @param array $dists + * @param integer $absMaxDist + * @return string + */ + private function encodeLevels($points, $dists, $absMaxDist) + { + $encoded_levels = ''; + + if ($this->forceEndpoints) + { + $encoded_levels .= $this->encodeNumber($this->numLevels - 1); + } else + { + $encoded_levels .= $this->encodeNumber($this->numLevels - $this->computeLevel($absMaxDist) - 1); + } + for ($i = 1; $i < count($points) - 1; $i++) + { + if (isset($dists[$i])) + { + $encoded_levels .= $this->encodeNumber($this->numLevels - $this->computeLevel($dists[$i]) - 1); + } + } + if ($this->forceEndpoints) + { + $encoded_levels .= $this->encodeNumber($this->numLevels - 1); + } else + { + $encoded_levels .= $this->encodeNumber($this->numLevels - $this->computeLevel($absMaxDist) - 1); + } + return $encoded_levels; + } + /** + * Encodes a number + * + * @param integer $num + * @return string + */ + private function encodeNumber($num) + { + $encodeString = ''; + + while ($num >= 0x20) + { + $nextValue = (0x20 | ($num & 0x1f)) + 63; + $encodeString .= chr($nextValue); + $num >>= 5; + } + $finalValue = $num + 63; + $encodeString .= chr($finalValue); + return $encodeString; + } + +} |