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<?php
/* vim: set expandtab sw=4 ts=4 sts=4: */
/**
* Handles actions related to GIS POLYGON objects
*
* @package PhpMyAdmin-GIS
*/
if (! defined('PHPMYADMIN')) {
exit;
}
/**
* Handles actions related to GIS POLYGON objects
*
* @package PhpMyAdmin-GIS
*/
class PMA_GIS_Polygon extends PMA_GIS_Geometry
{
// Hold the singleton instance of the class
private static $_instance;
/**
* A private constructor; prevents direct creation of object.
*
* @access private
*/
private function __construct()
{
}
/**
* Returns the singleton.
*
* @return PMA_GIS_Polygon the singleton
* @access public
*/
public static function singleton()
{
if (!isset(self::$_instance)) {
$class = __CLASS__;
self::$_instance = new $class;
}
return self::$_instance;
}
/**
* Scales each row.
*
* @param string $spatial spatial data of a row
*
* @return array an array containing the min, max values for x and y cordinates
* @access public
*/
public function scaleRow($spatial)
{
// Trim to remove leading 'POLYGON((' and trailing '))'
$polygon = substr($spatial, 9, (strlen($spatial) - 11));
// If the polygon doesn't have an inner ring, use polygon itself
if (strpos($polygon, "),(") === false) {
$ring = $polygon;
} else {
// Seperate outer ring and use it to determin min-max
$parts = explode("),(", $polygon);
$ring = $parts[0];
}
return $this->setMinMax($ring, array());
}
/**
* Adds to the PNG image object, the data related to a row in the GIS dataset.
*
* @param string $spatial GIS POLYGON object
* @param string $label Label for the GIS POLYGON object
* @param string $fill_color Color for the GIS POLYGON object
* @param array $scale_data Array containing data related to scaling
* @param resource $image Image object
*
* @return object the modified image object
* @access public
*/
public function prepareRowAsPng($spatial, $label, $fill_color,
$scale_data, $image
) {
// allocate colors
$black = imagecolorallocate($image, 0, 0, 0);
$red = hexdec(substr($fill_color, 1, 2));
$green = hexdec(substr($fill_color, 3, 2));
$blue = hexdec(substr($fill_color, 4, 2));
$color = imagecolorallocate($image, $red, $green, $blue);
// Trim to remove leading 'POLYGON((' and trailing '))'
$polygon = substr($spatial, 9, (strlen($spatial) - 11));
// If the polygon doesnt have an inner polygon
if (strpos($polygon, "),(") === false) {
$points_arr = $this->extractPoints($polygon, $scale_data, true);
} else {
// Seperate outer and inner polygons
$parts = explode("),(", $polygon);
$outer = $parts[0];
$inner = array_slice($parts, 1);
$points_arr = $this->extractPoints($outer, $scale_data, true);
foreach ($inner as $inner_poly) {
$points_arr = array_merge(
$points_arr, $this->extractPoints($inner_poly, $scale_data, true)
);
}
}
// draw polygon
imagefilledpolygon($image, $points_arr, sizeof($points_arr) / 2, $color);
// print label if applicable
if (isset($label) && trim($label) != '') {
imagestring(
$image, 1, $points_arr[2], $points_arr[3], trim($label), $black
);
}
return $image;
}
/**
* Adds to the TCPDF instance, the data related to a row in the GIS dataset.
*
* @param string $spatial GIS POLYGON object
* @param string $label Label for the GIS POLYGON object
* @param string $fill_color Color for the GIS POLYGON object
* @param array $scale_data Array containing data related to scaling
* @param TCPDF $pdf TCPDF instance
*
* @return TCPDF the modified TCPDF instance
* @access public
*/
public function prepareRowAsPdf($spatial, $label, $fill_color, $scale_data, $pdf)
{
// allocate colors
$red = hexdec(substr($fill_color, 1, 2));
$green = hexdec(substr($fill_color, 3, 2));
$blue = hexdec(substr($fill_color, 4, 2));
$color = array($red, $green, $blue);
// Trim to remove leading 'POLYGON((' and trailing '))'
$polygon = substr($spatial, 9, (strlen($spatial) - 11));
// If the polygon doesnt have an inner polygon
if (strpos($polygon, "),(") === false) {
$points_arr = $this->extractPoints($polygon, $scale_data, true);
} else {
// Seperate outer and inner polygons
$parts = explode("),(", $polygon);
$outer = $parts[0];
$inner = array_slice($parts, 1);
$points_arr = $this->extractPoints($outer, $scale_data, true);
foreach ($inner as $inner_poly) {
$points_arr = array_merge(
$points_arr, $this->extractPoints($inner_poly, $scale_data, true)
);
}
}
// draw polygon
$pdf->Polygon($points_arr, 'F*', array(), $color, true);
// print label if applicable
if (isset($label) && trim($label) != '') {
$pdf->SetXY($points_arr[2], $points_arr[3]);
$pdf->SetFontSize(5);
$pdf->Cell(0, 0, trim($label));
}
return $pdf;
}
/**
* Prepares and returns the code related to a row in the GIS dataset as SVG.
*
* @param string $spatial GIS POLYGON object
* @param string $label Label for the GIS POLYGON object
* @param string $fill_color Color for the GIS POLYGON object
* @param array $scale_data Array containing data related to scaling
*
* @return string the code related to a row in the GIS dataset
* @access public
*/
public function prepareRowAsSvg($spatial, $label, $fill_color, $scale_data)
{
$polygon_options = array(
'name' => $label,
'id' => $label . rand(),
'class' => 'polygon vector',
'stroke' => 'black',
'stroke-width'=> 0.5,
'fill' => $fill_color,
'fill-rule' => 'evenodd',
'fill-opacity'=> 0.8,
);
// Trim to remove leading 'POLYGON((' and trailing '))'
$polygon = substr($spatial, 9, (strlen($spatial) - 11));
$row = '<path d="';
// If the polygon doesnt have an inner polygon
if (strpos($polygon, "),(") === false) {
$row .= $this->_drawPath($polygon, $scale_data);
} else {
// Seperate outer and inner polygons
$parts = explode("),(", $polygon);
$outer = $parts[0];
$inner = array_slice($parts, 1);
$row .= $this->_drawPath($outer, $scale_data);
foreach ($inner as $inner_poly) {
$row .= $this->_drawPath($inner_poly, $scale_data);
}
}
$row .= '"';
foreach ($polygon_options as $option => $val) {
$row .= ' ' . $option . '="' . trim($val) . '"';
}
$row .= '/>';
return $row;
}
/**
* Prepares JavaScript related to a row in the GIS dataset
* to visualize it with OpenLayers.
*
* @param string $spatial GIS POLYGON object
* @param int $srid Spatial reference ID
* @param string $label Label for the GIS POLYGON object
* @param string $fill_color Color for the GIS POLYGON object
* @param array $scale_data Array containing data related to scaling
*
* @return string JavaScript related to a row in the GIS dataset
* @access public
*/
public function prepareRowAsOl($spatial, $srid, $label, $fill_color, $scale_data)
{
$style_options = array(
'strokeColor' => '#000000',
'strokeWidth' => 0.5,
'fillColor' => $fill_color,
'fillOpacity' => 0.8,
'label' => $label,
'fontSize' => 10,
);
if ($srid == 0) {
$srid = 4326;
}
$row = $this->getBoundsForOl($srid, $scale_data);
// Trim to remove leading 'POLYGON((' and trailing '))'
$polygon = substr($spatial, 9, (strlen($spatial) - 11));
// Seperate outer and inner polygons
$parts = explode("),(", $polygon);
$row .= 'vectorLayer.addFeatures(new OpenLayers.Feature.Vector('
. $this->getPolygonForOpenLayers($parts, $srid)
. ', null, ' . json_encode($style_options) . '));';
return $row;
}
/**
* Draws a ring of the polygon using SVG path element.
*
* @param string $polygon The ring
* @param array $scale_data Array containing data related to scaling
*
* @return string the code to draw the ring
* @access private
*/
private function _drawPath($polygon, $scale_data)
{
$points_arr = $this->extractPoints($polygon, $scale_data);
$row = ' M ' . $points_arr[0][0] . ', ' . $points_arr[0][1];
$other_points = array_slice($points_arr, 1, count($points_arr) - 2);
foreach ($other_points as $point) {
$row .= ' L ' . $point[0] . ', ' . $point[1];
}
$row .= ' Z ';
return $row;
}
/**
* Generate the WKT with the set of parameters passed by the GIS editor.
*
* @param array $gis_data GIS data
* @param int $index Index into the parameter object
* @param string $empty Value for empty points
*
* @return string WKT with the set of parameters passed by the GIS editor
* @access public
*/
public function generateWkt($gis_data, $index, $empty = '')
{
$no_of_lines = isset($gis_data[$index]['POLYGON']['no_of_lines'])
? $gis_data[$index]['POLYGON']['no_of_lines'] : 1;
if ($no_of_lines < 1) {
$no_of_lines = 1;
}
$wkt = 'POLYGON(';
for ($i = 0; $i < $no_of_lines; $i++) {
$no_of_points = isset($gis_data[$index]['POLYGON'][$i]['no_of_points'])
? $gis_data[$index]['POLYGON'][$i]['no_of_points'] : 4;
if ($no_of_points < 4) {
$no_of_points = 4;
}
$wkt .= '(';
for ($j = 0; $j < $no_of_points; $j++) {
$wkt .= ((isset($gis_data[$index]['POLYGON'][$i][$j]['x'])
&& trim($gis_data[$index]['POLYGON'][$i][$j]['x']) != '')
? $gis_data[$index]['POLYGON'][$i][$j]['x'] : $empty)
. ' ' . ((isset($gis_data[$index]['POLYGON'][$i][$j]['y'])
&& trim($gis_data[$index]['POLYGON'][$i][$j]['y']) != '')
? $gis_data[$index]['POLYGON'][$i][$j]['y'] : $empty) . ',';
}
$wkt = substr($wkt, 0, strlen($wkt) - 1);
$wkt .= '),';
}
$wkt = substr($wkt, 0, strlen($wkt) - 1);
$wkt .= ')';
return $wkt;
}
/**
* Calculates the area of a closed simple polygon.
*
* @param array $ring array of points forming the ring
*
* @return float the area of a closed simple polygon
* @access public
* @static
*/
public static function area($ring)
{
$no_of_points = count($ring);
// If the last point is same as the first point ignore it
$last = count($ring) - 1;
if (($ring[0]['x'] == $ring[$last]['x'])
&& ($ring[0]['y'] == $ring[$last]['y'])
) {
$no_of_points--;
}
// _n-1
// A = _1_ \ (X(i) * Y(i+1)) - (Y(i) * X(i+1))
// 2 /__
// i=0
$area = 0;
for ($i = 0; $i < $no_of_points; $i++) {
$j = ($i + 1) % $no_of_points;
$area += $ring[$i]['x'] * $ring[$j]['y'];
$area -= $ring[$i]['y'] * $ring[$j]['x'];
}
$area /= 2.0;
return $area;
}
/**
* Determines whether a set of points represents an outer ring.
* If points are in clockwise orientation then, they form an outer ring.
*
* @param array $ring array of points forming the ring
*
* @return bool whether a set of points represents an outer ring
* @access public
* @static
*/
public static function isOuterRing($ring)
{
// If area is negative then it's in clockwise orientation,
// i.e. it's an outer ring
if (PMA_GIS_Polygon::area($ring) < 0) {
return true;
}
return false;
}
/**
* Determines whether a given point is inside a given polygon.
*
* @param array $point x, y coordinates of the point
* @param array $polygon array of points forming the ring
*
* @return bool whether a given point is inside a given polygon
* @access public
* @static
*/
public static function isPointInsidePolygon($point, $polygon)
{
// If first point is repeated at the end remove it
$last = count($polygon) - 1;
if (($polygon[0]['x'] == $polygon[$last]['x'])
&& ($polygon[0]['y'] == $polygon[$last]['y'])
) {
$polygon = array_slice($polygon, 0, $last);
}
$no_of_points = count($polygon);
$counter = 0;
// Use ray casting algorithm
$p1 = $polygon[0];
for ($i = 1; $i <= $no_of_points; $i++) {
$p2 = $polygon[$i % $no_of_points];
if ($point['y'] <= min(array($p1['y'], $p2['y']))) {
$p1 = $p2;
continue;
}
if ($point['y'] > max(array($p1['y'], $p2['y']))) {
$p1 = $p2;
continue;
}
if ($point['x'] > max(array($p1['x'], $p2['x']))) {
$p1 = $p2;
continue;
}
if ($p1['y'] != $p2['y']) {
$xinters = ($point['y'] - $p1['y'])
* ($p2['x'] - $p1['x'])
/ ($p2['y'] - $p1['y']) + $p1['x'];
if ($p1['x'] == $p2['x'] || $point['x'] <= $xinters) {
$counter++;
}
}
$p1 = $p2;
}
if ($counter % 2 == 0) {
return false;
} else {
return true;
}
}
/**
* Returns a point that is guaranteed to be on the surface of the ring.
* (for simple closed rings)
*
* @param array $ring array of points forming the ring
*
* @return array|void a point on the surface of the ring
* @access public
* @static
*/
public static function getPointOnSurface($ring)
{
// Find two consecutive distinct points.
for ($i = 0, $nb = count($ring) - 1; $i < $nb; $i++) {
if ($ring[$i]['y'] != $ring[$i + 1]['y']) {
$x0 = $ring[$i]['x'];
$x1 = $ring[$i + 1]['x'];
$y0 = $ring[$i]['y'];
$y1 = $ring[$i + 1]['y'];
break;
}
}
if (! isset($x0)) {
return false;
}
// Find the mid point
$x2 = ($x0 + $x1) / 2;
$y2 = ($y0 + $y1) / 2;
// Always keep $epsilon < 1 to go with the reduction logic down here
$epsilon = 0.1;
$denominator = sqrt(
PMA_Util::pow(($y1 - $y0), 2)
+ PMA_Util::pow(($x0 - $x1), 2)
);
$pointA = array(); $pointB = array();
while (true) {
// Get the points on either sides of the line
// with a distance of epsilon to the mid point
$pointA['x'] = $x2 + ($epsilon * ($y1 - $y0)) / $denominator;
$pointA['y'] = $y2 + ($pointA['x'] - $x2) * ($x0 - $x1) / ($y1 - $y0);
$pointB['x'] = $x2 + ($epsilon * ($y1 - $y0)) / (0 - $denominator);
$pointB['y'] = $y2 + ($pointB['x'] - $x2) * ($x0 - $x1) / ($y1 - $y0);
// One of the points should be inside the polygon,
// unless epcilon chosen is too large
if (PMA_GIS_Polygon::isPointInsidePolygon($pointA, $ring)) {
return $pointA;
} elseif (PMA_GIS_Polygon::isPointInsidePolygon($pointB, $ring)) {
return $pointB;
} else {
//If both are outside the polygon reduce the epsilon and
//recalculate the points(reduce exponentially for faster convergance)
$epsilon = PMA_Util::pow($epsilon, 2);
if ($epsilon == 0) {
return false;
}
}
}
}
/** Generate parameters for the GIS data editor from the value of the GIS column.
*
* @param string $value Value of the GIS column
* @param int $index Index of the geometry
*
* @return array params for the GIS data editor from the value of the GIS column
* @access public
*/
public function generateParams($value, $index = -1)
{
$params = array();
if ($index == -1) {
$index = 0;
$data = PMA_GIS_Geometry::generateParams($value);
$params['srid'] = $data['srid'];
$wkt = $data['wkt'];
} else {
$params[$index]['gis_type'] = 'POLYGON';
$wkt = $value;
}
// Trim to remove leading 'POLYGON((' and trailing '))'
$polygon = substr($wkt, 9, (strlen($wkt) - 11));
// Seperate each linestring
$linerings = explode("),(", $polygon);
$params[$index]['POLYGON']['no_of_lines'] = count($linerings);
$j = 0;
foreach ($linerings as $linering) {
$points_arr = $this->extractPoints($linering, null);
$no_of_points = count($points_arr);
$params[$index]['POLYGON'][$j]['no_of_points'] = $no_of_points;
for ($i = 0; $i < $no_of_points; $i++) {
$params[$index]['POLYGON'][$j][$i]['x'] = $points_arr[$i][0];
$params[$index]['POLYGON'][$j][$i]['y'] = $points_arr[$i][1];
}
$j++;
}
return $params;
}
}
?>
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