PHP 坐标位于多边形内

/**
 * 判断坐标是否在坐标区间范围内
 *
 * @param  array  $check_point  判断坐标
 * @param  array  $polygon_points  坐标区间范围
 * @return bool
 */
function is_in_polygon(array $check_point, array $polygon_points) {
    $counter = 0;
    $p1 = $polygon_points[0];
    $point_count = count($polygon_points);

    for($i = 1; $i <= $point_count; $i++) {
        $p2 = $polygon_points[$i % $point_count];
        if (
            $check_point[0] > min($p1[0], $p2[0]) &&
            $check_point[0] <= max($p1[0], $p2[0])
        ) {
            if ($check_point[1] <= max($p1[1], $p2[1])) {
                if ($p1[0] != $p2[0]) {
                    $xinters =
                        ($check_point[0] - $p1[0]) *
                            ($p2[1] - $p1[1]) /
                            ($p2[0] - $p1[0]) +
                        $p1[1];
                    if ($p1[1] == $p2[1] || $check_point[1] <= $xinters) {
                        $counter++;
                    }
                }
            }
        }
    }

    return $counter % 2 != 0;
}

// -------------------------
// 测试
// 在范围内返回 true
is_in_polygon(
    [113.27239573001862, 23.09122994009315],
    [
        [113.2675838470459, 23.09250306837517],
        [113.2714033126831, 23.08877247232314],
        [113.27876329421997, 23.093095216954744],
        [113.2675838470459, 23.09250306837517]
    ]
);

// 在不范围内返回 false
is_in_polygon(
    [113.27332377433777, 23.093411028463525],
    [
        [113.2675838470459, 23.09250306837517],
        [113.2714033126831, 23.08877247232314],
        [113.27876329421997, 23.093095216954744],
        [113.2675838470459, 23.09250306837517]
    ]
);