OpenLayers 3.x API

To create OL 3 map with php you can use this code (from the openlayers_filters module):

//$map_name = your map name
$map = \Drupal\openlayers\Openlayers::load('map', $map_name);
$rendered = $map->render();

Additionally, some hooks can be found in the openlayers.api.php file of the docs folder of the openlayers module folder