Add reference layer.

src/Netzmacht/Contao/Leaflet/Mapper/Layer/ReferenceLayerMapper.php

@@ -0,0 +1,45 @@
+<?php
+
+/**
+ * @package    dev
+ * @author     David Molineus <david.molineus@netzmacht.de>
+ * @copyright  2015 netzmacht creative David Molineus
+ * @license    LGPL 3.0
+ * @filesource
+ *
+ */
+
+namespace Netzmacht\Contao\Leaflet\Mapper\Layer;
+
+use Netzmacht\Contao\Leaflet\Mapper\DefinitionMapper;
+use Netzmacht\Contao\Leaflet\Model\LayerModel;
+use Netzmacht\LeafletPHP\Definition\Type\LatLngBounds;
+
+/**
+ * Class ReferenceLayerMapper maps an reference layer to another
+ *
+ * @package Netzmacht\Contao\Leaflet\Mapper\Layer
+ */
+class ReferenceLayerMapper extends AbstractLayerMapper
+{
+    /**
+     * Layer type.
+     *
+     * @var string
+     */
+    protected static $type = 'reference';
+
+    /**
+     * {@inheritdoc}
+     */
+    public function handle($model, DefinitionMapper $mapper, LatLngBounds $bounds = null, $elementId = null)
+    {
+        $reference = LayerModel::findByPk($model->reference);
+
+        if (!$reference || !$reference->active) {
+            return null;
+        }
+
+        return $mapper->handle($reference, $bounds, $this->getElementId($model, $elementId));
+    }
+}