HOG detector also must return the rectangles of the detections.

tests/dlib_face_detection.phpt

@@ -0,0 +1,18 @@
+--TEST--
+Frontal face detection.
+--SKIPIF--
+<?php if (!extension_loaded("pdlib") print "skip"; ?>
+--FILE--
+<?php
+printf("Detection\n");
+$detected_faces = dlib_face_detection(__DIR__ . "/lenna.jpg");
+printf("Faces found = %d\n", count($detected_faces));
+foreach($detected_faces as $index => $detected_face) {
+  printf("Face[%d] in bounding box (left=%d, top=%d, right=%d, bottom=%d)\n", $index,
+    $detected_face["left"], $detected_face["top"], $detected_face["right"], $detected_face["bottom"]);
+}
+?>
+--EXPECT--
+Detection
+Faces found = 1
+Face[0] in bounding box (left=214, top=194, right=393, bottom=373)