[jsk_pcl_ros_utils][polygon_magnifier] allow negative param value

[jsk_pcl_ros_utils][polygon_magnifier] update docs

doc/jsk_pcl_ros_utils/nodes/polygon_magnifier.md

@@ -1,4 +1,7 @@
 # PolygonMagnifier
+
+![](./images/polygon_magnifier.png)
+
 Magnify polygons by specified length.
 
 ## Subscribing Topic
@@ -14,4 +17,4 @@ Magnify polygons by specified length.
 ## Parameters
 * `~magnify_distance` (Double, default: `0.2`)
 
-  Length to scale polygon
+  Length to scale polygons. Default value `0.2` means the distance of each corresponding edges will be `0.2` m.

jsk_pcl_ros_utils/cfg/PolygonMagnifier.cfg

@@ -9,5 +9,5 @@ from math import pi
 
 gen = ParameterGenerator ()
 
-gen.add("magnify_distance", double_t, 0, "Magnify distance", 0.2, 0.0, 10.0)
+gen.add("magnify_distance", double_t, 0, "Magnify distance", 0.2, -10.0, 10.0)
 exit (gen.generate (PACKAGE, "jsk_pcl_ros_utils", "PolygonMagnifier"))

jsk_pcl_ros_utils/src/polygon_magnifier_nodelet.cpp

@@ -72,8 +72,18 @@ namespace jsk_pcl_ros_utils
   {
     boost::mutex::scoped_lock lock(mutex_);
     vital_checker_->poke();
+
     jsk_recognition_msgs::PolygonArray ret_polygon_array;
     ret_polygon_array.header = msg->header;
+
+    ret_polygon_array.labels.reserve(msg->labels.size());
+    std::copy(msg->labels.begin(), msg->labels.end(),
+              std::back_inserter(ret_polygon_array.labels));
+
+    ret_polygon_array.likelihood.reserve(msg->likelihood.size());
+    std::copy(msg->likelihood.begin(), msg->likelihood.end(),
+              std::back_inserter(ret_polygon_array.likelihood));
+
     for (size_t i = 0; i < msg->polygons.size(); i++) {
       geometry_msgs::PolygonStamped magnified_polygon;
       magnified_polygon.header = msg->polygons[i].header;
@@ -84,7 +94,6 @@ namespace jsk_pcl_ros_utils
     }
     pub_.publish(ret_polygon_array);
   }
-
 }
 
 #include <pluginlib/class_list_macros.h>