Added service to set WhiteBalanceAuto mode to Once

CMakeLists.txt

@@ -46,6 +46,7 @@ add_service_files(
   get_float_feature_value.srv
   get_integer_feature_value.srv
   get_string_feature_value.srv
+  one_shot_white_balance.srv
   set_boolean_feature_value.srv
   set_float_feature_value.srv
   set_integer_feature_value.srv

README.md

@@ -146,6 +146,10 @@ specified in 'wb_ratio_selectors'. This list should be the same size as the rati
 	- Default: ```""```
 	- Example: ```"1.4,2.5"```
 
+To trigger an automatic white balance computation and a subsequent setting of ```BalanceWhiteAuto``` to ```Once```, camera_aravis provides a service called ```trigger_one_shot_white_balance```. 
+Calling this service will trigger a one shot computation of the white balance parameters and return the newly computed balance ratio.
+This can be called no matter which mode has been set previously.
+
 ### Activating PTP Timestamp
 
 Some cameras support the use of the Precision Time Protocol (PTP) to set the timestamps of the 

include/camera_aravis/camera_aravis_nodelet.h

@@ -74,6 +74,7 @@ extern "C" {
 #include <camera_aravis/set_string_feature_value.h>
 #include <camera_aravis/get_boolean_feature_value.h>
 #include <camera_aravis/set_boolean_feature_value.h>
+#include <camera_aravis/one_shot_white_balance.h>
 
 #include <camera_aravis/camera_buffer_pool.h>
 #include <camera_aravis/conversion_utils.h>
@@ -171,6 +172,9 @@ class CameraAravisNodelet : public nodelet::Nodelet
   ros::ServiceServer set_boolean_service_;
   bool setBooleanFeatureCallback(camera_aravis::set_boolean_feature_value::Request& request, camera_aravis::set_boolean_feature_value::Response& response);
 
+  ros::ServiceServer one_shot_white_balance_service_;
+  bool oneShotWhiteBalanceCallback(camera_aravis::one_shot_white_balance::Request& request, camera_aravis::one_shot_white_balance::Response& response);
+
   // triggers a shot at regular intervals, sleeps in between
   void softwareTriggerLoop();
 

src/camera_aravis_nodelet.cpp

@@ -677,6 +677,8 @@ void CameraAravisNodelet::spawnStream()
     this->set_string_service_  = pnh.advertiseService("set_string_feature_value", &CameraAravisNodelet::setStringFeatureCallback, this);
     this->set_boolean_service_ = pnh.advertiseService("set_boolean_feature_value", &CameraAravisNodelet::setBooleanFeatureCallback, this);
 
+    this->one_shot_white_balance_service_ = pnh.advertiseService("trigger_one_shot_white_balance", &CameraAravisNodelet::oneShotWhiteBalanceCallback, this);
+
     ROS_INFO("Done initializing camera_aravis.");
 }
 
@@ -772,6 +774,59 @@ bool CameraAravisNodelet::setBooleanFeatureCallback(camera_aravis::set_boolean_f
     return true;
 }
 
+bool CameraAravisNodelet::oneShotWhiteBalanceCallback(camera_aravis::one_shot_white_balance::Request& request, camera_aravis::one_shot_white_balance::Response& response)
+{
+    //--- set return values to default
+    response.is_successful = false;
+    response.balance_ratio_red = 0.f;
+    response.balance_ratio_green = 0.f;
+    response.balance_ratio_blue = 0.f;
+
+    //--- check for correct state of camera
+    if(!this->p_device_ || !implemented_features_["BalanceWhiteAuto"])
+        return false;
+
+    arv_device_set_string_feature_value(p_device_, "BalanceWhiteAuto", "Once");
+    if (arv_device_get_status(this->p_device_) == ARV_DEVICE_STATUS_SUCCESS)
+    {
+        const char* tmpCharPtr = arv_device_get_string_feature_value(p_device_, "BalanceWhiteAuto");
+        std::string modeStr = "n/a";
+        if(tmpCharPtr)
+            modeStr = std::string(tmpCharPtr);
+
+        if (implemented_features_["BalanceRatio"] && implemented_features_["BalanceRatioSelector"])
+        {
+            arv_device_set_string_feature_value(p_device_, "BalanceRatioSelector", "Red");
+            response.balance_ratio_red = static_cast<float>(
+                arv_device_get_float_feature_value(p_device_, "BalanceRatio"));
+
+            arv_device_set_string_feature_value(p_device_, "BalanceRatioSelector", "Green");
+            response.balance_ratio_green = static_cast<float>(
+                arv_device_get_float_feature_value(p_device_, "BalanceRatio"));
+
+            arv_device_set_string_feature_value(p_device_, "BalanceRatioSelector", "Blue");
+            response.balance_ratio_blue = static_cast<float>(
+                arv_device_get_float_feature_value(p_device_, "BalanceRatio"));
+        }
+
+        ROS_INFO("Setting Auto White Balance successful!");
+        ROS_INFO("> BalanceWhiteAuto Mode:   %s", modeStr.c_str());
+        ROS_INFO("> BalanceRatio     Red:    %f", response.balance_ratio_red);
+        ROS_INFO("> BalanceRatio     Green:  %f", response.balance_ratio_green);
+        ROS_INFO("> BalanceRatio     Blue:   %f", response.balance_ratio_blue);
+
+
+        response.is_successful = true;
+        return true;
+    }
+    else
+    {
+        ROS_ERROR("Trying to set Auto White Balance once failed!");
+
+        return false;
+    }
+}
+
 void CameraAravisNodelet::resetPtpClock()
 {
     if (ptp_status_feature_.empty() || ptp_enable_feature_.empty())

srv/one_shot_white_balance.srv

@@ -0,0 +1,5 @@
+---
+bool is_successful
+float32 balance_ratio_red
+float32 balance_ratio_green
+float32 balance_ratio_blue