Hi All,
I've just written a small shared-memory based image_transport_plugin
using boost::interprocess and it raises 2 questions:
- First, I don't see how to write it efficiently while having the
publish function const in image_transport/publisher.h. I currently wait
to receive the first image to allocate the shared memory segment, and as
far as I could tell, I can only do it in the publish function of the
plugin, so this has to be non-const. Any reason why it would have to be
const? Or any hint on how to achieve the same result while having the
function const?
- Second, as it is written now, the plugin does not care at all that the
object it manipulates are images (it cares that the object are
constant/bounded size though). So would it be possible to extend/convert
the image_transport plugin architecture, to a generic message_transport
plugin architecture? I think sharedmem transfer would be particularly
suitable for big point clouds...
I attach the targz of the package if someone wants to review it. It will
NOT compile in a standard install, because of the "const" problem
mentioned above. I include a patch to image_transport that removes the
"const". Note that if you apply it, you also need to check the const in
the other image_transport_plugins (2nd patch).
Best,
--
Dr. Cedric Pradalier
http://www.asl.ethz.ch/people/cedricp
Index: include/image_transport/publisher.h
===================================================================
--- include/image_transport/publisher.h (revision 29372)
+++ include/image_transport/publisher.h (working copy)
@@ -79,12 +79,12 @@
/*!
* \brief Publish an image on the topics associated with this Publisher.
*/
- void publish(const sensor_msgs::Image& message) const;
+ void publish(const sensor_msgs::Image& message) ;
/*!
* \brief Publish an image on the topics associated with this Publisher.
*/
- void publish(const sensor_msgs::ImageConstPtr& message) const;
+ void publish(const sensor_msgs::ImageConstPtr& message) ;
/*!
* \brief Shutdown the advertisements associated with this Publisher.
Index: include/image_transport/raw_publisher.h
===================================================================
--- include/image_transport/raw_publisher.h (revision 29372)
+++ include/image_transport/raw_publisher.h (working copy)
@@ -22,7 +22,7 @@
}
protected:
- virtual void publish(const sensor_msgs::Image& message, const PublishFn& publish_fn) const
+ virtual void publish(const sensor_msgs::Image& message, const PublishFn& publish_fn)
{
publish_fn(message);
}
Index: include/image_transport/publisher_plugin.h
===================================================================
--- include/image_transport/publisher_plugin.h (revision 29372)
+++ include/image_transport/publisher_plugin.h (working copy)
@@ -56,12 +56,12 @@
/**
* \brief Publish an image using the transport associated with this PublisherPlugin.
*/
- virtual void publish(const sensor_msgs::Image& message) const = 0;
+ virtual void publish(const sensor_msgs::Image& message) = 0;
/**
* \brief Publish an image using the transport associated with this PublisherPlugin.
*/
- virtual void publish(const sensor_msgs::ImageConstPtr& message) const
+ virtual void publish(const sensor_msgs::ImageConstPtr& message)
{
publish(*message);
}
Index: include/image_transport/simple_publisher_plugin.h
===================================================================
--- include/image_transport/simple_publisher_plugin.h (revision 29372)
+++ include/image_transport/simple_publisher_plugin.h (working copy)
@@ -41,7 +41,7 @@
return std::string();
}
- virtual void publish(const sensor_msgs::Image& message) const
+ virtual void publish(const sensor_msgs::Image& message)
{
if (!simple_impl_ || !simple_impl_->pub_) {
ROS_ASSERT_MSG(false, "Call to publish() on an invalid image_transport::SimplePublisherPlugin");
@@ -82,7 +82,7 @@
* SimpleSubscriberPlugin to use this function for both normal broadcast publishing and
* single subscriber publishing (in subscription callbacks).
*/
- virtual void publish(const sensor_msgs::Image& message, const PublishFn& publish_fn) const = 0;
+ virtual void publish(const sensor_msgs::Image& message, const PublishFn& publish_fn) = 0;
/**
* \brief Return the communication topic name for a given base topic.
@@ -161,7 +161,7 @@
// Construct a function object for publishing sensor_msgs::Image through the
// subclass-implemented publish() using the ros::SingleSubscriberPublisher to send
// messages of the transport-specific type.
- typedef void (SimplePublisherPlugin::*PublishMemFn)(const sensor_msgs::Image&, const PublishFn&) const;
+ typedef void (SimplePublisherPlugin::*PublishMemFn)(const sensor_msgs::Image&, const PublishFn&) ;
PublishMemFn pub_mem_fn = &SimplePublisherPlugin::publish;
ImagePublishFn image_publish_fn = boost::bind(pub_mem_fn, this, _1, bindInternalPublisher(ros_ssp));
Index: src/publisher.cpp
===================================================================
--- src/publisher.cpp (revision 29372)
+++ src/publisher.cpp (working copy)
@@ -137,27 +137,27 @@
return std::string();
}
-void Publisher::publish(const sensor_msgs::Image& message) const
+void Publisher::publish(const sensor_msgs::Image& message)
{
if (!impl_ || !impl_->isValid()) {
ROS_ASSERT_MSG(false, "Call to publish() on an invalid image_transport::Publisher");
return;
}
- BOOST_FOREACH(const PublisherPlugin& pub, impl_->publishers_) {
+ BOOST_FOREACH(PublisherPlugin& pub, impl_->publishers_) {
if (pub.getNumSubscribers() > 0)
pub.publish(message);
}
}
-void Publisher::publish(const sensor_msgs::ImageConstPtr& message) const
+void Publisher::publish(const sensor_msgs::ImageConstPtr& message)
{
if (!impl_ || !impl_->isValid()) {
ROS_ASSERT_MSG(false, "Call to publish() on an invalid image_transport::Publisher");
return;
}
- BOOST_FOREACH(const PublisherPlugin& pub, impl_->publishers_) {
+ BOOST_FOREACH(PublisherPlugin& pub, impl_->publishers_) {
if (pub.getNumSubscribers() > 0)
pub.publish(message);
}
Index: src/republish.cpp
===================================================================
--- src/republish.cpp (revision 29372)
+++ src/republish.cpp (working copy)
@@ -22,7 +22,7 @@
image_transport::Publisher pub = it.advertise(out_topic, 1);
// Use Publisher::publish as the subscriber callback
- typedef void (image_transport::Publisher::*PublishMemFn)(const sensor_msgs::ImageConstPtr&) const;
+ typedef void (image_transport::Publisher::*PublishMemFn)(const sensor_msgs::ImageConstPtr&) ;
PublishMemFn pub_mem_fn = &image_transport::Publisher::publish;
sub = it.subscribe(in_topic, 1, boost::bind(pub_mem_fn, &pub, _1), ros::VoidPtr(), in_transport);
@@ -41,7 +41,7 @@
image_transport::SubscriberStatusCallback(), ros::VoidPtr(), false);
// Use PublisherPlugin::publish as the subscriber callback
- typedef void (Plugin::*PublishMemFn)(const sensor_msgs::ImageConstPtr&) const;
+ typedef void (Plugin::*PublishMemFn)(const sensor_msgs::ImageConstPtr&) ;
PublishMemFn pub_mem_fn = &Plugin::publish;
sub = it.subscribe(in_topic, 1, boost::bind(pub_mem_fn, pub.get(), _1), pub, in_transport);
Index: theora_image_transport/include/theora_image_transport/theora_publisher.h
===================================================================
--- theora_image_transport/include/theora_image_transport/theora_publisher.h (revision 29372)
+++ theora_image_transport/include/theora_image_transport/theora_publisher.h (working copy)
@@ -28,7 +28,7 @@
//Main publish function
virtual void publish(const sensor_msgs::Image& message,
- const PublishFn& publish_fn) const;
+ const PublishFn& publish_fn) ;
private:
//Utility functions
Index: theora_image_transport/src/theora_publisher.cpp
===================================================================
--- theora_image_transport/src/theora_publisher.cpp (revision 29372)
+++ theora_image_transport/src/theora_publisher.cpp (working copy)
@@ -36,7 +36,7 @@
}
}
-void TheoraPublisher::publish(const sensor_msgs::Image& message, const PublishFn& publish_fn) const
+void TheoraPublisher::publish(const sensor_msgs::Image& message, const PublishFn& publish_fn)
{
if (img_bridge_.fromImage(message, "bgr8"))
{
Index: compressed_image_transport/include/compressed_image_transport/compressed_publisher.h
===================================================================
--- compressed_image_transport/include/compressed_image_transport/compressed_publisher.h (revision 29372)
+++ compressed_image_transport/include/compressed_image_transport/compressed_publisher.h (working copy)
@@ -15,7 +15,7 @@
protected:
virtual void publish(const sensor_msgs::Image& message,
- const PublishFn& publish_fn) const;
+ const PublishFn& publish_fn) ;
};
} //namespace compressed_image_transport
Index: compressed_image_transport/src/compressed_publisher.cpp
===================================================================
--- compressed_image_transport/src/compressed_publisher.cpp (revision 29372)
+++ compressed_image_transport/src/compressed_publisher.cpp (working copy)
@@ -6,7 +6,7 @@
namespace compressed_image_transport {
void CompressedPublisher::publish(const sensor_msgs::Image& message,
- const PublishFn& publish_fn) const
+ const PublishFn& publish_fn)
{
// View/convert as mono or RGB
sensor_msgs::CvBridge bridge;
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