A Class which provides coordinate transforms between any two frames in a system. More...

#include <buffer_core.h>

Classes
struct	RemoveRequestByCallback
struct	RemoveRequestByID
struct	TransformableRequest
Public Types
typedef boost::function< void(TransformableRequestHandle request_handle, const std::string &target_frame, const std::string &source_frame, ros::Time time, TransformableResult result)>	TransformableCallback
Public Member Functions
boost::signals2::connection	_addTransformsChangedListener (boost::function< void(void)> callback)
	Add a callback that happens when a new transform has arrived.
std::string	_allFramesAsDot (double current_time) const
	Backwards compatabilityA way to see what frames have been cached Useful for debugging.
std::string	_allFramesAsDot () const
void	_chainAsVector (const std::string &target_frame, ros::Time target_time, const std::string &source_frame, ros::Time source_time, const std::string &fixed_frame, std::vector< std::string > &output) const
	Backwards compatabilityA way to see what frames are in a chain Useful for debugging.
bool	_frameExists (const std::string &frame_id_str) const
	Check if a frame exists in the tree.
void	_getFrameStrings (std::vector< std::string > &ids) const
	A way to get a std::vector of available frame ids.
int	_getLatestCommonTime (CompactFrameID target_frame, CompactFrameID source_frame, ros::Time &time, std::string *error_string) const
bool	_getParent (const std::string &frame_id, ros::Time time, std::string &parent) const
	Fill the parent of a frame.
CompactFrameID	_lookupFrameNumber (const std::string &frameid_str) const
CompactFrameID	_lookupOrInsertFrameNumber (const std::string &frameid_str)
void	_removeTransformsChangedListener (boost::signals2::connection c)
CompactFrameID	_validateFrameId (const char *function_name_arg, const std::string &frame_id) const
TransformableCallbackHandle	addTransformableCallback (const TransformableCallback &cb)
	Internal use only.
TransformableRequestHandle	addTransformableRequest (TransformableCallbackHandle handle, const std::string &target_frame, const std::string &source_frame, ros::Time time)
	Internal use only.
std::string	allFramesAsString () const
	A way to see what frames have been cached Useful for debugging.
std::string	allFramesAsYAML (double current_time) const
	A way to see what frames have been cached in yaml format Useful for debugging tools.
std::string	allFramesAsYAML () const
	BufferCore (ros::Duration cache_time_=ros::Duration(DEFAULT_CACHE_TIME))
void	cancelTransformableRequest (TransformableRequestHandle handle)
	Internal use only.
bool	canTransform (const std::string &target_frame, const std::string &source_frame, const ros::Time &time, std::string *error_msg=NULL) const
	Lookup the twist of the tracking_frame with respect to the observation frame in the reference_frame using the reference point.
bool	canTransform (const std::string &target_frame, const ros::Time &target_time, const std::string &source_frame, const ros::Time &source_time, const std::string &fixed_frame, std::string *error_msg=NULL) const
	Test if a transform is possible.
void	clear ()
	Clear all data.
ros::Duration	getCacheLength ()
	Get the duration over which this transformer will cache.
bool	isUsingDedicatedThread () const
geometry_msgs::TransformStamped	lookupTransform (const std::string &target_frame, const std::string &source_frame, const ros::Time &time) const
	Get the transform between two frames by frame ID.
geometry_msgs::TransformStamped	lookupTransform (const std::string &target_frame, const ros::Time &target_time, const std::string &source_frame, const ros::Time &source_time, const std::string &fixed_frame) const
	Get the transform between two frames by frame ID assuming fixed frame.
void	removeTransformableCallback (TransformableCallbackHandle handle)
	Internal use only.
bool	setTransform (const geometry_msgs::TransformStamped &transform, const std::string &authority, bool is_static=false)
	Add transform information to the tf data structure.
void	setUsingDedicatedThread (bool value)
virtual	~BufferCore (void)
Static Public Attributes
static const int	DEFAULT_CACHE_TIME = 10
	The default amount of time to cache data in seconds.
static const uint32_t	MAX_GRAPH_DEPTH = 1000UL
	Maximum graph search depth (deeper graphs will be assumed to have loops)
Private Types
typedef boost::unordered_map < std::string, CompactFrameID >	M_StringToCompactFrameID
	A map from string frame ids to CompactFrameID.
typedef boost::unordered_map < TransformableCallbackHandle, TransformableCallback >	M_TransformableCallback
typedef boost::signals2::signal< void(void)>	TransformsChangedSignal
typedef std::vector < TimeCacheInterfacePtr >	V_TimeCacheInterface
	The pointers to potential frames that the tree can be made of. The frames will be dynamically allocated at run time when set the first time.
typedef std::vector < TransformableRequest >	V_TransformableRequest
Private Member Functions
std::string	allFramesAsStringNoLock () const
	A way to see what frames have been cached Useful for debugging. Use this call internally.
TimeCacheInterfacePtr	allocateFrame (CompactFrameID cfid, bool is_static)
bool	canTransformInternal (CompactFrameID target_id, CompactFrameID source_id, const ros::Time &time, std::string *error_msg) const
bool	canTransformNoLock (CompactFrameID target_id, CompactFrameID source_id, const ros::Time &time, std::string *error_msg) const
void	createConnectivityErrorString (CompactFrameID source_frame, CompactFrameID target_frame, std::string *out) const
TimeCacheInterfacePtr	getFrame (CompactFrameID c_frame_id) const
	An accessor to get a frame, which will throw an exception if the frame is no there.
int	getLatestCommonTime (CompactFrameID target_frame, CompactFrameID source_frame, ros::Time &time, std::string *error_string) const
	Return the latest rostime which is common across the spanning set zero if fails to cross.
CompactFrameID	lookupFrameNumber (const std::string &frameid_str) const
	String to number for frame lookup with dynamic allocation of new frames.
const std::string &	lookupFrameString (CompactFrameID frame_id_num) const
	Number to string frame lookup may throw LookupException if number invalid.
CompactFrameID	lookupOrInsertFrameNumber (const std::string &frameid_str)
	String to number for frame lookup with dynamic allocation of new frames.
void	testTransformableRequests ()
CompactFrameID	validateFrameId (const char *function_name_arg, const std::string &frame_id) const
template<typename F >
int	walkToTopParent (F &f, ros::Time time, CompactFrameID target_id, CompactFrameID source_id, std::string *error_string) const
template<typename F >
int	walkToTopParent (F &f, ros::Time time, CompactFrameID target_id, CompactFrameID source_id, std::string error_string, std::vector< CompactFrameID > frame_chain) const
	Traverse the transform tree. If frame_chain is not NULL, store the traversed frame tree in vector frame_chain.
bool	warnFrameId (const char *function_name_arg, const std::string &frame_id) const
Private Attributes
TransformsChangedSignal	_transforms_changed_
	Signal which is fired whenever new transform data has arrived, from the thread the data arrived in.
ros::Duration	cache_time_
	How long to cache transform history.
std::map< CompactFrameID, std::string >	frame_authority_
	A map to lookup the most recent authority for a given frame.
boost::mutex	frame_mutex_
	A mutex to protect testing and allocating new frames on the above vector.
M_StringToCompactFrameID	frameIDs_
std::vector< std::string >	frameIDs_reverse
	A map from CompactFrameID frame_id_numbers to string for debugging and output.
V_TimeCacheInterface	frames_
M_TransformableCallback	transformable_callbacks_
uint32_t	transformable_callbacks_counter_
boost::mutex	transformable_callbacks_mutex_
V_TransformableRequest	transformable_requests_
uint64_t	transformable_requests_counter_
boost::mutex	transformable_requests_mutex_
bool	using_dedicated_thread_

Detailed Description

A Class which provides coordinate transforms between any two frames in a system.

This class provides a simple interface to allow recording and lookup of relationships between arbitrary frames of the system.

libTF assumes that there is a tree of coordinate frame transforms which define the relationship between all coordinate frames. For example your typical robot would have a transform from global to real world. And then from base to hand, and from base to head. But Base to Hand really is composed of base to shoulder to elbow to wrist to hand. libTF is designed to take care of all the intermediate steps for you.

Internal Representation libTF will store frames with the parameters necessary for generating the transform into that frame from it's parent and a reference to the parent frame. Frames are designated using an std::string 0 is a frame without a parent (the top of a tree) The positions of frames over time must be pushed in.

All function calls which pass frame ids can potentially throw the exception tf::LookupException

Definition at line 88 of file buffer_core.h.

Member Typedef Documentation

typedef boost::unordered_map<std::string, CompactFrameID> tf2::BufferCore::M_StringToCompactFrameID [private]

A map from string frame ids to CompactFrameID.

Definition at line 327 of file buffer_core.h.

typedef boost::unordered_map<TransformableCallbackHandle, TransformableCallback> tf2::BufferCore::M_TransformableCallback [private]

Definition at line 338 of file buffer_core.h.

typedef boost::function<void(TransformableRequestHandle request_handle, const std::string& target_frame, const std::string& source_frame, ros::Time time, TransformableResult result)> tf2::BufferCore::TransformableCallback

Definition at line 227 of file buffer_core.h.

typedef boost::signals2::signal<void(void)> tf2::BufferCore::TransformsChangedSignal [private]

Definition at line 359 of file buffer_core.h.

typedef std::vector<TimeCacheInterfacePtr> tf2::BufferCore::V_TimeCacheInterface [private]

The pointers to potential frames that the tree can be made of. The frames will be dynamically allocated at run time when set the first time.

Definition at line 320 of file buffer_core.h.

typedef std::vector<TransformableRequest> tf2::BufferCore::V_TransformableRequest [private]

Definition at line 353 of file buffer_core.h.

Constructor & Destructor Documentation

tf2::BufferCore::BufferCore ( ros::Duration cache_time_ = ros::Duration(DEFAULT_CACHE_TIME) )

Constructor

Parameters:

interpolating	Whether to interpolate, if this is false the closest value will be returned
cache_time	How long to keep a history of transforms in nanoseconds

Definition at line 168 of file buffer_core.cpp.

tf2::BufferCore::~BufferCore ( void ) [virtual]

Definition at line 179 of file buffer_core.cpp.

Member Function Documentation

boost::signals2::connection tf2::BufferCore::_addTransformsChangedListener ( boost::function< void(void)> callback )

Add a callback that happens when a new transform has arrived.

Parameters:

callback The callback, of the form void func();

Returns:: A boost::signals2::connection object that can be used to remove this listener

Definition at line 1338 of file buffer_core.cpp.

std::string tf2::BufferCore::_allFramesAsDot ( double current_time ) const

Backwards compatabilityA way to see what frames have been cached Useful for debugging.

Definition at line 1477 of file buffer_core.cpp.

std::string tf2::BufferCore::_allFramesAsDot ( ) const

Definition at line 1561 of file buffer_core.cpp.

void tf2::BufferCore::_chainAsVector	(	const std::string &	target_frame,
		ros::Time	target_time,
		const std::string &	source_frame,
		ros::Time	source_time,
		const std::string &	fixed_frame,
		std::vector< std::string > &	output
	)		const

Backwards compatabilityA way to see what frames are in a chain Useful for debugging.

Definition at line 1566 of file buffer_core.cpp.

bool tf2::BufferCore::_frameExists ( const std::string & frame_id_str ) const

Check if a frame exists in the tree.

Parameters:

frame_id_str The frame id in question

Definition at line 1351 of file buffer_core.cpp.

void tf2::BufferCore::_getFrameStrings ( std::vector< std::string > & ids ) const

A way to get a std::vector of available frame ids.

Definition at line 1375 of file buffer_core.cpp.

int tf2::BufferCore::_getLatestCommonTime	(	CompactFrameID	target_frame,
		CompactFrameID	source_frame,
		ros::Time &	time,
		std::string *	error_string
	)		const `[inline]`

Definition at line 285 of file buffer_core.h.

bool tf2::BufferCore::_getParent	(	const std::string &	frame_id,
		ros::Time	time,
		std::string &	parent
	)		const

Fill the parent of a frame.

Parameters:

frame_id	The frame id of the frame in question
parent	The reference to the string to fill the parent Returns true unless "NO_PARENT"

Definition at line 1357 of file buffer_core.cpp.

CompactFrameID tf2::BufferCore::_lookupFrameNumber ( const std::string & frameid_str ) const [inline]

Definition at line 278 of file buffer_core.h.

CompactFrameID tf2::BufferCore::_lookupOrInsertFrameNumber ( const std::string & frameid_str ) [inline]

Definition at line 281 of file buffer_core.h.

void tf2::BufferCore::_removeTransformsChangedListener ( boost::signals2::connection c )

Definition at line 1344 of file buffer_core.cpp.

CompactFrameID tf2::BufferCore::_validateFrameId	(	const char *	function_name_arg,
		const std::string &	frame_id
	)		const `[inline]`

Definition at line 290 of file buffer_core.h.

TransformableCallbackHandle tf2::BufferCore::addTransformableCallback ( const TransformableCallback & cb )

Internal use only.

Definition at line 1215 of file buffer_core.cpp.

TransformableRequestHandle tf2::BufferCore::addTransformableRequest	(	TransformableCallbackHandle	handle,
		const std::string &	target_frame,
		const std::string &	source_frame,
		ros::Time	time
	)

Internal use only.

Definition at line 1255 of file buffer_core.cpp.

std::string tf2::BufferCore::allFramesAsString ( ) const

A way to see what frames have been cached Useful for debugging.

Definition at line 937 of file buffer_core.cpp.

std::string tf2::BufferCore::allFramesAsStringNoLock ( ) const [private]

A way to see what frames have been cached Useful for debugging. Use this call internally.

regular transforms

Definition at line 943 of file buffer_core.cpp.

std::string tf2::BufferCore::allFramesAsYAML ( double current_time ) const

A way to see what frames have been cached in yaml format Useful for debugging tools.

Definition at line 1153 of file buffer_core.cpp.

std::string tf2::BufferCore::allFramesAsYAML ( ) const

Backwards compatibility for #84

Definition at line 1210 of file buffer_core.cpp.

TimeCacheInterfacePtr tf2::BufferCore::allocateFrame	(	CompactFrameID	cfid,
		bool	is_static
	)		`[private]`

Definition at line 287 of file buffer_core.cpp.

void tf2::BufferCore::cancelTransformableRequest ( TransformableRequestHandle handle )

Internal use only.

Definition at line 1324 of file buffer_core.cpp.

bool tf2::BufferCore::canTransform	(	const std::string &	target_frame,
		const std::string &	source_frame,
		const ros::Time &	time,
		std::string *	error_msg = `NULL`
	)		const

Lookup the twist of the tracking_frame with respect to the observation frame in the reference_frame using the reference point.

Parameters:

tracking_frame	The frame to track
observation_frame	The frame from which to measure the twist
reference_frame	The reference frame in which to express the twist
reference_point	The reference point with which to express the twist
reference_point_frame	The frame_id in which the reference point is expressed
time	The time at which to get the velocity
duration	The period over which to average

Returns:: twist The twist output

This will compute the average velocity on the interval (time - duration/2, time+duration/2). If that is too close to the most recent reading, in which case it will shift the interval up to duration/2 to prevent extrapolation.

Possible exceptions tf2::LookupException, tf2::ConnectivityException, tf2::ExtrapolationException, tf2::InvalidArgumentException

New in geometry 1.1lookup the twist of the tracking frame with respect to the observational frame

This is a simplified version of lookupTwist with it assumed that the reference point is the origin of the tracking frame, and the reference frame is the observation frame.

Possible exceptions tf2::LookupException, tf2::ConnectivityException, tf2::ExtrapolationException, tf2::InvalidArgumentException

New in geometry 1.1Test if a transform is possible

Parameters:

target_frame	The frame into which to transform
source_frame	The frame from which to transform
time	The time at which to transform
error_msg	A pointer to a string which will be filled with why the transform failed, if not NULL

Returns:: True if the transform is possible, false otherwise

Definition at line 788 of file buffer_core.cpp.

bool tf2::BufferCore::canTransform	(	const std::string &	target_frame,
		const ros::Time &	target_time,
		const std::string &	source_frame,
		const ros::Time &	source_time,
		const std::string &	fixed_frame,
		std::string *	error_msg = `NULL`
	)		const

Test if a transform is possible.

Parameters:

target_frame	The frame into which to transform
target_time	The time into which to transform
source_frame	The frame from which to transform
source_time	The time from which to transform
fixed_frame	The frame in which to treat the transform as constant in time
error_msg	A pointer to a string which will be filled with why the transform failed, if not NULL

Returns:: True if the transform is possible, false otherwise

Definition at line 827 of file buffer_core.cpp.

bool tf2::BufferCore::canTransformInternal	(	CompactFrameID	target_id,
		CompactFrameID	source_id,
		const ros::Time &	time,
		std::string *	error_msg
	)		const `[private]`

Definition at line 781 of file buffer_core.cpp.

bool tf2::BufferCore::canTransformNoLock	(	CompactFrameID	target_id,
		CompactFrameID	source_id,
		const ros::Time &	time,
		std::string *	error_msg
	)		const `[private]`

Definition at line 744 of file buffer_core.cpp.

void tf2::BufferCore::clear ( )

Clear all data.

Definition at line 184 of file buffer_core.cpp.

void tf2::BufferCore::createConnectivityErrorString	(	CompactFrameID	source_frame,
		CompactFrameID	target_frame,
		std::string *	out
	)		const `[private]`

Definition at line 926 of file buffer_core.cpp.

ros::Duration tf2::BufferCore::getCacheLength ( ) [inline]

Get the duration over which this transformer will cache.

Definition at line 295 of file buffer_core.h.

tf2::TimeCacheInterfacePtr tf2::BufferCore::getFrame ( CompactFrameID c_frame_id ) const [private]

An accessor to get a frame, which will throw an exception if the frame is no there.

Parameters:

frame_number The frameID of the desired Reference Frame

This is an internal function which will get the pointer to the frame associated with the frame id Possible Exception: tf::LookupException

Definition at line 874 of file buffer_core.cpp.

int tf2::BufferCore::getLatestCommonTime	(	CompactFrameID	target_frame,
		CompactFrameID	source_frame,
		ros::Time &	time,
		std::string *	error_string
	)		const `[private]`

Return the latest rostime which is common across the spanning set zero if fails to cross.

Definition at line 984 of file buffer_core.cpp.

bool tf2::BufferCore::isUsingDedicatedThread ( ) const [inline]

Definition at line 245 of file buffer_core.h.

CompactFrameID tf2::BufferCore::lookupFrameNumber ( const std::string & frameid_str ) const [private]

String to number for frame lookup with dynamic allocation of new frames.

Definition at line 884 of file buffer_core.cpp.

const std::string & tf2::BufferCore::lookupFrameString ( CompactFrameID frame_id_num ) const [private]

Number to string frame lookup may throw LookupException if number invalid.

Definition at line 914 of file buffer_core.cpp.

CompactFrameID tf2::BufferCore::lookupOrInsertFrameNumber ( const std::string & frameid_str ) [private]

String to number for frame lookup with dynamic allocation of new frames.

Definition at line 897 of file buffer_core.cpp.

geometry_msgs::TransformStamped tf2::BufferCore::lookupTransform	(	const std::string &	target_frame,
		const std::string &	source_frame,
		const ros::Time &	time
	)		const

Get the transform between two frames by frame ID.

Parameters:

target_frame	The frame to which data should be transformed
source_frame	The frame where the data originated
time	The time at which the value of the transform is desired. (0 will get the latest)

Returns:: The transform between the frames

Possible exceptions tf2::LookupException, tf2::ConnectivityException, tf2::ExtrapolationException, tf2::InvalidArgumentException

Definition at line 580 of file buffer_core.cpp.

geometry_msgs::TransformStamped tf2::BufferCore::lookupTransform	(	const std::string &	target_frame,
		const ros::Time &	target_time,
		const std::string &	source_frame,
		const ros::Time &	source_time,
		const std::string &	fixed_frame
	)		const

Get the transform between two frames by frame ID assuming fixed frame.

Parameters:

target_frame	The frame to which data should be transformed
target_time	The time to which the data should be transformed. (0 will get the latest)
source_frame	The frame where the data originated
source_time	The time at which the source_frame should be evaluated. (0 will get the latest)
fixed_frame	The frame in which to assume the transform is constant in time.

Returns:: The transform between the frames

Possible exceptions tf2::LookupException, tf2::ConnectivityException, tf2::ExtrapolationException, tf2::InvalidArgumentException

Definition at line 636 of file buffer_core.cpp.

void tf2::BufferCore::removeTransformableCallback ( TransformableCallbackHandle handle )

Internal use only.

Definition at line 1241 of file buffer_core.cpp.

bool tf2::BufferCore::setTransform	(	const geometry_msgs::TransformStamped &	transform,
		const std::string &	authority,
		bool	is_static = `false`
	)

Add transform information to the tf data structure.

Parameters:

transform	The transform to store
authority	The source of the information for this transform
is_static	Record this transform as a static transform. It will be good across all time. (This cannot be changed after the first call.)

Returns:: True unless an error occured

Definition at line 201 of file buffer_core.cpp.

void tf2::BufferCore::setUsingDedicatedThread ( bool value ) [inline]

Definition at line 243 of file buffer_core.h.

void tf2::BufferCore::testTransformableRequests ( ) [private]

Definition at line 1394 of file buffer_core.cpp.

CompactFrameID tf2::BufferCore::validateFrameId	(	const char *	function_name_arg,
		const std::string &	frame_id
	)		const `[private]`

Definition at line 141 of file buffer_core.cpp.

template<typename F >

int tf2::BufferCore::walkToTopParent	(	F &	f,
		ros::Time	time,
		CompactFrameID	target_id,
		CompactFrameID	source_id,
		std::string *	error_string
	)		const `[private]`

Definition at line 309 of file buffer_core.cpp.

template<typename F >

int tf2::BufferCore::walkToTopParent	(	F &	f,
		ros::Time	time,
		CompactFrameID	target_id,
		CompactFrameID	source_id,
		std::string *	error_string,
		std::vector< CompactFrameID > *	frame_chain
	)		const `[private]`