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

#include <buffer_core.h>

Inheritance diagram for tf2::BufferCore:

Collaboration diagram for tf2::BufferCore:

Public Types
using	TransformableCallback = std::function< void(TransformableRequestHandle request_handle, const std::string &target_frame, const std::string &source_frame, TimePoint time, TransformableResult result)>

Public Member Functions
	BufferCore (tf2::Duration cache_time_=BUFFER_CORE_DEFAULT_CACHE_TIME)

virtual	~BufferCore (void)

void	clear () override
	Clear all data. More...

bool	setTransform (const geometry_msgs::msg::TransformStamped &transform, const std::string &authority, bool is_static=false)
	Add transform information to the tf data structure. More...

geometry_msgs::msg::TransformStamped	lookupTransform (const std::string &target_frame, const std::string &source_frame, const TimePoint &time) const override
	Get the transform between two frames by frame ID. More...

geometry_msgs::msg::TransformStamped	lookupTransform (const std::string &target_frame, const TimePoint &target_time, const std::string &source_frame, const TimePoint &source_time, const std::string &fixed_frame) const override
	Get the transform between two frames by frame ID assuming fixed frame. More...

bool	canTransform (const std::string &target_frame, const std::string &source_frame, const TimePoint &time, std::string *error_msg=NULL) const override
	Lookup the twist of the tracking_frame with respect to the observation frame in the reference_frame using the reference point. More...

bool	canTransform (const std::string &target_frame, const TimePoint &target_time, const std::string &source_frame, const TimePoint &source_time, const std::string &fixed_frame, std::string *error_msg=NULL) const override
	Test if a transform is possible. More...

std::vector< std::string >	getAllFrameNames () const override
	Get all frames that exist in the system. More...

std::string	allFramesAsYAML (TimePoint current_time) const
	A way to see what frames have been cached in yaml format Useful for debugging tools. More...

std::string	allFramesAsYAML () const

std::string	allFramesAsString () const
	A way to see what frames have been cached Useful for debugging. More...

TransformableCallbackHandle	addTransformableCallback (const TransformableCallback &cb)
	Internal use only. More...

void	removeTransformableCallback (TransformableCallbackHandle handle)
	Internal use only. More...

TransformableRequestHandle	addTransformableRequest (TransformableCallbackHandle handle, const std::string &target_frame, const std::string &source_frame, TimePoint time)
	Internal use only. More...

void	cancelTransformableRequest (TransformableRequestHandle handle)
	Internal use only. More...

void	setUsingDedicatedThread (bool value)

bool	isUsingDedicatedThread () const

bool	_frameExists (const std::string &frame_id_str) const
	Check if a frame exists in the tree. More...

bool	_getParent (const std::string &frame_id, TimePoint time, std::string &parent) const
	Fill the parent of a frame. More...

void	_getFrameStrings (std::vector< std::string > &ids) const
	A way to get a std::vector of available frame ids. More...

CompactFrameID	_lookupFrameNumber (const std::string &frameid_str) const

CompactFrameID	_lookupOrInsertFrameNumber (const std::string &frameid_str)

tf2::TF2Error	_getLatestCommonTime (CompactFrameID target_frame, CompactFrameID source_frame, TimePoint &time, std::string *error_string) const

CompactFrameID	_validateFrameId (const char *function_name_arg, const std::string &frame_id) const

tf2::Duration	getCacheLength ()
	Get the duration over which this transformer will cache. More...

std::string	_allFramesAsDot (TimePoint current_time) const
	Backwards compatabilityA way to see what frames have been cached Useful for debugging. More...

std::string	_allFramesAsDot () const

void	_chainAsVector (const std::string &target_frame, TimePoint target_time, const std::string &source_frame, TimePoint 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. More...

Public Member Functions inherited from tf2::BufferCoreInterface
virtual	~BufferCoreInterface ()=default

Static Public Attributes
static const uint32_t	MAX_GRAPH_DEPTH = 1000UL
	Maximum graph search depth (deeper graphs will be assumed to have loops) More...

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

Member Typedef Documentation

◆ TransformableCallback

using tf2::BufferCore::TransformableCallback = std::function<void(TransformableRequestHandle request_handle, const std::string& target_frame, const std::string& source_frame, TimePoint time, TransformableResult result)>

Constructor & Destructor Documentation

◆ BufferCore()

tf2::BufferCore::BufferCore ( tf2::Duration cache_time_ = BUFFER_CORE_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

◆ ~BufferCore()

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

virtual

Member Function Documentation

◆ clear()

void tf2::BufferCore::clear ( )

overridevirtual

Clear all data.

Implements tf2::BufferCoreInterface.

◆ setTransform()

bool tf2::BufferCore::setTransform	(	const geometry_msgs::msg::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

◆ lookupTransform() [1/2]

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

overridevirtual

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

Implements tf2::BufferCoreInterface.

◆ lookupTransform() [2/2]

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

overridevirtual

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

Implements tf2::BufferCoreInterface.

◆ canTransform() [1/2]

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

overridevirtual

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 1.1

lookup 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 1.1

Test 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

Implements tf2::BufferCoreInterface.

◆ canTransform() [2/2]

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

overridevirtual

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

Implements tf2::BufferCoreInterface.

◆ getAllFrameNames()

std::vector<std::string> tf2::BufferCore::getAllFrameNames ( ) const

overridevirtual

Get all frames that exist in the system.

Implements tf2::BufferCoreInterface.

◆ allFramesAsYAML() [1/2]

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

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

◆ allFramesAsYAML() [2/2]

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

Backwards compatibility for #84

◆ allFramesAsString()

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

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

◆ addTransformableCallback()

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

Internal use only.

◆ removeTransformableCallback()

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

Internal use only.

◆ addTransformableRequest()

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

Internal use only.

◆ cancelTransformableRequest()

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

Internal use only.

◆ setUsingDedicatedThread()

void tf2::BufferCore::setUsingDedicatedThread ( bool value )

inline

◆ isUsingDedicatedThread()

bool tf2::BufferCore::isUsingDedicatedThread ( ) const

inline

◆ _frameExists()

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

◆ _getParent()

bool tf2::BufferCore::_getParent	(	const std::string &	frame_id,
		TimePoint	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"

◆ _getFrameStrings()

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

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

◆ _lookupFrameNumber()

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

inline

◆ _lookupOrInsertFrameNumber()

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

inline

◆ _getLatestCommonTime()

tf2::TF2Error tf2::BufferCore::_getLatestCommonTime	(	CompactFrameID	target_frame,
		CompactFrameID	source_frame,
		TimePoint &	time,
		std::string *	error_string
	)		const

inline

◆ _validateFrameId()

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

inline

◆ getCacheLength()

tf2::Duration tf2::BufferCore::getCacheLength ( )

inline

Get the duration over which this transformer will cache.

◆ _allFramesAsDot() [1/2]

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

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

◆ _allFramesAsDot() [2/2]

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

◆ _chainAsVector()

void tf2::BufferCore::_chainAsVector	(	const std::string &	target_frame,
		TimePoint	target_time,
		const std::string &	source_frame,
		TimePoint	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.

Member Data Documentation

◆ MAX_GRAPH_DEPTH

const uint32_t tf2::BufferCore::MAX_GRAPH_DEPTH = 1000UL

static

Maximum graph search depth (deeper graphs will be assumed to have loops)

The documentation for this class was generated from the following file:

include/tf2/buffer_core.h

Public Types

Public Member Functions

Static Public Attributes

Detailed Description

Member Typedef Documentation

◆ TransformableCallback

Constructor & Destructor Documentation

◆ BufferCore()

◆ ~BufferCore()

Member Function Documentation

◆ clear()

◆ setTransform()

◆ lookupTransform() [1/2]

◆ lookupTransform() [2/2]

◆ canTransform() [1/2]

◆ canTransform() [2/2]

◆ getAllFrameNames()

◆ allFramesAsYAML() [1/2]

◆ allFramesAsYAML() [2/2]

◆ allFramesAsString()

◆ addTransformableCallback()

◆ removeTransformableCallback()

◆ addTransformableRequest()

◆ cancelTransformableRequest()

◆ setUsingDedicatedThread()

◆ isUsingDedicatedThread()

◆ _frameExists()

◆ _getParent()

◆ _getFrameStrings()

◆ _lookupFrameNumber()

◆ _lookupOrInsertFrameNumber()

◆ _getLatestCommonTime()

◆ _validateFrameId()

◆ getCacheLength()

◆ _allFramesAsDot() [1/2]

◆ _allFramesAsDot() [2/2]

◆ _chainAsVector()

Member Data Documentation

◆ MAX_GRAPH_DEPTH