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ahcorde merged 1 commit into from
Jan 14, 2026
Merged

Add XML/YAML launch file equivalents to Tf2 tutorials (backport #6031) #6161

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68 changes: 56 additions & 12 deletions source/Tutorials/Intermediate/Tf2/Adding-A-Frame-Cpp.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -182,18 +182,48 @@ Finally, add the ``install(TARGETS…)`` section so ``ros2 run`` can find your e
~~~~~~~~~~~~~~~~~~~~~~~~~

Now let's create a launch file for this example.
With your text editor, create a new file called ``turtle_tf2_fixed_frame_demo_launch.py`` in the ``src/learning_tf2_cpp/launch`` directory, and add the following lines:
With your text editor, create a new file called ``turtle_tf2_fixed_frame_demo_launch`` with extension ``.py``, ``.xml``, or ``.yaml`` in the ``src/learning_tf2_cpp/launch`` directory, and add the following lines:

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.py
:language: python
.. tabs::

.. group-tab:: Python

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.py
:language: python

.. group-tab:: XML

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.xml
:language: xml

.. group-tab:: YAML

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.yaml
:language: yaml

This launch file imports the required packages and then creates a ``demo_nodes`` variable that will store nodes that we created in the previous tutorial's launch file.

The last part of the code will add our fixed ``carrot1`` frame to the turtlesim world using our ``fixed_frame_tf2_broadcaster`` node.

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.py
:language: python
:lines: 14-18
.. tabs::

.. group-tab:: Python

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.py
:language: python
:lines: 14-18

.. group-tab:: XML

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.xml
:language: xml
:lines: 3-4

.. group-tab:: YAML

.. literalinclude:: launch/turtle_tf2_fixed_frame_demo_launch.yaml
:language: yaml
:lines: 6-9

1.4 Build
~~~~~~~~~
Expand Down Expand Up @@ -275,7 +305,7 @@ Now you can start the turtle broadcaster demo:

.. code-block:: console

$ ros2 launch learning_tf2_cpp turtle_tf2_fixed_frame_demo_launch.py
$ ros2 launch learning_tf2_cpp turtle_tf2_fixed_frame_demo_launch.xml # .py or .yaml are also acceptable

You should notice that the new ``carrot1`` frame appeared in the transformation tree.

Expand All @@ -290,7 +320,7 @@ One way is to pass the ``target_frame`` argument to the launch file directly fro

.. code-block:: console

$ ros2 launch learning_tf2_cpp turtle_tf2_fixed_frame_demo_launch.py target_frame:=carrot1
$ ros2 launch learning_tf2_cpp turtle_tf2_fixed_frame_demo_launch.xml target_frame:=carrot1 # .py or .yaml are also acceptable

The second way is to update the launch file.
To do so, open the ``turtle_tf2_fixed_frame_demo_launch.py`` file, and add the ``'target_frame': 'carrot1'`` parameter via ``launch_arguments`` argument.
Expand Down Expand Up @@ -442,10 +472,24 @@ Finally, add the ``install(TARGETS…)`` section so ``ros2 run`` can find your e
2.3 Write the launch file
~~~~~~~~~~~~~~~~~~~~~~~~~

To test this code, create a new launch file ``turtle_tf2_dynamic_frame_demo_launch.py`` in the ``src/learning_tf2_cpp/launch`` directory and paste the following code:
To test this code, create a new launch file ``turtle_tf2_dynamic_frame_demo_launch`` with extension ``.py``, ``.xml``, or ``.yaml`` in the ``src/learning_tf2_cpp/launch`` directory and paste the following code:

.. tabs::

.. group-tab:: Python

.. literalinclude:: launch/turtle_tf2_dynamic_frame_demo_launch.py
:language: python

.. group-tab:: XML

.. literalinclude:: launch/turtle_tf2_dynamic_frame_demo_launch.xml
:language: xml

.. group-tab:: YAML

.. literalinclude:: launch/turtle_tf2_dynamic_frame_demo_launch.py
:language: python
.. literalinclude:: launch/turtle_tf2_dynamic_frame_demo_launch.yaml
:language: yaml


2.4 Build
Expand Down Expand Up @@ -528,7 +572,7 @@ Now you can start the dynamic frame demo:

.. code-block:: console

$ ros2 launch learning_tf2_cpp turtle_tf2_dynamic_frame_demo_launch.py
$ ros2 launch learning_tf2_cpp turtle_tf2_dynamic_frame_demo_launch.xml # .py or .yaml are also acceptable

You should see that the second turtle is following the carrot's position that is constantly changing.

Expand Down
70 changes: 57 additions & 13 deletions source/Tutorials/Intermediate/Tf2/Adding-A-Frame-Py.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -159,19 +159,49 @@ Add the following line between the ``'console_scripts':`` brackets:
~~~~~~~~~~~~~~~~~~~~~~~~~

Now let's create a launch file for this example.
With your text editor, create a new file called ``turtle_tf2_fixed_frame_demo_launch.py`` in the ``src/learning_tf2_py/launch`` directory, and add the following lines:
With your text editor, create a new file called ``turtle_tf2_fixed_frame_demo_launch`` with extension ``.py``, ``.xml``, or ``.yaml`` in the ``src/learning_tf2_py/launch`` directory, and add the following lines:

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.py
:name: turtle_tf2_fixed_frame_demo_launch.py
:language: python
.. tabs::

.. group-tab:: Python

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.py
:name: turtle_tf2_fixed_frame_demo_launch.py
:language: python

.. group-tab:: XML

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.xml
:language: xml

.. group-tab:: YAML

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.yaml
:language: yaml

This launch file imports the required packages and then creates a ``demo_nodes`` variable that will store nodes that we created in the previous tutorial's launch file.

The last part of the code will add our fixed ``carrot1`` frame to the turtlesim world using our ``fixed_frame_tf2_broadcaster`` node.

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.py
:language: python
:lines: 14-18
.. tabs::

.. group-tab:: Python

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.py
:language: python
:lines: 14-18

.. group-tab:: XML

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.xml
:language: xml
:lines: 3-4

.. group-tab:: YAML

.. literalinclude:: launch/py_turtle_tf2_fixed_frame_demo_launch.yaml
:language: yaml
:lines: 6-9

1.4 Build
~~~~~~~~~
Expand Down Expand Up @@ -253,7 +283,7 @@ Now you can start the turtle broadcaster demo:

.. code-block:: console

$ ros2 launch learning_tf2_py turtle_tf2_fixed_frame_demo_launch.py
$ ros2 launch learning_tf2_py turtle_tf2_fixed_frame_demo_launch.xml # .py or .yaml are also acceptable

You should notice that the new ``carrot1`` frame appeared in the transformation tree.

Expand All @@ -268,7 +298,7 @@ One way is to pass the ``target_frame`` argument to the launch file directly fro

.. code-block:: console

$ ros2 launch learning_tf2_py turtle_tf2_fixed_frame_demo_launch.py target_frame:=carrot1
$ ros2 launch learning_tf2_py turtle_tf2_fixed_frame_demo_launch.xml target_frame:=carrot1 # .py or .yaml are also acceptable

The second way is to update the launch file.
To do so, open the ``turtle_tf2_fixed_frame_demo_launch.py`` file, and add the ``'target_frame': 'carrot1'`` parameter via ``launch_arguments`` argument.
Expand Down Expand Up @@ -398,10 +428,24 @@ Add the following line between the ``'console_scripts':`` brackets:
2.3 Write the launch file
~~~~~~~~~~~~~~~~~~~~~~~~~

To test this code, create a new launch file ``turtle_tf2_dynamic_frame_demo_launch.py`` in the ``src/learning_tf2_py/launch`` directory and paste the following code:
To test this code, create a new launch file ``turtle_tf2_dynamic_frame_demo_launch`` with extension ``.py``, ``.xml``, or ``.yaml`` in the ``src/learning_tf2_py/launch`` directory and paste the following code:

.. tabs::

.. group-tab:: Python

.. literalinclude:: launch/py_turtle_tf2_dynamic_frame_demo_launch.py
:name: turtle_tf2_dynamic_frame_demo_launch.py

.. group-tab:: XML

.. literalinclude:: launch/py_turtle_tf2_dynamic_frame_demo_launch.xml
:language: xml

.. group-tab:: YAML

.. literalinclude:: launch/py_turtle_tf2_dynamic_frame_demo_launch.py
:name: turtle_tf2_dynamic_frame_demo_launch.py
.. literalinclude:: launch/py_turtle_tf2_dynamic_frame_demo_launch.yaml
:language: yaml


2.4 Build
Expand Down Expand Up @@ -485,7 +529,7 @@ Now you can start the dynamic frame demo:

.. code-block:: console

$ ros2 launch learning_tf2_py turtle_tf2_dynamic_frame_demo_launch.py
$ ros2 launch learning_tf2_py turtle_tf2_dynamic_frame_demo_launch.xml # .py or .yaml are also acceptable

You should see that the second turtle is following the carrot's position that is constantly changing.

Expand Down
96 changes: 83 additions & 13 deletions source/Tutorials/Intermediate/Tf2/Debugging-Tf2-Problems.rst
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Expand Up @@ -70,18 +70,48 @@ to
} catch (const tf2::TransformException & ex) {

And save changes to the file.
In order to run this demo, we need to create a launch file ``start_tf2_debug_demo_launch.py`` in the ``launch`` subdirectory of package ``learning_tf2_cpp``:
In order to run this demo, we need to create a launch file ``start_tf2_debug_demo_launch`` with extension ``.py``, ``.xml``, or ``.yaml`` in the ``launch`` subdirectory of package ``learning_tf2_cpp``:

.. literalinclude:: launch/start_tf2_debug_demo_launch.py
:language: python
.. tabs::

.. group-tab:: Python

.. literalinclude:: launch/start_tf2_debug_demo_launch.py
:language: python

.. group-tab:: XML

.. literalinclude:: launch/start_tf2_debug_demo_launch.xml
:language: xml

.. group-tab:: YAML

.. literalinclude:: launch/start_tf2_debug_demo_launch.yaml
:language: yaml

Don't forget to add the ``turtle_tf2_listener_debug`` executable to the ``CMakeLists.txt`` and build the package.

Now let's run it to see what happens:

.. code-block:: console
.. tabs::

.. group-tab:: XML

.. code-block:: console

$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.py
$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.xml

.. group-tab:: YAML

.. code-block:: console

$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.yaml

.. group-tab:: Python

.. code-block:: console

$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.py

You will now see that the turtlesim came up.
At the same time, if you run the ``turtle_teleop_key`` in another terminal window, you can use the arrow keys to drive the ``turtle1`` around.
Expand Down Expand Up @@ -153,13 +183,37 @@ To fix this bug, just replace ``turtle3`` with ``turtle2`` in line 65.

And now stop the running demo, build it, and run it again:

.. code-block:: console
.. tabs::

.. group-tab:: XML

$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.py
[turtle_tf2_listener_debug-4] [INFO] [1630223704.617382464] [listener_debug]: Could not
transform turtle2 to turtle1: Lookup would require extrapolation into the future. Requested
time 1630223704.617054 but the latest data is at time 1630223704.616726, when looking up
transform from frame [turtle1] to frame [turtle2]
.. code-block:: console

$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.xml
[turtle_tf2_listener_debug-4] [INFO] [1630223704.617382464] [listener_debug]: Could not
transform turtle2 to turtle1: Lookup would require extrapolation into the future. Requested
time 1630223704.617054 but the latest data is at time 1630223704.616726, when looking up
transform from frame [turtle1] to frame [turtle2]

.. group-tab:: YAML

.. code-block:: console

$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.yaml
[turtle_tf2_listener_debug-4] [INFO] [1630223704.617382464] [listener_debug]: Could not
transform turtle2 to turtle1: Lookup would require extrapolation into the future. Requested
time 1630223704.617054 but the latest data is at time 1630223704.616726, when looking up
transform from frame [turtle1] to frame [turtle2]

.. group-tab:: Python

.. code-block:: console

$ ros2 launch learning_tf2_cpp start_tf2_debug_demo_launch.py
[turtle_tf2_listener_debug-4] [INFO] [1630223704.617382464] [listener_debug]: Could not
transform turtle2 to turtle1: Lookup would require extrapolation into the future. Requested
time 1630223704.617054 but the latest data is at time 1630223704.616726, when looking up
transform from frame [turtle1] to frame [turtle2]

And right away we run into the next problem.

Expand Down Expand Up @@ -201,9 +255,25 @@ In the new code we are asking for the transform between the turtles 100 millisec
It is usual to use a longer periods, just to make sure that the transform will arrive.
Stop the demo, build and run:

.. code-block:: console
.. tabs::

.. group-tab:: XML

.. code-block:: console

$ ros2 launch turtle_tf2 start_tf2_debug_demo_launch.xml

.. group-tab:: YAML

.. code-block:: console

$ ros2 launch turtle_tf2 start_tf2_debug_demo_launch.yaml

.. group-tab:: Python

.. code-block:: console

$ ros2 launch turtle_tf2 start_tf2_debug_demo_launch.py
$ ros2 launch turtle_tf2 start_tf2_debug_demo_launch.py

And you should finally see the turtle move!

Expand Down
22 changes: 19 additions & 3 deletions source/Tutorials/Intermediate/Tf2/Learning-About-Tf2-And-Time-Cpp.rst
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Expand Up @@ -70,7 +70,7 @@ Now build the package and try to run the launch file.

.. code-block:: console

$ ros2 launch learning_tf2_cpp turtle_tf2_demo_launch.py
$ ros2 launch learning_tf2_cpp turtle_tf2_demo_launch.xml # .py or .yaml are also acceptable
[INFO] [1629873136.345688064] [listener]: Could not transform turtle2 to turtle1: Lookup would
require extrapolation into the future. Requested time 1629873136.345539 but the latest data
is at time 1629873136.338804, when looking up transform from frame [turtle1] to frame [turtle2]
Expand Down Expand Up @@ -108,9 +108,25 @@ It will block for up to that duration waiting for it to timeout.

You can now build the package and run the launch file.

.. code-block:: console
.. tabs::

.. group-tab:: XML

.. code-block:: console

$ ros2 launch learning_tf2_cpp turtle_tf2_demo_launch.xml

.. group-tab:: YAML

.. code-block:: console

$ ros2 launch learning_tf2_cpp turtle_tf2_demo_launch.yaml

.. group-tab:: Python

.. code-block:: console

$ ros2 launch learning_tf2_cpp turtle_tf2_demo_launch.py
$ ros2 launch learning_tf2_cpp turtle_tf2_demo_launch.py

You should notice that ``lookupTransform()`` will actually block until the transform between the two turtles becomes available (this will usually take a few milliseconds).
Once the timeout has been reached (fifty milliseconds in this case), an exception will be raised only if the transform is still not available.
Expand Down
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