rviz_launch.py

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# Copyright (c) 2018 Intel Corporation
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
 
import os
 
from ament_index_python.packages import get_package_share_directory
 
from launch import LaunchDescription
from launch.actions import DeclareLaunchArgument, EmitEvent, RegisterEventHandler
from launch.conditions import IfCondition, UnlessCondition
from launch.event_handlers import OnProcessExit
from launch.events import Shutdown
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node
from nav2_common.launch import ReplaceString
 
 
def generate_launch_description():
    # Get the launch directory
    bringup_dir = get_package_share_directory("nav2_bringup")
 
    # Create the launch configuration variables
    namespace = LaunchConfiguration("namespace")
    use_namespace = LaunchConfiguration("use_namespace")
    rviz_config_file = LaunchConfiguration("rviz_config")
 
    # Declare the launch arguments
    declare_namespace_cmd = DeclareLaunchArgument(
        "namespace",
        default_value="navigation",
        description=(
            "Top-level namespace. The value will be used to replace the "
            "<robot_namespace> keyword on the rviz config file."
        ),
    )
 
    declare_use_namespace_cmd = DeclareLaunchArgument(
        "use_namespace",
        default_value="false",
        description="Whether to apply a namespace to the navigation stack",
    )
 
    declare_rviz_config_file_cmd = DeclareLaunchArgument(
        "rviz_config",
        default_value=os.path.join(bringup_dir, "rviz", "nav2_default_view.rviz"),
        description="Full path to the RVIZ config file to use",
    )
 
    # Launch rviz
    start_rviz_cmd = Node(
        condition=UnlessCondition(use_namespace),
        package="rviz2",
        executable="rviz2",
        name="rviz2",
        arguments=["-d", rviz_config_file],
        output="screen",
    )
 
    namespaced_rviz_config_file = ReplaceString(
        source_file=rviz_config_file, replacements={"<robot_namespace>": ("/", namespace)}
    )
 
    start_namespaced_rviz_cmd = Node(
        condition=IfCondition(use_namespace),
        package="rviz2",
        executable="rviz2",
        name="rviz2",
        namespace=namespace,
        arguments=["-d", namespaced_rviz_config_file],
        output="screen",
        remappings=[
            ("/tf", "tf"),
            ("/tf_static", "tf_static"),
            ("/goal_pose", "goal_pose"),
            ("/clicked_point", "clicked_point"),
            ("/initialpose", "initialpose"),
        ],
    )
 
    exit_event_handler = RegisterEventHandler(
        condition=UnlessCondition(use_namespace),
        event_handler=OnProcessExit(
            target_action=start_rviz_cmd, on_exit=EmitEvent(event=Shutdown(reason="rviz exited"))
        ),
    )
 
    exit_event_handler_namespaced = RegisterEventHandler(
        condition=IfCondition(use_namespace),
        event_handler=OnProcessExit(
            target_action=start_namespaced_rviz_cmd,
            on_exit=EmitEvent(event=Shutdown(reason="rviz exited")),
        ),
    )
 
    # Create the launch description and populate
    ld = LaunchDescription()
 
    # Declare the launch options
    ld.add_action(declare_namespace_cmd)
    ld.add_action(declare_use_namespace_cmd)
    ld.add_action(declare_rviz_config_file_cmd)
 
    # Add any conditioned actions
    ld.add_action(start_rviz_cmd)
    ld.add_action(start_namespaced_rviz_cmd)
 
    # Add other nodes and processes we need
    ld.add_action(exit_event_handler)
    ld.add_action(exit_event_handler_namespaced)
 
    return ld