rviz_launch.py

# 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.event_handlers import OnProcessExit
from launch.events import Shutdown
from launch.substitutions import LaunchConfiguration
from launch_ros.actions import Node
 
 
def generate_launch_description() -> LaunchDescription:
    # Get the launch directory
    bringup_dir = get_package_share_directory('nav2_bringup')
 
    # Create the launch configuration variables
    namespace = LaunchConfiguration('namespace')
    rviz_config_file = LaunchConfiguration('rviz_config')
    use_sim_time = LaunchConfiguration('use_sim_time')
 
    # 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_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',
    )
 
    declare_use_sim_time_cmd = DeclareLaunchArgument(
        'use_sim_time',
        default_value='false',
        description='Use simulation (Gazebo) clock if true')
 
    # Launch rviz
    start_rviz_cmd = Node(
        package='rviz2',
        executable='rviz2',
        namespace=namespace,
        arguments=['-d', rviz_config_file, '--ros-args', '--log-level', 'warn'],
        output='screen',
        parameters=[{'use_sim_time': use_sim_time}],
        remappings=[
            ('/tf', 'tf'),
            ('/tf_static', 'tf_static'),
        ],
    )
 
    exit_event_handler = RegisterEventHandler(
        event_handler=OnProcessExit(
            target_action=start_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_rviz_config_file_cmd)
    ld.add_action(declare_use_sim_time_cmd)
 
    # Add any conditioned actions
    ld.add_action(start_rviz_cmd)
 
    # Add other nodes and processes we need
    ld.add_action(exit_event_handler)
 
    return ld