def __init__(self):
super().__init__('slide_show')
self._bridge = cv_bridge.CvBridge()
dir_desc = ParameterDescriptor()
# TODO(sloretz) Allow changing directory
dir_desc.read_only = True
dir_desc.description = 'Directory from which images will be published'
dir_desc.type = ParameterType.PARAMETER_STRING
dir_desc.name = 'directory'
self.declare_parameter(dir_desc.name, os.path.abspath(os.curdir),
dir_desc)
self._dirpath = self.get_parameter(dir_desc.name).value
self._current_file = None
image_qos = QoSProfile(history=QoSHistoryPolicy.KEEP_LAST,
durability=QoSDurabilityPolicy.TRANSIENT_LOCAL,
reliability=QoSReliabilityPolicy.RELIABLE,
depth=1)
self._image_pub = self.create_publisher(Image, 'images', image_qos)
period_desc = ParameterDescriptor()
# TODO(sloretz) allow changing period
period_desc.read_only = True
period_desc.description = 'Time between publishing images (seconds)'
period_desc.type = ParameterType.PARAMETER_DOUBLE
period_desc.name = 'period'
self.declare_parameter(period_desc.name, 5.0, period_desc)
period = self.get_parameter(period_desc.name).value
self._next_slide_timer = self.create_timer(period, self.on_timer)
self.publish_next()
def _declare_qos_parameters(entity_type: Union[Type[Publisher],
Type[Subscription]],
node: 'Node', topic_name: Text, qos: QoSProfile,
options: QoSOverridingOptions) -> QoSProfile:
"""
Declare QoS parameters for a Publisher or a Subscription.
:param entity_type: Either `rclpy.node.Publisher` or `rclpy.node.Subscription`.
:param node: Node used to declare the parameters.
:param topic_name: Topic name of the entity being created.
:param qos: Default QoS settings of the entity being created, that will be overridden
with the user provided QoS parameter overrides.
:param options: Options that indicates which parameters are going to be declared.
"""
if not issubclass(entity_type, (Publisher, Subscription)):
raise TypeError(
'Argument `entity_type` should be a subclass of Publisher or Subscription'
)
entity_type_str = 'publisher' if issubclass(entity_type,
Publisher) else 'subscription'
id_suffix = '' if options.entity_id is None else f'_{options.entity_id}'
name = f'qos_overrides.{topic_name}.{entity_type_str}{id_suffix}.' '{}'
description = '{}' f' for {entity_type_str} `{topic_name}` with id `{options.entity_id}`'
allowed_policies = _get_allowed_policies(entity_type)
for policy in options.policy_kinds:
if policy not in allowed_policies:
continue
policy_name = policy.name.lower()
descriptor = ParameterDescriptor()
descriptor.description = description.format(policy_name)
descriptor.read_only = True
try:
param = node.declare_parameter(
name.format(policy_name),
_get_qos_policy_parameter(qos, policy), descriptor)
except ParameterAlreadyDeclaredException:
param = node.get_parameter(name.format(policy_name))
_override_qos_policy_with_param(qos, policy, param)
if options.callback is not None:
result = options.callback(qos)
if not result.successful:
raise InvalidQosOverridesError(
f"{description.format('Provided QoS overrides')}, are not valid: {result.reason}"
)
