microscope.cameras.pvcam.PVParam Class Reference

Inheritance diagram for microscope.cameras.pvcam.PVParam:

Public Member Functions
	__init__ (self, camera, param_id)
	set_value (self, new_value)
	access (self)
	available (self)
	count (self)
	values (self)
	current (self)

Static Public Member Functions
	factory (camera, param_id)

Public Attributes
	cam = weakref.proxy(camera)
	param_id = param_id
str	name = _param_to_name[param_id]
	dtype = _dtypemap[self._pvtype]
	available

Protected Member Functions
	_query (self, what=ATTR_CURRENT, force_query=False)

Protected Attributes
int	_pvtype = param_id >> 24 & 255
	_ctype = _typemap[self._pvtype]

Detailed Description

A wrapper around PVCAM parameters.

Definition at line 1199 of file pvcam.py.

Constructor & Destructor Documentation

__init__()

microscope.cameras.pvcam.PVParam.__init__	(		self,
			camera,
			param_id )

Definition at line 1224 of file pvcam.py.

    def __init__(self, camera, param_id):
        # Use a weakref back to the camera to avoid circular dependency.
        self.cam = weakref.proxy(camera)
        self.param_id = param_id
        self.name = _param_to_name[param_id]
        self._pvtype = param_id >> 24 & 255
        if self.name == "PARAM_READOUT_TIME":
            # Bugged. Here is what the SDK says: "The parameter type is
            # incorrectly defined. The actual type is TYPE_UNS32."
            self._pvtype = TYPE_UNS32
        self.dtype = _dtypemap[self._pvtype]
        self._ctype = _typemap[self._pvtype]
        self.__cache = {}
 

Member Function Documentation

_query()

microscope.cameras.pvcam.PVParam._query ( self, what = ATTR_CURRENT, force_query = False )

protected

Query the DLL for an attribute for this parameter.

This returns pythonic types, not ctypes.

Definition at line 1252 of file pvcam.py.

    def _query(self, what=ATTR_CURRENT, force_query=False):
        """Query the DLL for an attribute for this parameter.
 
        This returns pythonic types, not ctypes."""
        err = None
        key = (self, what)  # key for cache
        if self.cam._acquiring and not force_query:
            return self.__cache.get(key, None)
        if what == ATTR_AVAIL:
            return self.available
        elif not self.available:
            raise microscope.DeviceError(
                "Parameter %s is not available" % self.name
            )
        rtype = _attr_map[what]  # return type
        if not rtype:
            rtype = _get_param(self.cam.handle, self.param_id, ATTR_TYPE)
        if rtype.value == TYPE_CHAR_PTR:
            buf_len = _length_map[self.param_id]
            if not buf_len:
                raise microscope.DeviceError(
                    "pvcam: parameter %s not supported in python." % self.name
                )
            try:
                result = _get_param(
                    self.cam.handle, self.param_id, what, buf_len=buf_len
                )
            except Exception as e:
                err = e
            else:
                result = result.value
        else:
            try:
                result = _get_param(self.cam.handle, self.param_id, what)
            except Exception as e:
                err = e
            else:
                result = ctypes.POINTER(self._ctype)(result).contents.value
        # Test on err.args prevents indexing into empty tuple.
        if err and err.args and err.args[0].startswith("pvcam error 49"):
            _logger.warn(
                "Parameter %s not available due to camera state.", self.name
            )
            result = None
        elif err:
            raise e
        else:
            self.__cache[key] = result
        return result
 

access()

microscope.cameras.pvcam.PVParam.access

(

self

)

Return parameter access attribute.

Definition at line 1303 of file pvcam.py.

    def access(self):
        """Return parameter access attribute."""
        return int(
            _get_param(self.cam.handle, self.param_id, ATTR_ACCESS).value
        )
 

available()

microscope.cameras.pvcam.PVParam.available

(

self

)

Return whether or not parameter is available on hardware.

Definition at line 1310 of file pvcam.py.

    def available(self):
        """Return whether or not parameter is available on hardware."""
        return bool(
            _get_param(self.cam.handle, self.param_id, ATTR_AVAIL).value
        )
 

count()

microscope.cameras.pvcam.PVParam.count

(

self

)

Return count of parameter enum entries.

Definition at line 1317 of file pvcam.py.

    def count(self):
        """Return count of parameter enum entries."""
        return int(
            _get_param(self.cam.handle, self.param_id, ATTR_COUNT).value
        )
 

current()

microscope.cameras.pvcam.PVParam.current

(

self

)

Return the current (or cached) parameter value.

Subclasses should override this for more complex data types.

Reimplemented in microscope.cameras.pvcam.PVEnumParam, and microscope.cameras.pvcam.PVStringParam.

Definition at line 1331 of file pvcam.py.

    def current(self):
        """Return the current (or cached) parameter value.
 
        Subclasses should override this for more complex data types."""
        return self._query()
 
 

factory()

microscope.cameras.pvcam.PVParam.factory ( camera, param_id )

static

Create a PVParam or appropriate subclass

Definition at line 1203 of file pvcam.py.

    def factory(camera, param_id):
        """Create a PVParam or appropriate subclass"""
        # A mapping of pv parameters types to python types.
        #   None means unsupported.
        #   Parameters omitted from the mapping will default to PVParam.
        __types__ = {
            TYPE_SMART_STREAM_TYPE: None,
            TYPE_SMART_STREAM_TYPE_PTR: None,
            TYPE_VOID_PTR: None,
            TYPE_VOID_PTR_PTR: None,
            TYPE_ENUM: PVEnumParam,
            TYPE_CHAR_PTR: PVStringParam,
        }
        # Determine the appropiate type from its id.
        pvtype = __types__.get(param_id >> 24 & 255, PVParam)
        if pvtype is None:
            raise microscope.LibraryLoadError(
                "Parameter %s not supported" % _param_to_name[param_id]
            )
        return pvtype(camera, param_id)
 

set_value()

microscope.cameras.pvcam.PVParam.set_value	(		self,
			new_value )

Set a parameter value.

Subclasses should do whatever processing they need on new_value,
then call super().set_value(new_value)

Reimplemented in microscope.cameras.pvcam.PVEnumParam, and microscope.cameras.pvcam.PVStringParam.

Definition at line 1238 of file pvcam.py.

    def set_value(self, new_value):
        """Set a parameter value.
 
        Subclasses should do whatever processing they need on new_value,
        then call super().set_value(new_value)"""
        try:
            ref = ctypes.byref(new_value)
        except TypeError:
            # Need to convert python type to ctype first.
            ref = ctypes.byref(self._ctype(new_value))
        _set_param(self.cam.handle, self.param_id, ref)
        # Read back the value to update cache.
        self._query(force_query=True)
 

values()

microscope.cameras.pvcam.PVParam.values

(

self

)

Get parameter min and max values.

Subclasses for strings and enum override this.

Reimplemented in microscope.cameras.pvcam.PVEnumParam, and microscope.cameras.pvcam.PVStringParam.

Definition at line 1324 of file pvcam.py.

    def values(self):
        """Get parameter min and max values.
 
        Subclasses for strings and enum override this."""
        return (self._query(ATTR_MIN), self._query(ATTR_MAX))
 

Member Data Documentation

_ctype

microscope.cameras.pvcam.PVParam._ctype = _typemap[self._pvtype]

protected

Definition at line 1235 of file pvcam.py.

_pvtype

int microscope.cameras.pvcam.PVParam._pvtype = param_id >> 24 & 255

protected

Definition at line 1229 of file pvcam.py.

available

microscope.cameras.pvcam.PVParam.available

Definition at line 1262 of file pvcam.py.

cam

microscope.cameras.pvcam.PVParam.cam = weakref.proxy(camera)

Definition at line 1226 of file pvcam.py.

dtype

microscope.cameras.pvcam.PVParam.dtype = _dtypemap[self._pvtype]

Definition at line 1234 of file pvcam.py.

name

str microscope.cameras.pvcam.PVParam.name = _param_to_name[param_id]

Definition at line 1228 of file pvcam.py.

param_id

microscope.cameras.pvcam.PVParam.param_id = param_id

Definition at line 1227 of file pvcam.py.

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

• BioImager/PythonMicroscope/microscope/cameras/pvcam.py