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Hardware Autofocus Plan

Ways to describe a hardware-based autofocus plan. An autofocus_plan on an MDASequence inserts events with a HardwareAutofocus action into the sequence (for example, every time the stage position changes).

useq.AutoFocusPlan

Bases: FrozenModel

Base class for hardware autofocus plans.

Attributes:

Name Type Description
autofocus_device_name str | None

Optional name of the offset motor device. If None, acquisition engines may attempt to set the offset however they see fit (such as using a current or default autofocus device.)
autofocus_motor_offset float | None

Before autofocus is performed, the autofocus motor should be moved to this offset, if applicable. (Not all autofocus devices have an offset motor.) If None, the autofocus motor should not be moved.
Referenced by: Subclassed by:

as_action 

as_action() -> HardwareAutofocus

Return a useq.HardwareAutofocus for this autofocus plan.

event 

event(event: MDAEvent) -> MDAEvent | None

Return an autofocus useq.MDAEvent if autofocus should be performed.

The z position of the new useq.MDAEvent is also updated if a relative zplan is provided since autofocus should be performed on the home z stack position.

should_autofocus 

should_autofocus(event: MDAEvent) -> bool

Method that must be implemented by a subclass.

Should return True if autofocus should be performed (see useq.AxesBasedAF).

useq.AxesBasedAF

Bases: AutoFocusPlan

Autofocus plan that performs autofocus when any of the specified axes change.

Attributes:

Name Type Description
axes tuple[str, ...]

Tuple of axis label to use for hardware autofocus. At every event in which any axis in this tuple changes, autofocus will be performed. For example, if axes is ('p',) then autofocus will be performed every time the p axis changes (in other words: every time the position is changed).
autofocus_device_name str | None

Optional name of the offset motor device. If None, acquisition engines may attempt to set the offset however they see fit (such as using a current or default autofocus device.)
autofocus_motor_offset float | None

Before autofocus is performed, the autofocus motor should be moved to this offset, if applicable. (Not all autofocus devices have an offset motor.) If None, the autofocus motor should not be moved.
Referenced by: Used by:

should_autofocus 

should_autofocus(event: MDAEvent) -> bool

Return True if autofocus should be performed at this event.

Will return True if any of the axes specified in axes have changed from the previous event.

Source code in src/useq/_hardware_autofocus.py 
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def should_autofocus(self, event: MDAEvent) -> bool:
    """Return `True` if autofocus should be performed at this event.

    Will return `True` if any of the axes specified in `axes` have changed from the
    previous event.
    """
    self._previous, previous = dict(event.index), self._previous
    return any(
        axis in self.axes and previous.get(axis) != index
        for axis, index in event.index.items()
    )