has-transformed-position (#17)

Co-authored-by: pre-commit-ci[bot] <66853113+pre-commit-ci[bot]@users.noreply.github.com>

Author: ddkohler

yaqd-core/yaqd_core/_has_transformed_position.py

@@ -0,0 +1,93 @@
+__all__ = ["HasTransformedPosition"]
+
+
+import pathlib
+from typing import Dict, Any, Optional, List
+
+from yaqd_core import HasLimits, HasPosition, IsDaemon
+
+
+class HasTransformedPosition(HasLimits, HasPosition, IsDaemon):
+    def __init__(
+        self, name: str, config: Dict[str, Any], config_filepath: pathlib.Path
+    ):
+        super().__init__(name, config, config_filepath)
+        self._native_units = None
+
+    # --- conversion of coordinates ---------------------------------------------------------------
+
+    def to_native(self, transformed_position):
+        relative = self._transformed_to_relative(transformed_position)
+        return relative + self._state["native_reference_position"]
+
+    def to_transformed(self, native_position):
+        relative = native_position - self._state["native_reference_position"]
+        return self._relative_to_transformed(self, relative)
+
+    def _relative_to_transformed(self, relative_position):
+        """convert a relative coordinate to a transformed coordinate.
+        Relative coordinates differ from natural coordinates in that the null position has been subtracted.
+        (i.e. in relative coordinates reference position is zero).
+
+        This placeholder function has trivial behavior, f(x) = x.
+        Daemons that need more than a reference_position should overload this method.
+        Note that overloads should still obey inversion:
+        ```
+        _relative_to_transformed(_transformed_to_relative(x)) == x
+        ```.
+        """
+        return relative_position
+
+    def _transformed_to_relative(self, transformed_position):
+        """convert a transformed coordinate to a relative coordinate
+        Relative coordinates differ from natural coordinates in that the null position has been subtracted.
+        (i.e. in relative coordinates reference position is zero).
+
+        This placeholder function has trivial behavior, f(x) = x.
+        Daemons that need more than a reference_position should overload this method.
+        Note that overloads should still obey inversion:
+        ```
+        _relative_to_transformed(_transformed_to_relative(x)) == x
+        ```.
+        """
+        return transformed_position
+
+    # --- methods for transformed positions -------------------------------------------------------
+
+    def set_position(self, position: float) -> None:
+        super().set_position(self.to_native(position))
+
+    def get_position(self) -> float:
+        return self.to_transformed(self._state["position"])
+
+    def get_destination(self) -> float:
+        return self.to_transformed(self._state["destination"])
+
+    def in_limits(self, position: float) -> bool:
+        return super().in_limits(self.to_native(position))
+
+    def get_limits(self) -> List[float]:
+        return [self.to_transformed(lim) for lim in super().get_limits()]
+
+    # --- native properties -----------------------------------------------------------------------
+
+    def get_native_reference(self) -> float:
+        return self._state["native_reference_position"]
+
+    def set_native_reference(self, native_position):
+        self._state["native_reference_position"] = native_position
+
+    def set_native_position(self, native_position):
+        super().set_position(native_position)
+
+    def get_native_position(self) -> float:
+        return self._state["position"]
+
+    def get_native_destination(self) -> float:
+        return self._state["destination"]
+
+    def get_native_limits(self) -> List[float]:
+        return super().get_limits()
+
+    def get_native_units(self) -> Optional[str]:
+        return self._native_units