Horizontalization of device ports
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

In the case where the device port needs to be kept horizontal, you can use the ``Horizontalized`` class to achieve the horizontalization of the device port, the specific schematic of this function definition is given in ``gpdk``>``routing``>``horizontalized.py``, please refer to the explanatory notes in the ``horizontalized.py`` script, the core usage of which is as follows.

Horizontalized
^^^^^^^^^^^^^^^^^^^^^^^^^^^^

Full script
-----------------
::

    import math
    from typing import List, Optional, Tuple

    from fnpcell import all as fp
    from gpdk.technology import get_technology
    from gpdk.util import all as util



    class Horizontalized(fp.PCell):
        """
        Attributes:
            device: device whose ports need to be horizontalized
            bend_factory: Optional, bend waveguide factory
            straight_type: Optional, type of final short straight
            straight_length: defaults to 0.1, length of final short straight

        Examples:
        ```python
        TECH = get_technology()
            device = Horizontalized(device=BendCircular(radius=30, waveguide_type=TECH.WG.FWG.C.WIRE, transform=fp.rotate(degrees=30)))
        fp.plot(device)
        ```
        ![Horizontalized](images/horizontalized.png)
        """

        device: fp.IDevice = fp.DeviceParam()
        bend_factory: Optional[fp.IBendWaveguideFactory] = fp.Param(required=False)
        straight_type: Optional[fp.IWaveguideType] = fp.WaveguideTypeParam(required=False)
        straight_length: float = fp.PositiveFloatParam(default=0.1)

        def build(self) -> Tuple[fp.InstanceSet, fp.ElementSet, fp.PortSet]:
            insts, elems, ports = super().build()
            TECH = get_technology()

            bend_factory = self.bend_factory
            straight_type = self.straight_type
            straight_length = self.straight_length

            PI = math.pi
            HALF_PI = PI / 2

            content: List[fp.IDevice] = [self.device]
            for port in self.device.ports:
                if isinstance(port, fp.IOwnedPort) and not port.disabled:
                    port_name = port.name
                    port_orientation = fp.normalize_angle(port.orientation)
                    final_orientation = None
                    if -HALF_PI < port_orientation < HALF_PI:
                        final_orientation = 0
                    elif HALF_PI < port_orientation < PI or -PI < port_orientation < -HALF_PI:
                        final_orientation = PI

                    if final_orientation is not None:
                        turning_angle = fp.normalize_angle(final_orientation - port_orientation)
                        if fp.is_nonzero(turning_angle):
                            port = util.links.bend(TECH, content, start=port, radians=turning_angle, bend_factory=bend_factory)
                            if straight_length is not None:
                                port = util.links.straight(TECH, content, start=port, length=straight_length, end_type=straight_type)
                            port = port.with_name(port_name)

                ports += port

            insts += content
            return insts, elems, ports


    if __name__ == "__main__":
        from gpdk.util.path import local_output_file

        gds_file = local_output_file(__file__).with_suffix(".gds")
        library = fp.Library()

        TECH = get_technology()
        # =============================================================
        # fmt: off

        from gpdk.components.bend.bend_circular import BendCircular
        from gpdk.technology.waveguide_factory import EulerBendFactory

        library += Horizontalized(device=BendCircular(radius=30, waveguide_type=TECH.WG.FWG.C.WIRE, transform=fp.rotate(degrees=30)))
        library += Horizontalized(device=BendCircular(radius=30, waveguide_type=TECH.WG.FWG.C.WIRE, transform=fp.rotate(degrees=30)), bend_factory=EulerBendFactory(radius_min=25, l_max=25, waveguide_type=TECH.WG.FWG.C.WIRE))

        # fmt: on
        # =============================================================
        fp.export_gds(library, file=gds_file)
        # fp.plot(library)


Section Script Definition
-------------------------------------

Create horizontalized components ports and export layouts
============================================================
::

    if __name__ == "__main__":
        from gpdk.util.path import local_output_file

        gds_file = local_output_file(__file__).with_suffix(".gds")
        library = fp.Library()

        TECH = get_technology()
        # =============================================================
        # fmt: off

        from gpdk.components.bend.bend_circular import BendCircular
        from gpdk.technology.waveguide_factory import EulerBendFactory

        library += Horizontalized(device=BendCircular(radius=30, waveguide_type=TECH.WG.FWG.C.WIRE, transform=fp.rotate(degrees=30)))
        library += Horizontalized(device=BendCircular(radius=30, waveguide_type=TECH.WG.FWG.C.WIRE, transform=fp.rotate(degrees=30)), bend_factory=EulerBendFactory(radius_min=25, l_max=25, waveguide_type=TECH.WG.FWG.C.WIRE))

        # fmt: on
        # =============================================================
        fp.export_gds(library, file=gds_file)
        # fp.plot(library)

Here, we use the ``Horizontalized`` class to horizontalize the port during the transition, where the device parameter input is used to receive the device that needs to be horizontalized, it is the device that will be horizontalized by the port.

``straight_type`` receives the type of straight waveguide used in the horizontalization process. ``straight_length`` receives the length of the straight waveguide after horizontalization, and ``bend_factory`` receives the curve type of the waveguide. In the following figure, we can see the device after port horizontalization.

GDS Layout
------------------------

.. image:: ../images/horizontalized1.png