Reusable Components

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This step introduces reusable components. The goal is to turn a feature (like a Y‑junction) into a class you can import and place in any device.

What is a custom component?

A custom component is a Python class that inherits from Component. Inside __init__, you build geometry the same way you did in earlier steps—by adding bulk, voids, labels, and ports. The difference is that now your geometry is encapsulated, reusable, and parameterized.

Example — Y‑junction mixer

We’ll build a minimal Y‑junction in small pieces, then provide a full copy‑paste version.

Step 1 — Create a subclass and define geometry in `init`

Your class should:

Subclass Component.
Accept parameters you want to expose (sizes, margins, labels, etc.).
Store init args/kwargs for equality checks (self.init_args, self.init_kwargs).
Call super().__init__() with size, position, and resolution.

Use the same API you already know: add_label, add_void, and add_bulk.

1) Imports + class skeleton

2) Initialize and store parameters

3) Labels + bulk + channel voids

4) Instantiate and preview (before ports)

At this stage, instantiate the component and preview it before adding ports so you can validate the geometry alone.

Y Junction

Ports (what they are and why they matter)

Ports are connection points used by routing and device assembly. A port defines:

Type: IN, OUT, or INOUT
Position: where the port starts
Size: channel size at that port
Normal: the direction the port faces

Even before you learn routing, adding ports makes your component reusable and connectable.

5) Ports

6) Instantiate and preview (after ports)

Now instantiate and preview again after ports are added. This confirms the ports did not affect geometry and the component is ready for routing.