Instantiating a service with specific initialization values while preserving dependencies can be ...

export class FontSubStyleMemory extends Effect.Service<FontSubStyleMemory>()(
  "FontSubStyleMemory",
  {
    effect: Effect.gen(function* (size: number /* <---- cant do this ???? */) {
      const { toCanvasPx } = yield* CanvasService;
      return yield* Effect.succeed({
        size: toCanvasPx(size)
        /* ... */
      });
    }),
    dependencies: [CanvasService.Live],
  },
) {}

export class FontSubStyleMemory extends Effect.Service<FontSubStyleMemory>()(
  "FontSubStyleMemory",
  {
    effect: Effect.gen(function* (size: number /* <---- cant do this ???? */) {
      const { toCanvasPx } = yield* CanvasService;
      return yield* Effect.succeed({
        size: toCanvasPx(size)
        /* ... */
      });
    }),
    dependencies: [CanvasService.Live],
  },
) {}

export class CanvasService extends Context.Tag("CanvasService")<
  CanvasService,
  {
    toCanvasPx: (value: number) => number;
  }
>() {
  static Live = Layer.service(this);
}

export class CanvasService extends Context.Tag("CanvasService")<
  CanvasService,
  {
    toCanvasPx: (value: number) => number;
  }
>() {
  static Live = Layer.service(this);
}