Move add_volume call to background thread

"""PyVista plotter for CT scans."""

from asyncio import create_task

from asyncio import get_running_loop

from concurrent.futures import ThreadPoolExecutor

from time import time

from typing import Any, Optional

from pyvista import Plotter, themes

from pyvista.trame.ui import get_viewer

from trame.app import asynchronous

from trame_server.core import Server

from trame_server.state import State

        self.vm.render_bind.connect(self.render)

        self.plotter = self.create_plotter()

        self.loading = False

        self.create_ui()

    @property

        view = get_viewer(self.plotter)

        view.ui(mode="server", style="height: 66vh;")

    async def render_in_background(self) -> None:

    def render_in_background(self) -> None:

        start = time()

        self.plotter.add_volume(

            self.vm.get_volume(), clim=self.vm.get_clim(), mapper="gpu", opacity=self.vm.get_opacity()

            self.vm.get_volume(), clim=self.vm.get_clim(), mapper="gpu", opacity=self.vm.get_opacity(), render=False

        )

        self.plotter.view_isometric(self.plotter)

        print(f"PyVista volume rendering: {time() - start:.2f}s", flush=True)

        print(f"Added volume to scene: {time() - start:.2f}s", flush=True)

        self.vm.update_view()

    @asynchronous.task

    async def render(self, _: Optional[Any] = None) -> None:

        loop = get_running_loop()

        with ThreadPoolExecutor() as executor:

            await loop.run_in_executor(executor, self.render_in_background)

    def render(self, _: Optional[Any] = None) -> None:

        self.render_thread = create_task(self.render_in_background())

        start = time()

        self.plotter.render()

        self.plotter.view_isometric()  # type: ignore

        self.vm.update_view()

        print(f"PyVista rendering: {time() - start:.2f}s", flush=True)