render() called too often with multiple widgets about textual HOT 5 CLOSED

def on_mount(self):
    self.width_height = None
    # self.collect_data_and_construct_panel() fails because self.width_height is not available yet
    self.panel = "empty"
    self.set_interval(5.0, self.collect_data_and_construct_panel)

def render(self):
    return self.panel

async def on_resize(self, event):
    self.width_height = (event.width, event.height)

def collect_data_and_construct_panel(self):
    # use self.width, self.height
    self.panel = "fancy panel"[:self.width]

def on_mount(self):
    self.is_first_render = True
    self.set_interval(5.0, self.collect_data_and_construct_panel)

def render(self):
    if self.is_first_render:
        self.collect_data_and_construct_panel()  # self.width_heigh available
        self.is_first_render = False
    return self.panel

# ...

from textual.app import App
from textual.widget import Widget

from rich import box


class RenderCounter(Widget):
    def on_mount(self):
        self.k = [0]
        self.set_interval(2.0, self.refresh)

    def render(self):
        self.k.append(self.k[-1] + 1)
        return " ".join([str(item) for item in self.k])


class CounterApp(App):
    CSS = """.box {
        height: 1fr;
        border: solid green;
    }
    """
    def compose(self):
        yield RenderCounter(classes="box")
        yield RenderCounter(classes="box")
        yield RenderCounter(classes="box")
        yield RenderCounter(classes="box")
        yield RenderCounter(classes="box")


CounterApp().run()