The Window, App, Context and Entity are most important things in GPUI, it appears everywhere.

• Window - The current window instance, which for handle the Window Level things.
• App - The current application instance, which for handle the Application Level things.
• Context - The Entity Context instance, which for handle the Context Level things.
• Entity - The Entity instance, which for handle the Entity Level things.

For example:

fn new(window: &mut Window, cx: &mut App) {}

impl RenderOnce for MyElement {
    fn render(self, window: &mut Window, cx: &mut App) {}
}

impl Render for MyView {
    fn render(&mut self, window: &mut Window, cx: &mut Context<Self>) {}
}

:::info As you can see, we always use cx to represent App and Context<Self>, which is the standard naming convention for GPUI, we can follow this convention to make our code more readable and maintainable. :::