# Objective
Fix https://github.com/bevyengine/bevy/issues/4530
- Make it easier to open/close/modify windows by setting them up as `Entity`s with a `Window` component.
- Make multiple windows very simple to set up. (just add a `Window` component to an entity and it should open)
## Solution
- Move all properties of window descriptor to ~components~ a component.
- Replace `WindowId` with `Entity`.
- ~Use change detection for components to update backend rather than events/commands. (The `CursorMoved`/`WindowResized`/... events are kept for user convenience.~
Check each field individually to see what we need to update, events are still kept for user convenience.
---
## Changelog
- `WindowDescriptor` renamed to `Window`.
- Width/height consolidated into a `WindowResolution` component.
- Requesting maximization/minimization is done on the [`Window::state`] field.
- `WindowId` is now `Entity`.
## Migration Guide
- Replace `WindowDescriptor` with `Window`.
- Change `width` and `height` fields in a `WindowResolution`, either by doing
```rust
WindowResolution::new(width, height) // Explicitly
// or using From<_> for tuples for convenience
(1920., 1080.).into()
```
- Replace any `WindowCommand` code to just modify the `Window`'s fields directly and creating/closing windows is now by spawning/despawning an entity with a `Window` component like so:
```rust
let window = commands.spawn(Window { ... }).id(); // open window
commands.entity(window).despawn(); // close window
```
## Unresolved
- ~How do we tell when a window is minimized by a user?~
~Currently using the `Resize(0, 0)` as an indicator of minimization.~
No longer attempting to tell given how finnicky this was across platforms, now the user can only request that a window be maximized/minimized.
## Future work
- Move `exit_on_close` functionality out from windowing and into app(?)
- https://github.com/bevyengine/bevy/issues/5621
- https://github.com/bevyengine/bevy/issues/7099
- https://github.com/bevyengine/bevy/issues/7098
Co-authored-by: Carter Anderson <mcanders1@gmail.com>
