fn confine(
    mut confinable_query: Query<(&mut Transform, &Handle<Image>), With<Confinable>>,
    window_query: Query<&Window, With<PrimaryWindow>>,
    assets: Res<Assets<Image>>
) {
    let window = window_query.get_single().unwrap();

    for (mut transform, image_handle) in confinable_query.iter_mut() {
        let image_dimensions = assets.get(image_handle).unwrap().size();

        let half_x = image_dimensions.x / 2.;
        let half_y = image_dimensions.y / 2.;

        let min_x = 0. + half_x;
        let max_x = window.width() - half_x;
        let min_y = 0. + half_y;
        let max_y = window.height() - half_y;

        let mut translation = transform.translation;

        translation.x = translation.x.clamp(min_x, max_x);
        translation.y = translation.y.clamp(min_y, max_y);

        transform.translation = translation;
    }
}