Function whole_view 

pub fn whole_view(
    scene: &mut Scene,
    transform: Affine,
    rect: Rect,
    openness: f32,
    theme: &Theme,
)

The ground of a whole-view surface that pictures the windows it covers (the workspace overview): the desktop, blurred and tinted as the floating material is, over everything drawn before it, then the modal dim. Unlike modal it hides what it covers once openness reaches 1, because the surface shows those windows itself and they must not be seen twice; on the way there they fade out under it. Opaque base where the theme does not blur (reduced transparency, forced colours) or no desktop is published. Call after everything it covers is drawn.