Function paint_document_sheet 

pub fn paint_document_sheet(
    scene: &mut Scene,
    transform: Affine,
    rect: Rect,
    theme: &Theme,
    content: impl FnOnce(&mut Scene),
)

A document set on a reader: a page that brings its own colours (an HTML mail on its light sheet, a web page), drawn by content and clipped to the raised level’s radius, with the hairline derived from the window content it stands on just inside its edge, so a sheet as light as that content still has one.