pub fn frame<C: Canvas>(
tool: &mut Tool,
data: &mut Drawing<'_>,
interaction: &Interaction,
painter: &mut Style<'_, C>,
) -> Option<Transition>Expand description
One frame of a tool: preview, then act. The drivers call this and never
ToolTrait::widget directly, which is what makes the order structural —
a tool has no way to reach the preview writers from widget, because the
PreviewPhase they require is minted here and handed only to preview.