prepare

Settles whatever the process needs before a preview is composed in it.

Called once, before anything Swing is touched, on the thread the process started on, so a system property that only takes effect before the toolkit initializes - sun.java2d.uiScale among them - can still be set here.

A Preview that states a look and feel of its own installs it after this returns, so an annotation overrides what this settles rather than the other way round.

A throw from here fails every preview on the classpath, and is reported in place of each rendering.