Changes

// Stuff added compared to CanvasRenderingContext2d.

// ---

// back-reference to the printDocument.

readonly attribute PrintDocument printDocument;

// rendering context for preview?

readonly attribute boolean isPreview;

// tell the backend that this page has finished rendering.

void endPage();

// ---

// From here everything stays the same compared to CanvasRenderingContext2d.

// ---

// state

void save(); // push state on state stack