constructor CreateWithComment(AMetafile: TMetafile; ReferenceDevice: HDC; const CreatedBy, Description: String);
Creates an instance of TMetafileCanvas and acquires a handle to a metafile device context with a comment string.
Call CreateWithComment to create an instantiate a TMetafileCanvas object for a metafile that will receive the CreatedBy and Description strings. CreateWithComment sets the size of the TMetafile object from the ReferenceDevice if it does not already have the MMHeight and MMWidth properties set. Create then creates a metafile device context using the CreatedBy and Description strings as a description, and sets the Handle property to its handle. All subsequent drawing methods will draw to the metafile device context.