Delay Paint objects (gradient/texture, not color) for writing
pattern/shading/function dictionaries to the pdf file when the pageStream is
complete.
TODO: - reuse pattern dictionaries if possible - cyclic function not working
yet (ps calculation)
This class keeps track of all kinds of objects written to a pdf file and
avoids to write them several times instead of referencing the same object
several times.
Call this method in order to inform this class about the transformation
that is necessary to map the pattern's coordinate space to the default
coordinate system of the parent's content stream (in our case the
flipping of the page).