CHAPTER 4
202
Graphics
tent stream may modify user space to be more suitable to its needs by applying
the
coordinate transformation operator,
cm
(see Section 4.3.3, “Graphics State Op-
are not absolute with respect to the current page because they are expressed in a
coordinate system that may slide around and shrink or expand. Coordinate sys-
tem transformation not only enhances device-independence but is a useful tool
in its own right. For example, a content stream originally composed to occupy an
entire page can be incorporated without change as an element of another page by
shrinking the coordinate system in which it is drawn.
Device space for
72-dpi screen
CTM
User space
Device space for
300-dpi printer
FIGURE 4.3
User space