PGS user's manual for PGS Version 2. 0
S.A. Brown, D. Braddy · OSTI OAI (U.S. Department of Energy Office of Scientific and Technical Information) · 1993
One of the biggest headaches for portability is graphics. The objective evidence is that the field is immature. One cannot exactly say that there are no graphics standards. The real problem is that there are too many standards. PGS is an application program interface (API) that is independent of the underlying host graphics system. All of the graphics portability headaches are confined to PGS and applications which use PGS are completely portable. PGS currently sits on top of X Windows on UNIX platforms, Quickdraw on Macintoshes, and Microsoft's graphics library on DOS platforms. PGS takes a least common denominator approach regarding what graphics functionality it supports. The goal is to run on the widest variety of machines. This model will almost certainly change in time as both graphics hardware and software evolve and become ubiquitous across platforms. PGS structures display surfaces with a viewport defined in normalized coordinates, an enclosing boundary where axes are drawn which is defined as a set of offsets from the viewport window, and a world coordinate system attached to the viewport. The enclosing boundary is useful for obtaining a standoff between rendered data such as line plots and the axes used to measure the rendering.more » PGS supports both line and text drawing primitives, line and text attributes, and bit maps for handling images and other cell array data. Most functionality in PGS is either primitive operations such as moves and draws or at a very high level such as axis drawing and the rendering algorithms that it supports. These rendering algorithms have two interfaces: one for [open quotes]raw[close quotes] data; and one for PML type mappings. This gives a great deal of flexibility to the application developer. PGS has the following rendering algorithms currently: 1D line plots; 2D contour plots; 2D vector plots; 2D image plots; 3D wire frame mesh plots (for 2D data sets); and Grotrian diagram plots.« less