Functions for creating plots and image files in a unified way regardless of
output format (EPS, PDF, PNG, SVG, TIFF, WMF, etc.). Default device options
as well as scales and aspect ratios are controlled in a uniform way across
all device types. Switching output format requires minimal changes in code.
This package is ideal for large-scale batch processing, because it will
never leave open graphics devices or incomplete image files behind, even on
errors or user interrupts.
