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.