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.
