This is complicated by two differences with PostScript.
- The coordinate space of SVG is origin top-left, for PostScript it is origin bottom-left.
- Clipping in PostScript works by changing the graphics state
Clip a path, then all subsequent drawing be rendered only
when it is within the clip bounds. Clearly using clipping
paths within a
gsave ... grestoreblock is a good idea...
SVG uses tagging. A clipPath element is declared and named
then referenced in subsequent elements via the clip-path