We can read in Appendif F: Implementation Requirements> F.6 Notes on implementing an elliptical arc :
If the endpoints (x1, y1) and (x2, y2) are identical, then this is equivalent to completely omitting the elliptical arc segment.
This looks very strange for the following reasons:
- If the empty A-segment is between C and S, then when you discard this segment, the interpretation of S changes.
- This rule is incompatible with other rules: why not omit empty lines or empty curves, but omit empty arcs?
- Browsers (Chrome, Firefox) do not follow this rule. For example, if we drop an empty arc from
M 0 0 C 0 10 10 10 10 0 A 10 10 0 0 0 10 0 S 20 -10 20 0, we get a nonequivalent path M 0 0 C 0 10 10 10 10 0 S 20 -10 20 0.
, : , SVG?