kangax/fabric.js — pull request #1314 by rodovich (2014-05-08 00:57:34+00:00)
Title: Use a cubic bezier approximation for rounded rectangle corners.

According to the SVG spec these corners are supposed to be elliptical arcs. HTML canvas does not have methods for elliptical arcs, but a cubic approximation can get within 0.02%.

Using the "magic number" from http://itc.ktu.lt/itc354/Riskus354.pdf.

Fixes #1313.