Shadows
To create a generic shadow, use the shadowColor and shadowBlur properties:
$('canvas').drawArc({ fillStyle: '#58d', shadowColor: '#000', shadowBlur: 10, x: 50, y: 50, radius: 30});Offset Position
The shadow can be offset relative to itself using the shadowX and shadowY properties:
$('canvas').drawArc({ fillStyle: '#58d', strokeStyle: '#8e3', strokeWidth: 4, shadowColor: '#000', shadowBlur: 5, shadowX: -5, shadowY: 5, x: 50, y: 50, radius: 30});