Shadows 阴影

To create a generic shadow, use the shadowColor and shadowBlur properties:
要创建一个通用的阴影，要使用shadowColor和shadowBlur属性

$('canvas').drawArc({
  fillStyle: '#58d',
  shadowColor: '#000',
  shadowBlur: 10,
  x: 50, y: 50,
  radius: 30
});

Offset Position 偏移位置

The shadow can be offset relative to itself using the shadowX and shadowY properties:
阴影可以使用shadowX和shadowY属性来相对于它本身偏移。

$('canvas').drawArc({
  fillStyle: '#58d',
  strokeStyle: '#8e3',
  strokeWidth: 4,
  shadowColor: '#000',
  shadowBlur: 5,
  shadowX: -5, shadowY: 5,
  x: 50, y: 50,
  radius: 30
});