layer.shadowX < number>

Defines the shadow direction on the x-axis. A positive value will produce a shadow from the right edge of a layer, whereas a negative value will produce a shadow from the left edge. A visible shadow will only appear if the shadowColor property is also defined.
译：在x轴上的定义阴影方向。 正值会产生阴影的右边缘层，而负值将生产从左边缘的阴影。如果定义的暗调颜色属性也，可见影只会出现。

layerA = new Layer
layerA.shadowX = 10