page.originY < number>

Defines how pages will be vertically snapped to. The origin is defined as a number between 0 and 1, where 0 is the top-edge and 1 the bottom-edge. The default value is 0.5, the center.
译：定义页面如何将垂直对齐到。起源是定义为介于0和1，其中0是顶边和1的底部边缘。默认值为0.5，该中心。

page = new PageComponent
page.originY = 0