>The measurement direction depends on <a href="#verticalType"><code>verticalType</code></a>:

 <ul>
   <li>For <a href="#TYPE_UNSET"><code>TYPE_UNSET</code></a> (i.e. horizontal), this is the vertical position relative to the
       top of the viewport.
   <li>For <a href="#VERTICAL_TYPE_LR"><code>VERTICAL_TYPE_LR</code></a> this is the horizontal position relative to the left of the
       viewport.
   <li>For <a href="#VERTICAL_TYPE_RL"><code>VERTICAL_TYPE_RL</code></a> this is the horizontal position rel