title: How to calculate sizeDelta in RectTransform?
body: <p>I write a custom content fitter that is required for my custom layout. So, I need to control <code>RectTransform.sizeDelta</code> property when anchors aren't same but I can't get that shows this value.<br>
  I don't need <strong>Unity3D API</strong> reference, I read it and got a nothing cuz it says only:  </p>
  
  <blockquote>
    <p>The size of this RectTransform relative to the distances between the
    anchors. If the anchors are together, sizeDelta is the same as size.
    If the anchors are in each of the four corners of the parent, the
    sizeDelta is how much bigger or smaller the rectangle is compared to
    its parent.</p>
  </blockquote>
  
  <p>Can anyone explain in normal language what does it mean? And how can I calculate it manually when anchors aren't same?</p>