title: Detecting Opacity in Adobe AI and/or EPS files
body: <p>I'm looking to write a very simple program that can read through an EPS and/or AI file and detect if an opacity mask is being used and if possible the number of them in the file.  Digging in to the EPS file specification I'm having trouble pinning down if there's a specific instruction I can search for in the EPS or AI code.</p>
  
  <p>At first I was thinking <code>&lt;xmpTPg:HasVisibleTransparency&gt;True&lt;/xmpTPg:HasVisibleTransparency&gt;</code>
   but this can be set to true even if an opacity mask does not exist.</p>
  
  <p>Can anyone with any familiarity with EPS or AI formats point me in the right direction?</p>
  
  <p><strong>Note</strong>: I am NOT looking to manipulate these files I just want to detect the existence of opacity masks.</p>