text: **EMF Comments Convey Semantic Information**
  
  An EMF is a sequence of drawing commands (GDI and GDI+ commands) that specify 
  
  how to render the visual elements of the document. The EMF does not contain any 
  
  information beyond these commands (for example, "draw an image here," or "draw a 
  
  line over there"). In particular, conventional EMF do not support semantic aspects of the 
  
  document, such as hyperlinks, locale information, and accessibility information. To 
  
  preserve semantic information in the exported document, Publisher injects special 
  
  records in the EMF. These records contain the semantic information. 
  
  The records that represent the semantic information are implemented as special- 
  
  formatted EMF comments. The EMF format allows for comment record types that are 
  
  ignored by the rendering engine for Graphics Device Interface (GDI), but can contain 
  
  arbitrary information. 
  
  As an example, consider a document that contains alternate text. (Alternate text is used 
  
  by document readers to describe images for users with sight impairments.) Publisher 
  
  injects EMF comments before and after rendering the image, and these EMF comments 
  
  specify the alternate text for the image. The add-in interprets the comments and writes 
  
  the information to the fixed-format export file. 