anchor.diff:      PAGE_FIT,
       PAGE_WIDTH,
       _0_50,          // <2>
  +    _0_75,
       ...
       _4_00;          // <3>
   }
  
positive.code: [source,java]
  ----
  @PdfJsViewer(
      initialPageNum = 1,             // <1>
      initialScale = Scale._1_00,     // <2>
      initialHeight = 600             // <3>
  )
  public Blob getBlob() {
      return getSelected() != null ? getSelected().getBlob() : null;
  }
  ----
  <1> initial page to render, defaults to first page
  <2> scaling, defaults to 100%
  <3> height of the panel, in pixels
  
  
  The `Scale` enum corresponds to the scale drop-down in the view, and is defined as:
  
negative.code: To fit their particular screen, they may want to adjust the zoom level and/or height of the panel.
  It would however be very tiresome of the next document viewed reset to the defaults specified in the `@PdfJsViewer`.
  
  Related, support a user views a first document and navigate to some other page.
  She then moves on to second document, and then goes back to the first document once more.
  It would again be annoying if she had start back at page 1 and navigate once more to the page they were previously at.
  
  To support these two use cases the component therefore provides an optional SPI service.
  Implementations of this SPI service can provide hints (`Advice`) which override the defaults of the `@PdfJsViewer` annotation.
  
  The SPI is defined as:
  