belvedere vs viewport

belvedere

noun
  • A turret or other raised structure offering a pleasant view of the surrounding area. 

  • Bassia scoparia (summer cypress) 

viewport

noun
  • A typically rectangular region representing the range or area currently visible (within a window, screen, etc.). 

  • A viewing window. 

verb
  • To clip (an image or region) so that it fits in a viewport. 

How often have the words belvedere and viewport occurred in a corpus of books? (source: Google Ngram Viewer )