backdrop vs viewport

backdrop

noun
  • An image that serves as a visual background. 

  • A decorated cloth hung at the back of a stage. 

  • The setting or background of an acted performance. 

  • Any background situation. 

verb
  • To serve as a backdrop for. 

viewport

noun
  • A viewing window. 

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

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

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