Miscellaneous Operations

• ((get-string-size viewport) string)
  get-string-size takes a viewport descriptor. It returns a function that returns the size of a string as a list of two numbers: the width and height.
• (viewport->snip viewport)
  viewport->snip takes a viewport descriptor. It returns an object that can be inserted into an editor buffer to display the current image in the viewport. (Subsequent drawing to the viewport does not affect the snip's image.)