Function compensateForHScroll

external/.scrollLibs.js:4342–4344

(display)

  // but using getBoundingClientRect to get a sub-pixel-accurate
  // result.
  function compensateForHScroll(display) {
    return display.scroller.getBoundingClientRect().left - display.sizer.getBoundingClientRect().left
  }

  // Returns a function that estimates the height of a line, to use as
  // first approximation until the line becomes visible (and is thus