Function offsetPos

static/editor.md/lib/codemirror/lib/codemirror.js:4126–4131

(pos, old, nw)

  }

  function offsetPos(pos, old, nw) {
    if (pos.line == old.line)
      return Pos(nw.line, pos.ch - old.ch + nw.ch);
    else
      return Pos(nw.line + (pos.line - old.line), pos.ch);
  }

  // Used by replaceSelections to allow moving the selection to the
  // start or around the replaced test. Hint may be "start" or "around".