/**
* Represents the viewport of a terminal, the visible area within the larger buffer of output.
* Logic for the virtual scroll bar is included in this object.
+ * @param {Terminal} terminal The Terminal object.
+ * @param {HTMLElement} viewportElement The DOM element acting as the viewport
+ * @param {HTMLElement} charMeasureElement A DOM element used to measure the character size of
+ * the terminal.
*/
function Viewport(terminal, viewportElement, charMeasureElement) {
this.terminal = terminal;