Throughout the GUI layer, the TerminalSize class is used to represent how many rows and columns a given component takes up on screen.
For example, to set the on screen size of a Panel, call the setPreferredSize method and pass in a new TerminalSize:
Panel panel = new Panel();
panel.setPreferredSize(new TerminalSize(40, 2));
You can also pass a TerminalSize object into the constructor of many GUI components, for example, the TextBox component:
// Creates a textbox 40 columns long, 1 row high
TextBox textBox = new TextBox(new TerminalSize(40, 1))