I see example programs that use functions like writetext, and draw lines on the screen using the draw function. I cannot find these functions listed on the Arduino reference page. Where is the reference documentation for those other functions? I'm guessing there are other functions as well.
I think you are looking at Processing
sketches. You might try the documentation on their site.
It appears I was. I didn't understand the difference between programming in Processing Sketches and Arduino Sketches. It appears the Processing environment is designed to graph data obtained from sensors. They support adding a library to communicate with the Arduino.
What I was hoping that there were some functions in the Arduino sketches to allow very simple interfaces with a computer such as reacting to a keypress on the computer keyboard or sending a text message to the host computer.