Chapter 8

graphics

discipline that underlies the representation and display of geometric shapes in two- and three- dimensional space

turtle graphics

toolkit provides a simple and enjoyable way to draw pictures in a window

What is the analogy of turtle graphics?

It’s a turtle crawling on a piece of paper with a pen tied to its tail

Which coordinate system (standard) is used for turtle graphics with the origin (0,0) centered in the window?

Cartesian System

What is another name for the origin (0,0) centered in the window of the turtle’s initial position?

Home

Which four attributes make up a turtle’s state?

Heading, color, width, down

What is an object’s state?

Set of values of its attributes at any given point in time.

What is the initial attribute of a turtle’s heading (direction in which it currently faces).

turtle is initially facing east, or 0 degrees. North is 90 degrees.

What is the initial color attribute of the turtle?

Initially black, the color can be changed to any of more than 16 million other colors.

What is the initial width attribute of the turtle?

The initial width is 1 pixel

What is the initial down attribute of the turtle?

This attribute, which can be either true or false, controls whether the turtle’s pen is up or down. When true (i.e., when the pen is down), the turtle draws a line when it moves. When false (i.e., when the pen is up), the turtle can move without drawing a line.

What is the turtle’s operation in Python called?

A turtle is called an object which is a data value in Python

analog information

contains a continuous range of values

Which information is contained in images, sound, and much of the rest of the physical world?

Analog information

What is a good understanding of analog clock?