EZ Math Movie, Tutorials, Turtle Graphics, penUp and penDown

The turtle draws, or not.

Commands like forward and back move the turtle. By default the turtle draws a line along its path as it moves, but it can also move without drawing. If you want to move the turtle and not have it draw, then you issue the command penUp:


After the command penUp executes, the turtle will not draw as it moves. If you want to later make the turtle draw again, use the command penDown:


The turtle draws only when the pen is down.

penUp and penDown animation

Running the example program

The example program has loop code that runs once. In this loop code the graph is set up, then the turtle is sent home and aimed 'up' at 45 degrees.

Next, the turtle is moved forward in small steps. The pen is alternately switched up and down as these forward steps execute. This creates a dashed line design.

The example program

Angle measurement: Degrees Radians

Go on input

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Next tutorial: setX, setY, and setXY


Here is a link to a related article at EZ Programing Demos:

Pen up and down

All contents of EZ Math Movie are copyrighted: Copyright 2011, Edward A. Zobel. All rights reserved.

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