CNET-142 Turtle Graphics

Introduction to Turtle Graphics

• Part of the default Python graphic package.

• Import the module using import turtle.

Basic Movements

• Move the turtle cursor:

  • Forward: Move forward a specified distance.

  • Turning: Change direction:

    • Left turn by a certain angle.

    • Right turn by a certain angle.

Pen Control

• Pen Up:

  • When the pen is raised, moving the turtle does not draw.

• Pen Down:

  • When the pen is down, moving the turtle leaves a drawing or line.

Drawing Shapes

• Ability to draw geometric shapes:

  • Circles: Create circles of a specified radius.

  • Dots: Draw dots of a specified size.

• Change properties:

  • Change color and size of shapes.

Background and Screen Control

• Change background color and clear the drawing screen.

Coordinate System

• Coordinate origin is at the center (0,0).

• Movement is based on X (horizontal) and Y (vertical) coordinates.

Example Scripts

Simple Movement Example

• Code example that demonstrates moving the turtle and changing pen status.

  • Moving forward with the pen up results in no drawing.

  • Move to specific coordinates and draw shapes with pen down.

Drawing Circles Example

• Drawing multiple circles with varying coordinates and colors.

• Demonstrating the use of pen size and pen color settings.

Using Variables for Dynamic Drawing

• Use variables for coordinates:

  • Example of adjusting X and Y values dynamically to draw multiple shapes.

Additional Features

Text and Labeling

• Ability to write text on the screen using turtle graphics.

  • Can change position based on coordinates.

Animating the Turtle

• Adjust the speed of the turtle's movement:

  • Speed 0 disables animation, allowing for instant movements.

Sophisticated Drawings

Olympic Rings Example

• Step-by-step guide to drawing the Olympic Rings:

  • Set initial coordinates and pen settings for each ring.

  • Draw and fill shapes, then add text.

Compass Example

• Drawing a compass using similar techniques:

  • Position markings for North, South, East, and West.

USA Flag Example

• Drawing the USA flag:

  • Structure to draw various parts of the flag including stripes and stars.

  • Combining all parts into one cohesive picture.

Combining Functions and Graphics

• Example of combining multiple drawings into one script:

  • How to include different functions for drawing.

  • Importance of handling the main loop to prevent the program from freezing.

Conclusion

• Turtle graphics is a powerful tool for creating visualizations in Python.

• Encouragement to explore and modify sample codes for further learning.