CS 150 - Prelab 2
Due: Friday 2/24 at the beginning of lab
For the lab on Friday, we will be using the turtle graphics module to
draw a picture. You will have two options, a seascape with fish and
rocks, or a space scene with spaceships and planets (talk to me if
you have an idea of another scene type that uses similar shapes).
The turtle module
An important programming paradigm is code reuse. Rather than writing
your own code, say a turtle module, you can use one that someone has
already written. An important part of coding then is documentation,
both generating it for your programs and being able to understand
other people's documentation.
The documentation for the turtle module can be found at http://docs.python.org/3/library/turtle.html,
and contains an overview of all of the functions available to you.
To get ready for lab on Friday, you're going to need to read a bit
more about some of the functionality of the turtle module. Below are a
few methods that may be useful, but that we haven't focused on in
class. Click on each of them in the documentation and make sure you
understand what they do as well as what parameters they take and what,
if anything, they return.
In addition to looking at the online documentation, also try out the help function,
which takes the name of a function as an argument, and outputs the docstring (i.e.
function description) for us. Start up Spyder and use help to get the documentation for some of the
two functions. Remember you will need to import the turtle module first by typing
from turtle import *
Planning your drawing
Read through this whole section before starting on your drawing. For
fish or spaceships, we will use a triangle function and for rocks or
planets, we will use arbitrarily sized polygons. For example, here is
an example seascape:
On a piece of paper (ideally graph paper) plan out the design for your drawing. The screen size
will be about 700 x 700 (each dimension ranging from -350 to 350).
The origin (0, 0) is in the center of the window, and
the y-axis points UP as usual, so (350, 350) would be the top right corner of the drawing window.
With these dimensions in mind, plan out on the paper where the different shapes
will go, their sizes, etc. In particular:
You should plan on having at least six fish/ships and six rocks/planets (though if you'd like to have
more, that's fine too).
- What is the x, y coordinate of the upper left hand corner your fish/ships?
- What is the side length of each of the fish/ships?
- What is the x, y coordinate of the top of your rocks/planets?
- How many sides and what are the lengths of the sides of your rocks/planets?
Bring this finished plan to class on Friday. I will check the plans at the beginning of class.
Eventually, we'll add bubbles/stars to make it look more interesting, but we'll deal with that on
Friday (though I've included an example below so you'll see what the finished product looks like).