Mini-Lab: Getting Started with JES
Introduction
The objective of this mini-lab is to become familiar with the
programming environment JES (Jython Environment for Students) which will
be used in COMP107.
Becoming familiar with JES
- Start JES (Start -> All Programs -> JES). It may take a
little while to start.
 
- To start becoming familiar with the JES graphical user interface,
type some simple Python commands into the command area. (This is the
bottom half of the JES window.) Try typing
in the various examples from Exercise 1 in the reading (Programming in
Python and JES).
The first few examples should look
like these simple
commands:
print 3 + 4
print "Hello class"
print "Hello" + "class"
- Look at the Follow-up Analysis questions from Exercise 1 in the
reading. Make sure
you understand these.
- Click on the Help menu, and browse through Sections 2 (Getting
started with JES) and 3 (Programming in Jython).
Working with picture files
Some of the following exercises will have questions to be answered and
turned in at the end of the mini-lab. You may type your answers up in a
Word document, or you may use the sample markdown
file.
- In the JES command area, type the following command (make sure
upper/lower cases are exactly as given here):
myFile = pickAFile()
A file selector will open. Choose a JPEG (.jpg) file from the \My Documents\My Pictures\Sample Pictures
folder. (Or, if you prefer a
wider selection of images, copy several images from the MediaSources
directory to your own M: drive, or a folder on your own hard drive.)
- Type the same command in the program area of JES. Highlight the text
pickAFile
(without the
parenthesis), then click on the Explain pickAfile button on
the bottom of the JES window. What is this function pickAFile()
doing?
Write down your answer in a complete sentence on a new sheet of paper.
- Type the command
print myFile
into the command area.
What is printed? Using sentences, write down the result and explain
what this command is doing.
- Now type in the command
myPict = makePicture(myFile)
.
Again, type the same command in the program area, highlight
makePicture
, then click on the
Explain makePicture button on the bottom of the window. Write down what this function is doing.
- Type the command
print myPict
. What is printed?
Write down your result.
- Type the command
show(myPict)
. A new window should
appear with your picture displayed.
- Go to the JES menu item MediaTools, select Picture
Tool..., and choose the picture
myPict
. After clicking
OK, another window will pop open which shows the picture.
- Experiment with the features provided by the picture tool: change
the zoom level and look at the color values at different points of the
picture by clicking on those points. (Note that color values may not
display correctly unless the picture is zoomed at 100%.) Write down
which image file you used, and the highest and lowest values you find
for red, green, and blue.
Working with sound files
Complete the following exercises if you have time.
- Use the
pickAFile
function to select a sound file from the MediaSources directory:
soundFile = pickAFile()
The sound files have a .wav extension.
- Now type in the command
sound = makeSound(soundFile)
.
- Try playing the sound using the
play
function:
play(sound)
.
If nothing happens, make sure that the volume isn't turned all the way down on your computer.
- Turn in your answers to the questions in these exercises.