ColorWall
Project
Program graphical effects for a ColorWall.
Goals
- Have fun experimenting with and creating graphical effects.
- Practice using functions and classes.
- Get experience with graphics programming using the Tkinter GUI toolkit.
- Practice reading other people's code.
Download source code
- Install git if you have not already done so.
- Clone source
git clone [email protected]:jesstess/ColorWall.git
Project steps
1. Learn about HSV values
Run the ColorWall effects again with
python run.py
The names of the effects are printed to the terminal as they are run. Pay particular attention to the first 4 effects:
- SolidColorTest
- HueTest
- SaturationTest
- ValueTest
In all of these effects, a tuple hsv
containing the hue, saturation, and value describing a color are passed to self.wall.set_pixel
to change the color of a single pixel on the wall.
What are the differences between these tests? Given these difference and how they are expressed visually, how does varying hue, saturation, or value change a color?
Check your understanding: what saturation and value would you guess firetruck red have?
Step 1 resources:
- Using tuples: http://www.afterhoursprogramming.com/tutorial/Python/Tuples/
-
Using the
range
function to produce a sequence of numbers: http://docs.python.org/tutorial/controlflow.html#the-range-function -
Using the
time
module to sleep (do nothing for a bit) inside your program: http://docs.python.org/library/time.html
2. Examine Effect
and the interface its subclasses provide
All of the effects inherit from the Effect
class. Examine this class and its __init__
and run
methods.
What is the purpose of the __init__
method?
What is the purpose of the run
method?
Open up run.py
and look at this chunk of code at the bottom of the file:
for effect in effects_to_run: new_effect = effect(wall) print new_effect.__class__.__name__ new_effect.run()
effects.py
exports an Effects
list at the bottom of the file. run.py
goes through every effect in that list, creates a new instance of the effect, and invokes its run
method.
Check your understanding: what would happen if you added an effect to the Effects
list that didn't implement a run
method? (Try it!)
Step 2 resources:
- Creating and using Python functions: http://www.sthurlow.com/python/lesson05/
- Creating and using Python classes: http://www.sthurlow.com/python/lesson08/
-
A discussion on
__init__
andself
: http://stackoverflow.com/questions/625083/python-init-and-self-what-do-they-do
3. Examine the nested for
loop in SolidColorTest
for x in range(self.wall.width): for y in range(self.wall.height): self.wall.set_pixel(x, y, hsv)
This code loops over every pixel in the ColorWall, setting the pixel to a particular hsv
value. After that for
loop is over, self.wall.draw()
updates the display.
Check your understanding: what would happen if you moved the self.wall.draw()
to inside the inner for
loop, just under self.wall.set_pixel(x, y, hsv)
in SaturationTest
? (Try it!)
Tip: you can run individual tests by passing their names as command line arguments (argument -e or --effects) to run.py
. For example, if you only wanted to run SaturationTest
, you could:
python run.py -e SaturationTest
4. Implement a new effect called RainbowTest
It should run for 5 seconds, cycling through the colors in the rainbow, pausing for a moment at each color.
Remember to add your effect to the Effect
list at the bottom of effects.py
!
Test your new effect with
python run.py -e RainbowTest
5. Play with the randomness in Twinkle
Walk through Twinkle
. Find explanations of the random.randint
and random.uniform
functions in the online documentation at http://docs.python.org/library/random.html.
Experiment with these functions at a Python prompt:
import random random.randint(0, 1) random.randint(0, 5) random.uniform(-1, 1)
Then experiment with the numbers that make up the hue and re-run the effect:
python run.py -e Twinkle
Challenge: make Twinkle
twinkle with shades of blue.
6. Implement a new effect that involves randomness!
Remember to add your effect to the Effect
list at the bottom of effects.py
.
Bonus exercises
1. Checkerboard
Find and change the colors used in the Checkerboards
effect, and re-run the effect:
python run.py -e Checkerboards
Then change the line
if (x + y + i) % 2 == 0:
to
if (x + y + i) % 3 == 0:
re-run the effect, and see what changed.
What other patterns can you create by tweaking the math for this effect?
2. Matrix
Find and change the color of the columns in the Matrix
effect, and re-run the effect:
python run.py -e Matrix
Each column that we see on the wall corresponds to a Column
object. Add some randomness to the color used by each column (the variable whose value you changed above) using the random.random
function, re-run the effect, and see what happens.
3. Write more of your own effects!
You have color, time, randomness, letters, and more at your disposal. Go nuts!
Congratulations!
You've read, modified, and added code to a software project that makes art out of pixels. Keep practicing!