This app lets you draw any 2d shape using a combination of circles with different radii and rotation speeds. For more info see this Video by The Coding Train or this Video by Mathologer.
Requires Python >= 3.6, PyGame 2 and NumPy.
To run the app you can provide a path to a text file containing the points of the desired shape:
python epicycles.py shapes/heart.txt
If you run it without a file path then the app will go into "draw" mode. There you you can draw a shape with the mouse. Then hit enter to watch the circles go.
| Action | Binding |
|---|---|
| Pause/unpause | Space |
| Erase the line | Backspace |
| Toggle line fading | F |
| Toggle visibility of the circles | C |
| Increase speed | + |
| Decrease speed | - |
| Reverse rotation | R |
| Switch between the circles and the drawing mode | Enter |
| Toggle debug mode | F1 |
| Quit | Esc |
- -h, --help: Show a help message and exit.
- -n <int>: Limit the maximum number of circles.
- -s, --scale <float>: A number > 0 and <= 1 indicating how much of the width and height of the window the shape should occupy. To disable scaling set it to 0.
- -f, --fade: Fade the line color over time so that it vanishes after one cycle.
- -r, --reverse: Reverse the rotation direction.
- -p, --paused: Start the app paused.
- -w, --window-size <width> <height>: Specify a custom window width and height in pixels.
- -d, --debug: Start the app in debug mode.