https://github.com/nschloe/epicycler

Create epicycle animations.
https://github.com/nschloe/epicycler

astronomy fourier fourier-transform mathematics python

Last synced: about 1 month ago
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Create epicycle animations.

• Host: GitHub
• URL: https://github.com/nschloe/epicycler
• Owner: nschloe
• Created: 2018-07-08T20:47:56.000Z (over 6 years ago)
• Default Branch: master
• Last Pushed: 2018-07-09T17:15:01.000Z (over 6 years ago)
• Last Synced: 2024-11-02T00:42:12.370Z (about 2 months ago)
• Topics: astronomy, fourier, fourier-transform, mathematics, python
• Language: Python
• Homepage:
• Size: 4.12 MB
• Stars: 15
• Watchers: 4
• Forks: 2
• Open Issues: 0
• Metadata Files:
  • Readme: README.md

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README

        
# epicycler

[![CircleCI](https://img.shields.io/circleci/project/github/nschloe/epicycler/master.svg)](https://circleci.com/gh/nschloe/epicycler/tree/master)

[![codecov](https://img.shields.io/codecov/c/github/nschloe/epicycler.svg)](https://codecov.io/gh/nschloe/epicycler)

[![Code style: black](https://img.shields.io/badge/code%20style-black-000000.svg)](https://github.com/ambv/black)

[![PyPi Version](https://img.shields.io/pypi/v/epicycler.svg)](https://pypi.org/project/epicycler)

[![GitHub stars](https://img.shields.io/github/stars/nschloe/epicycler.svg?logo=github&label=Stars)](https://github.com/nschloe/epicycler)

![circles](https://nschloe.github.io/epicycler/circles.gif)

[Epicylces](https://en.wikipedia.org/wiki/Deferent_and_epicycle) have been used for

millenia to describe the motion of planets; even

[Copernicus](https://en.wikipedia.org/wiki/Nicolaus_Copernicus) still used them. They

got out of fashion when [Kepler](https://en.wikipedia.org/wiki/Johannes_Kepler)

thought about ellipses, but one can still fool around with epicycles a bit. See

[mathologer's awesome video about it](https://youtu.be/qS4H6PEcCCA) (which in fact

motivated this little package).

### Installation

epicycler is [available from the Python Package

Index](https://pypi.org/project/epicycler/), so simply type

```

pip install -U epicycler

```

to install or upgrade.

### Create animations from polygons

Given a number of 2D polygonal points, epicycler creates nice animations. For example,

the above is created with

```bash

epicycler-poly \

  0.0 0.0 \

  1.0 0.0 \

  1.0 2.0 \

  -0.5 1.1 \

  -0.5 2.1 \

  --xylim -1.5 +2.0 -1.3 3.0

```

See

```bash

epicycler-poly -h

```

for more options.

### Create animations from image files

![seagull](https://nschloe.github.io/epicycler/seagull.png)

Given a (small) linedrawing image file like the above seagull,

epicycler can create an animation from it

```bash

epicycler-image in.png -c 0.5

```

Use the `-c` option for reducing the number of circles by cutting off those smaller than

the given threshold radius; notice then how the polygon points are not followed exactly:

![seagull-gif](https://nschloe.github.io/epicycler/seagull.gif)

### Creating a GIF

```bash

ffmpeg -i out.mp4 -r 10 'frame-%03d.png'

convert -delay 5 -loop 0 frame-*.png out.gif

```

### Testing

To run the epicycler unit tests, check out this repository and type

```

pytest

```

### Distribution

To create a new release

1. bump the `__version__` number,

2. publish to PyPi and GitHub:

    ```

    make publish

    ```

### License

epicycler is published under the [MIT license](https://en.wikipedia.org/wiki/MIT_License).