https://github.com/nens/colormaps

Fast and easy discrete and continuous colormaps.
https://github.com/nens/colormaps

Last synced: 4 days ago
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Fast and easy discrete and continuous colormaps.

• Host: GitHub
• URL: https://github.com/nens/colormaps
• Owner: nens
• License: mit
• Created: 2014-04-03T09:35:41.000Z (over 10 years ago)
• Default Branch: master
• Last Pushed: 2022-09-09T08:29:22.000Z (about 2 years ago)
• Last Synced: 2024-04-12T01:12:28.438Z (7 months ago)
• Language: Python
• Size: 216 KB
• Stars: 0
• Watchers: 34
• Forks: 0
• Open Issues: 1
• Metadata Files:
  • Readme: README.rst
  • Changelog: CHANGES.rst
  • License: LICENSE.rst

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README

        
colormaps

=========

Introduction

------------

Transform data into rgba data using discrete lookup tables or color

gradients.

Usage

-----

Create a discrete colormap with the same two colors::

    

    >>> import colormaps

    >>> colormap = colormaps.DiscreteColormap(

    ...     data=[(0, (255, 0, 0, 255)),         

    ...           (1, (0, 0, 255, 127))],

    ...     masked=(255, 0, 0, 255),

    ...     invalid=(0, 255, 0, 255),

    ... )

Create a gradient colormap from red to semi-transparent blue::

    

    >>> import colormaps

    >>> colormap = colormaps.GradientColormap(

    ...     data=[(0, (255, 0,   0, 255)),

    ...           (1, (  0, 0, 255, 127))],

    ...     size=2048,

    ...     masked=(0, 0, 255, 255),

    ... )                                     

Where size is the amount of entries in the prepared look-up table.

Calculate the value at some positions::

    >>> colormap([0, 0.5, 1])

    array([[255,   0,   0, 255],

           [127,   0, 127, 190],

           [  0,   0, 255, 127]], dtype=uint8)

Register the colormap for use in other places::

    >>> colormap.register('my_gradient')

    >>> colormaps.get('my_gradient')

    

Use a collection of predefined colors using a manager::

    

    >>> manager = colormaps.Manager()

    >>> manager.get('jet')

    

    >>> sorted(manager.registered.keys())[:3]

    ['Accent', 'Accent_r', 'Blues']

Or use your own collection::

    >>> manager = colormaps.Manager('path/to/my/colormap/collection')

The path should point to a folder with json-files ('my-colormap.json')

containing the kwargs for colormaps.create() like this::

    {

      "type": "GradientColormap",

      "data": [

          [0.000, [  0,   0,   0, 255]],

          [0.700, [255, 255, 255, 0]],

          [1.000, [255, 255, 255, 255]]

      ]

    }

Development installation

------------------------

For development, you can use a docker-compose setup::

    $ docker-compose build --build-arg uid=`id -u` --build-arg gid=`id -g` lib

    $ docker-compose up --no-start

    $ docker-compose start

    $ docker-compose exec lib bash

Create a virtualenv::

    (docker)$ virtualenv .venv  # note that Dockerfile prepends .venv/bin to $PATH

Install stuff and run the tests::

    (docker)$ pip install -r requirements.txt

    (docker)$ pip install -e .[test]

    (docker)$ pytest

Update packages::

    

    (docker)$ rm -rf .venv

    (docker)$ virtualenv .venv

    (docker)$ pip install -e .

    (docker)$ pip freeze | grep -v colormaps > requirements.txt