image-diff

CLI tool for comparing images

Installation

Install this tool using pip:

$ pip install image-diff

Image diff

To generate an image showing the difference between two images:

image-diff first.jpg second.jpg -o diff.png

Count differing pixels

To count the number of pixels that have changed, use image-diff count:

image-diff first.jpg second.jpg

This will output a number followed by a newline.

Compile an image

The image-diff compile command exists mainly to make this tool easier to test.

It can be used to compile an image from a JSON definition - for example:

echo '[
    [[0, 0, 0], [0, 0, 0], [0, 0, 0]],
    [[0, 0, 0], [255, 0, 0], [0, 0, 0]],
    [[0, 0, 0], [0, 0, 0], [0, 0, 0]]
]' | image-diff compile - -o one-pixel.png

Similar projects

• pixelmatch by Mapbox is a JavaScript library with an accompanying CLI tool.

Development

To contribute to this tool, first checkout the code. Then create a new virtual environment:

cd image-diff
python -m venv venv
source venv/bin/activate

Or if you are using pipenv:

pipenv shell

Now install the dependencies and test dependencies:

pip install -e '.[test]'

To run the tests:

pytest