README

Pick a palette of dominant colors from an image

Requirements

• php 7.1
• ext-imagick

Installation

Clone or download the repository and simply run composer install

Demo

In order to use the demo, run the following command

cd demo
php -S localhost:8000

And open the url localhost:8000 in your browser

Getting started

Use the Lol\ColorPicker\ColorPicker class in your file

Example of usage:

$imageUrl = 'http://some.website/some/image.ext';
$colorPicker = new ColorPicker();
$palette = $colorPicker->pick($imageUrl, ColorPicker::KMEANS, 7, 150);
foreach ($palette as $cluster) {
    echo sprintf("#%02x%02x%02x", ...$cluster['color']) . PHP_EOL; // will print up to 5 hex codes
}

Options

ColorPicker::pick($imageUrl, $algorithm, $paletteSize, $resize);

• $imageUrl is the url of the image you want to pick colors from
• $algorithm is the algorithm to use among ColorPicker::KMEANS, ColorPicker::WEIGHTED_KMEANS, ColorPicker::LOCAL_MAXIMA
• $paletteSize is the maximum quantity of dominant colors you want to pick
• $resize is the width to which the image should be resized, it can be left empty
• $quantization is an array providing the colorspace and number of colors for the quantization, formatted as follow:

$quantization = [
    'colorNumber' => 64,
    'colorSpace' => 1 // RGB space
];

Algorithms

• ColorPicker::KMEANS uses a standard unsupervised Kmeans or Kmeans++ algorithm to calculate k clusters, some clusters can end up empty
• ColorPicker::WEIGHTED_KMEANS implementation of Kmeans from an histogram, calculating the clusters centroids according to coordinate and weight
• ColorPicker::LOCAL_MAXIMA keeps the maximum values among their 27 neighboring cells in a 3d space of quantized rgb values. Incompatible with quantization argument !
• ColorPicker::QUANTIZATION just quantize the colors and return the highest clusters