ColorExtract.php

<?php
namespace modules;

use Craft;

// Elements
use craft\elements\Asset;
use craft\elements\Category;

// Events
use spacecatninja\imagerx\services\ImagerService;
use yii\base\Event;
use craft\events\ModelEvent;

// Misc
use craft\events\RegisterTemplateRootsEvent;
use craft\web\View;
use spacecatninja\imagerx\services\ImagerColorService;


class ColorExtract extends \yii\base\Module
{

    public function __construct($id, $parent = null, array $config = [])
    {
        Craft::setAlias('@modules', $this->getBasePath());

        // Base template directory
        Event::on(View::class, View::EVENT_REGISTER_CP_TEMPLATE_ROOTS, function(RegisterTemplateRootsEvent $e) {
            if (is_dir($baseDir = $this->getBasePath() . DIRECTORY_SEPARATOR . 'templates')) {
                $e->roots[$this->id] = $baseDir;
            }
        });

        // Set this as the global instance of this module class
        static::setInstance($this);

        parent::__construct($id, $parent, $config);
    }


    public function init()
    {

        parent::init();

        // Captures an asset being saved.
        Event::on(
            Asset::class,
            Asset::EVENT_AFTER_SAVE,
            function(ModelEvent $event) {

                // Make sure this is a new asset being created
                if ($event->isNew) {

                    // Isolate the asset from the event
                    /** @var Asset $asset */
                    $asset = $event->sender;

                    // Make sure this is an asset that Imager can eat.
                    if ($asset->kind !== 'image' || !in_array(strtolower($asset->getExtension()), ImagerService::getConfig()->safeFileFormats, true)) {
                        return;
                    }

                    // Below are settings for the getColorPalette function in Imager-X

                    // Number of colors (there seems to be a bug, you need to add 1 to the number you want)
                    $colorCount = 9;

                    // The lowest the longest it will take
                    $quality = 10;
                    $colorValue = 'rgb';

                    // Precision used when reducing the possible amount of values
                    // - A value of 1 will result in no reduction, the maximum number of distinct values will be 16,777,216.
                    // - A value of 16 will result in a maximum number of 4,096.
                    $precision = 52;

                    // Fetch the color palette from the image
                    $fullPalette = (new ImagerColorService)->getColorPalette($asset, $colorCount, $quality, $colorValue);

                    // Approximate colors
                    $palette = array_map(static function ($rgb) use ($precision) {
                        return ImagerColorService::rgb2hex(
                            [
                                round($rgb[0] / $precision) * $precision,
                                round($rgb[1] / $precision) * $precision,
                                round($rgb[2] / $precision) * $precision,
                            ]
                        );
                    }, $fullPalette);

                    // Define an array to store the colors we'll want to add to our asset
                    $allColors = [];

                    // Iterate over each colors
                    foreach ($palette as $color) {

                        // Does this color already exist?
                        $exists = Category::find()
                            ->title($color)
                            ->one();

                        if($exists) {
                            // the color already exists, we use its ID
                            $allColors[] = $exists->id;
                        } else {
                            // It's a new color, let's create it
                            $newColor = new Category();
                            $newColor->groupId = 15; // Adjust this to be the correct category id
                            $newColor->title = $color;
                            $newColor->setFieldValue('assetColor', $color);
                            $newColor->setFieldValue('assetColorRgb', implode(",", ImagerColorService::hex2rgb($color)));

                            $newColor = Craft::$app->elements->saveElement($newColor);
                            if (!$newColor) {
                                Craft::error('Couldn’t save the entry "' . $newColor->title . '"', __METHOD__);
                            }

                            $savedColor = Category::find()
                                ->title($color)
                                ->one();

                            $allColors[] = $savedColor->id;
                        }
                    }
                    // Add the colors to the asset colors field
                    $this->_addColorsToAsset($asset->id, $allColors);

                }
            }
        );

    }

    private function _addColorsToAsset($assetId, $allColors) {
        // Fetch our asset
        $asset = Asset::find()
            ->id($assetId)
            ->one();

        // Set the the colors field values
        $asset->setFieldValue('assetColorPalette', $allColors);

        // Save our asset
        if (!Craft::$app->elements->saveElement($asset)) {
            Craft::error('Couldn’t save the colors on the asset "' . $asset->title . '"', __METHOD__);
        }
    }
}