pixelfed/pixelfed

<?php

namespace App\Util\Media;

use App\Util\Blurhash\Blurhash as BlurhashEngine;
use App\Media;

class Blurhash {

    const DEFAULT_HASH = 'U4Rfzst8?bt7ogayj[j[~pfQ9Goe%Mj[WBay';

    public static function generate(Media $media)
    {
        if(!in_array($media->mime, ['image/png', 'image/jpeg', 'video/mp4'])) {
            return self::DEFAULT_HASH;
        }

        if($media->thumbnail_path == null) {
            return self::DEFAULT_HASH;
        }

        $file  = storage_path('app/' . $media->thumbnail_path);

        if(!is_file($file)) {
            return self::DEFAULT_HASH;
        }

        $image = imagecreatefromstring(file_get_contents($file));
        if(!$image) {
            return self::DEFAULT_HASH;
        }
        $width = imagesx($image);
        $height = imagesy($image);

        $pixels = [];
        for ($y = 0; $y < $height; ++$y) {
            $row = [];
            for ($x = 0; $x < $width; ++$x) {
                $index = imagecolorat($image, $x, $y);
                $colors = imagecolorsforindex($image, $index);

                $row[] = [$colors['red'], $colors['green'], $colors['blue']];
            }
            $pixels[] = $row;
        }

        // Free the allocated GdImage object from memory:
        imagedestroy($image);

        $components_x = 4;
        $components_y = 4;
        $blurhash = BlurhashEngine::encode($pixels, $components_x, $components_y);
        if(strlen($blurhash) > 191) {
            return self::DEFAULT_HASH;
        }
        return $blurhash;
    }

}