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| 1 | +<?php |
| 2 | + |
| 3 | +declare(strict_types=1); |
| 4 | +/** |
| 5 | + * @copyright 2024 Maxence Lange <[email protected]> |
| 6 | + * |
| 7 | + * @author Maxence Lange <[email protected]> |
| 8 | + * |
| 9 | + * @license GNU AGPL version 3 or any later version |
| 10 | + * |
| 11 | + * This program is free software: you can redistribute it and/or modify |
| 12 | + * it under the terms of the GNU Affero General Public License as |
| 13 | + * published by the Free Software Foundation, either version 3 of the |
| 14 | + * License, or (at your option) any later version. |
| 15 | + * |
| 16 | + * This program is distributed in the hope that it will be useful, |
| 17 | + * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| 18 | + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
| 19 | + * GNU Affero General Public License for more details. |
| 20 | + * |
| 21 | + * You should have received a copy of the GNU Affero General Public License |
| 22 | + * along with this program. If not, see <http://www.gnu.org/licenses/>. |
| 23 | + * |
| 24 | + */ |
| 25 | + |
| 26 | +namespace OC\Blurhash\Listener; |
| 27 | + |
| 28 | +use GdImage; |
| 29 | +use kornrunner\Blurhash\Blurhash; |
| 30 | +use OC\Files\Node\File; |
| 31 | +use OCP\EventDispatcher\Event; |
| 32 | +use OCP\EventDispatcher\IEventDispatcher; |
| 33 | +use OCP\EventDispatcher\IEventListener; |
| 34 | +use OCP\Files\GenericFileException; |
| 35 | +use OCP\Files\NotFoundException; |
| 36 | +use OCP\Files\NotPermittedException; |
| 37 | +use OCP\FilesMetadata\AMetadataEvent; |
| 38 | +use OCP\FilesMetadata\Event\MetadataBackgroundEvent; |
| 39 | +use OCP\FilesMetadata\Event\MetadataLiveEvent; |
| 40 | +use OCP\IPreview; |
| 41 | +use OCP\Lock\LockedException; |
| 42 | + |
| 43 | +/** |
| 44 | + * Generate a Blurhash string as metadata when image file is uploaded/edited. |
| 45 | + * |
| 46 | + * @template-implements IEventListener<AMetadataEvent> |
| 47 | + */ |
| 48 | +class GenerateBlurhashMetadata implements IEventListener { |
| 49 | + private const RESIZE_BOXSIZE = 300; |
| 50 | + |
| 51 | + private const COMPONENTS_X = 4; |
| 52 | + private const COMPONENTS_Y = 3; |
| 53 | + |
| 54 | + public function __construct( |
| 55 | + private IPreview $preview, |
| 56 | + ) { |
| 57 | + } |
| 58 | + |
| 59 | + /** |
| 60 | + * @throws NotPermittedException |
| 61 | + * @throws GenericFileException |
| 62 | + * @throws LockedException |
| 63 | + */ |
| 64 | + public function handle(Event $event): void { |
| 65 | + if (!($event instanceof MetadataLiveEvent) |
| 66 | + && !($event instanceof MetadataBackgroundEvent)) { |
| 67 | + return; |
| 68 | + } |
| 69 | + |
| 70 | + $file = $event->getNode(); |
| 71 | + if (!($file instanceof File)) { |
| 72 | + return; |
| 73 | + } |
| 74 | + |
| 75 | + // too heavy to run on the live thread, request a rerun as a background job |
| 76 | + if ($event instanceof MetadataLiveEvent) { |
| 77 | + $event->requestBackgroundJob(); |
| 78 | + return; |
| 79 | + } |
| 80 | + |
| 81 | + $image = false; |
| 82 | + try { |
| 83 | + // using preview image to generate the blurhash |
| 84 | + $preview = $this->preview->getPreview($file, 256, 256); |
| 85 | + $image = imagecreatefromstring($preview->getContent()); |
| 86 | + } catch (NotFoundException $e) { |
| 87 | + // https://github.com/nextcloud/server/blob/9d70fd3e64b60a316a03fb2b237891380c310c58/lib/private/legacy/OC_Image.php#L668 |
| 88 | + // The preview system can fail on huge picture, in that case we use our own image resizer. |
| 89 | + if (str_starts_with($file->getMimetype(), 'image/')) { |
| 90 | + $image = $this->resizedImageFromFile($file); |
| 91 | + } |
| 92 | + } |
| 93 | + |
| 94 | + if ($image === false) { |
| 95 | + return; |
| 96 | + } |
| 97 | + |
| 98 | + $metadata = $event->getMetadata(); |
| 99 | + $metadata->setString('blurhash', $this->generateBlurHash($image)); |
| 100 | + } |
| 101 | + |
| 102 | + /** |
| 103 | + * @param File $file |
| 104 | + * |
| 105 | + * @return GdImage|false |
| 106 | + * @throws GenericFileException |
| 107 | + * @throws NotPermittedException |
| 108 | + * @throws LockedException |
| 109 | + */ |
| 110 | + private function resizedImageFromFile(File $file): GdImage|false { |
| 111 | + $image = imagecreatefromstring($file->getContent()); |
| 112 | + if ($image === false) { |
| 113 | + return false; |
| 114 | + } |
| 115 | + |
| 116 | + $currX = imagesx($image); |
| 117 | + $currY = imagesy($image); |
| 118 | + |
| 119 | + if ($currX > $currY) { |
| 120 | + $newX = self::RESIZE_BOXSIZE; |
| 121 | + $newY = intval($currY * $newX / $currX); |
| 122 | + } else { |
| 123 | + $newY = self::RESIZE_BOXSIZE; |
| 124 | + $newX = intval($currX * $newY / $currY); |
| 125 | + } |
| 126 | + |
| 127 | + $newImage = imagescale($image, $newX, $newY); |
| 128 | + return ($newImage !== false) ? $newImage : $image; |
| 129 | + } |
| 130 | + |
| 131 | + /** |
| 132 | + * @param GdImage $image |
| 133 | + * |
| 134 | + * @return string |
| 135 | + */ |
| 136 | + public function generateBlurHash(GdImage $image): string { |
| 137 | + $width = imagesx($image); |
| 138 | + $height = imagesy($image); |
| 139 | + |
| 140 | + $pixels = []; |
| 141 | + for ($y = 0; $y < $height; ++$y) { |
| 142 | + $row = []; |
| 143 | + for ($x = 0; $x < $width; ++$x) { |
| 144 | + $index = imagecolorat($image, $x, $y); |
| 145 | + $colors = imagecolorsforindex($image, $index); |
| 146 | + $row[] = [$colors['red'], $colors['green'], $colors['blue']]; |
| 147 | + } |
| 148 | + |
| 149 | + $pixels[] = $row; |
| 150 | + } |
| 151 | + |
| 152 | + return Blurhash::encode($pixels, self::COMPONENTS_X, self::COMPONENTS_Y); |
| 153 | + } |
| 154 | + |
| 155 | + /** |
| 156 | + * @param IEventDispatcher $eventDispatcher |
| 157 | + * |
| 158 | + * @return void |
| 159 | + */ |
| 160 | + public static function loadListeners(IEventDispatcher $eventDispatcher): void { |
| 161 | + $eventDispatcher->addServiceListener(MetadataLiveEvent::class, self::class); |
| 162 | + $eventDispatcher->addServiceListener(MetadataBackgroundEvent::class, self::class); |
| 163 | + } |
| 164 | +} |
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