Add embedded preview support for CorelDRAW (.cdr) files

lib/private/Preview/CDR.php

@@ -0,0 +1,73 @@
+<?php
+declare(strict_types=1);
+namespace OC\Preview;
+use OCP\Files\File;
+use OCP\Files\FileInfo;
+use OCP\IImage;
+use OCP\Image;
+
+class CDR extends ProviderV2 {
+	public function getMimeType(): string {
+		return '/application\/coreldraw/';
+	}
+	public function isAvailable(FileInfo $file): bool {
+		return $file->getSize() > 0;
+	}
+	public function getThumbnail(File $file, int $maxX, int $maxY): ?IImage {
+		if (!$this->isAvailable($file)) {
+			return null;
+		}
+
+		$localFile = $this->getLocalFile($file);
+
+		if ($localFile === false) {
+			return null;
+		}
+
+		$data = $this->extractThumbnail($localFile);
+		if ($data === null) {
+			return null;
+		}
+
+		$image = new Image();
+		$image->loadFromData($data);
+
+		if (!$image->valid()) {
+			return null;
+		}
+
+		$image->scaleDownToFit($maxX, $maxY);
+
+		return $image;
+	}
+	/** * Extract ONLY thumbnail (no pages) */
+	private function extractThumbnail(string $file): ?string {
+		$zip = new \ZipArchive();
+
+		if ($zip->open($file) !== true) {
+			return null;
+		}
+
+		/** * CDR files created by newer CorelDRAW versions store the embedded preview in previews/thumbnail.png.
+		    * OLD CDR format (BMP thumbnail) * metadata/thumbnails/thumbnail.bmp */
+		foreach ([
+					 'previews/thumbnail.png',
+					 'metadata/thumbnails/thumbnail.bmp',
+				 ] as $thumbnail) {
+			$idx = $zip->locateName($thumbnail);
+
+			if ($idx === false) {
+				continue;
+			}
+
+			$data = $zip->getFromIndex($idx);
+			$zip->close();
+
+			return $data === false ? null : $data;
+		}
+
+		$zip->close();
+
+		return null;
+	}
+}

lib/private/PreviewManager.php

@@ -33,6 +33,7 @@
 use OC\Preview\MSOfficeDoc;
 use OC\Preview\OpenDocument;
 use OC\Preview\PDF;
+use OC\Preview\CDR;
 use OC\Preview\Photoshop;
 use OC\Preview\PNG;
 use OC\Preview\Postscript;
@@ -278,6 +279,7 @@ protected function getEnabledDefaultProvider(): array {
 			XBitmap::class,
 			Krita::class,
 			WebP::class,
+			CDR::class,
 		];
 
 		$this->defaultProviders = $this->config->getSystemValue('enabledPreviewProviders', array_merge([
@@ -323,6 +325,7 @@ protected function registerCoreProviders(): void {
 		$this->registerCoreProvider(BMP::class, '/image\/bmp/');
 		$this->registerCoreProvider(XBitmap::class, '/image\/x-xbitmap/');
 		$this->registerCoreProvider(WebP::class, '/image\/webp/');
+		$this->registerCoreProvider(CDR::class, '/application\/coreldraw/');
 		$this->registerCoreProvider(Krita::class, '/application\/x-krita/');
 		$this->registerCoreProvider(MP3::class, '/audio\/mpeg$/');
 		$this->registerCoreProvider(OpenDocument::class, '/application\/vnd.oasis.opendocument.*/');