From: Dan Brown <redacted>
Date: Sun, 9 Jun 2024 15:58:23 +0000 (+0100)
Subject: Images: Updated GIF handling to use native methods
X-Git-Tag: v24.05.2~1^2~7
X-Git-Url: http://source.bookstackapp.com/bookstack/commitdiff_plain/3406846c82bd2322687dae5b7d38045746219edd

Images: Updated GIF handling to use native methods

Changes GIF image thumbnail handling to direcly load via gd instead of
going through interventions own handling (which supports frames) since
we don't need animation for our thumbnails, and since performance issues
could arise with GIFs that have large frame counts.

For #5029
---

diff --git a/app/Uploads/ImageResizer.php b/app/Uploads/ImageResizer.php
index d09177fff..fa6b1cac2 100644
--- a/app/Uploads/ImageResizer.php
+++ b/app/Uploads/ImageResizer.php
@@ -7,11 +7,13 @@ use Exception;
 use GuzzleHttp\Psr7\Utils;
 use Illuminate\Support\Facades\Cache;
 use Intervention\Image\Decoders\BinaryImageDecoder;
+use Intervention\Image\Drivers\Gd\Decoders\NativeObjectDecoder;
 use Intervention\Image\Drivers\Gd\Driver;
 use Intervention\Image\Encoders\AutoEncoder;
 use Intervention\Image\Encoders\PngEncoder;
 use Intervention\Image\Interfaces\ImageInterface as InterventionImage;
 use Intervention\Image\ImageManager;
+use Intervention\Image\Origin;
 
 class ImageResizer
 {
@@ -99,7 +101,7 @@ class ImageResizer
         }
 
         // If not in cache and thumbnail does not exist, generate thumb and cache path
-        $thumbData = $this->resizeImageData($imageData, $width, $height, $keepRatio);
+        $thumbData = $this->resizeImageData($imageData, $width, $height, $keepRatio, $this->getExtension($image));
         $disk->put($thumbFilePath, $thumbData, true);
         Cache::put($thumbCacheKey, $thumbFilePath, static::THUMBNAIL_CACHE_TIME);
 
@@ -120,7 +122,7 @@ class ImageResizer
         ?string $format = null,
     ): string {
         try {
-            $thumb = $this->interventionFromImageData($imageData);
+            $thumb = $this->interventionFromImageData($imageData, $format);
         } catch (Exception $e) {
             throw new ImageUploadException(trans('errors.cannot_create_thumbs'));
         }
@@ -154,11 +156,23 @@ class ImageResizer
      * Performs some manual library usage to ensure image is specifically loaded
      * from given binary data instead of data being misinterpreted.
      */
-    protected function interventionFromImageData(string $imageData): InterventionImage
+    protected function interventionFromImageData(string $imageData, ?string $fileType): InterventionImage
     {
         $manager = new ImageManager(new Driver());
 
-        return $manager->read($imageData, BinaryImageDecoder::class);
+        // Ensure gif images are decoded natively instead of deferring to intervention GIF
+        // handling since we don't need the added animation support.
+        $isGif = $fileType === 'gif';
+        $decoder = $isGif ? NativeObjectDecoder::class : BinaryImageDecoder::class;
+        $input = $isGif ? @imagecreatefromstring($imageData) : $imageData;
+
+        $image = $manager->read($input, $decoder);
+
+        if ($isGif) {
+            $image->setOrigin(new Origin('image/gif'));
+        }
+
+        return $image;
     }
 
     /**
@@ -209,7 +223,15 @@ class ImageResizer
      */
     protected function isGif(Image $image): bool
     {
-        return strtolower(pathinfo($image->path, PATHINFO_EXTENSION)) === 'gif';
+        return $this->getExtension($image) === 'gif';
+    }
+
+    /**
+     * Get the extension for the given image, normalised to lower-case.
+     */
+    protected function getExtension(Image $image): string
+    {
+        return strtolower(pathinfo($image->path, PATHINFO_EXTENSION));
     }
 
     /**
diff --git a/tests/Uploads/ImageTest.php b/tests/Uploads/ImageTest.php
index d24b6202b..db500f606 100644
--- a/tests/Uploads/ImageTest.php
+++ b/tests/Uploads/ImageTest.php
@@ -599,6 +599,40 @@ class ImageTest extends TestCase
         $this->files->deleteAtRelativePath($relPath);
     }
 
+    public function test_gif_thumbnail_generation()
+    {
+        $this->asAdmin();
+        $originalFile = $this->files->testFilePath('animated.gif');
+        $originalFileSize = filesize($originalFile);
+
+        $imgDetails = $this->files->uploadGalleryImageToPage($this, $this->entities->page(), 'animated.gif');
+        $relPath = $imgDetails['path'];
+
+        $this->assertTrue(file_exists(public_path($relPath)), 'Uploaded image found at path: ' . public_path($relPath));
+        $galleryThumb = $imgDetails['response']->thumbs->gallery;
+        $displayThumb = $imgDetails['response']->thumbs->display;
+
+        // Ensure display thumbnail is original image
+        $this->assertStringEndsWith($imgDetails['path'], $displayThumb);
+        $this->assertStringNotContainsString('thumbs', $displayThumb);
+
+        // Ensure gallery thumbnail is reduced image (single frame)
+        $galleryThumbRelPath = implode('/', array_slice(explode('/', $galleryThumb), 3));
+        $galleryThumbPath = public_path($galleryThumbRelPath);
+        $galleryFileSize = filesize($galleryThumbPath);
+
+        // Basic scan of GIF content to check frame count
+        $originalFrameCount = count(explode("\x00\x21\xF9", file_get_contents($originalFile)));
+        $galleryFrameCount = count(explode("\x00\x21\xF9", file_get_contents($galleryThumbPath)));
+
+        $this->files->deleteAtRelativePath($relPath);
+        $this->files->deleteAtRelativePath($galleryThumbRelPath);
+
+        $this->assertNotEquals($originalFileSize, $galleryFileSize);
+        $this->assertEquals(3, $originalFrameCount);
+        $this->assertEquals(1, $galleryFrameCount);
+    }
+
     protected function getTestProfileImage()
     {
         $imageName = 'profile.png';
diff --git a/tests/test-data/animated.gif b/tests/test-data/animated.gif
new file mode 100644
index 000000000..13c9d0524
Binary files /dev/null and b/tests/test-data/animated.gif differ