Made display thumbnail generation use original data if smaller

Thumbnail generation would sometimes create a file larger than the
original, if the original was already well optimized, therefore making
the thumbnail counter-productive. This change compares the sizes of the
original and the generated thumbnail, and uses the smaller of the two if
the thumbnail does not change the aspect ratio of the image.

Fixes #1751

tests/Uploads/ImageTest.php

@@ -36,6 +36,30 @@ class ImageTest extends TestCase
         ]);
     }
 
+    public function test_image_display_thumbnail_generation_does_not_increase_image_size()
+    {
+        $page = Page::first();
+        $admin = $this->getAdmin();
+        $this->actingAs($admin);
+
+        $originalFile = $this->getTestImageFilePath('compressed.png');
+        $originalFileSize = filesize($originalFile);
+        $imgDetails = $this->uploadGalleryImage($page, 'compressed.png');
+        $relPath = $imgDetails['path'];
+
+        $this->assertTrue(file_exists(public_path($relPath)), 'Uploaded image found at path: '. public_path($relPath));
+        $displayImage = $imgDetails['response']->thumbs->display;
+
+        $displayImageRelPath = implode('/', array_slice(explode('/', $displayImage), 3));
+        $displayImagePath = public_path($displayImageRelPath);
+        $displayFileSize = filesize($displayImagePath);
+
+        $this->deleteImage($relPath);
+        $this->deleteImage($displayImageRelPath);
+
+        $this->assertEquals($originalFileSize, $displayFileSize, 'Display thumbnail generation should not increase image size');
+    }
+
     public function test_image_edit()
     {
         $editor = $this->getEditor();

tests/Uploads/UsesImages.php

@@ -10,9 +10,13 @@ trait UsesImages
      * Get the path to our basic test image.
      * @return string
      */
-    protected function getTestImageFilePath()
+    protected function getTestImageFilePath(?string $fileName = null)
     {
-        return base_path('tests/test-data/test-image.png');
+        if (is_null($fileName)) {
+            $fileName = 'test-image.png';
+        }
+        
+        return base_path('tests/test-data/' . $fileName);
     }
 
     /**
@@ -20,9 +24,9 @@ trait UsesImages
      * @param $fileName
      * @return UploadedFile
      */
-    protected function getTestImage($fileName)
+    protected function getTestImage($fileName, ?string $testDataFileName = null)
     {
-        return new UploadedFile($this->getTestImageFilePath(), $fileName, 'image/png', 5238, null, true);
+        return new UploadedFile($this->getTestImageFilePath($testDataFileName), $fileName, 'image/png', 5238, null, true);
     }
 
     /**
@@ -52,9 +56,9 @@ trait UsesImages
      * @param string $contentType
      * @return \Illuminate\Foundation\Testing\TestResponse
      */
-    protected function uploadImage($name, $uploadedTo = 0, $contentType = 'image/png')
+    protected function uploadImage($name, $uploadedTo = 0, $contentType = 'image/png', ?string $testDataFileName = null)
     {
-        $file = $this->getTestImage($name);
+        $file = $this->getTestImage($name, $testDataFileName);
         return $this->withHeader('Content-Type', $contentType)
             ->call('POST', '/images/gallery', ['uploaded_to' => $uploadedTo], [], ['file' => $file], []);
     }
@@ -66,22 +70,23 @@ trait UsesImages
      * @param Page|null $page
      * @return array
      */
-    protected function uploadGalleryImage(Page $page = null)
+    protected function uploadGalleryImage(Page $page = null, ?string $testDataFileName = null)
     {
         if ($page === null) {
             $page = Page::query()->first();
         }
 
-        $imageName = 'first-image.png';
+        $imageName = $testDataFileName ?? 'first-image.png';
         $relPath = $this->getTestImagePath('gallery', $imageName);
         $this->deleteImage($relPath);
 
-        $upload = $this->uploadImage($imageName, $page->id);
+        $upload = $this->uploadImage($imageName, $page->id, 'image/png', $testDataFileName);
         $upload->assertStatus(200);
         return [
             'name' => $imageName,
             'path' => $relPath,
-            'page' => $page
+            'page' => $page,
+            'response' => json_decode($upload->getContent()),
         ];
     }