From f9b806eaa18c7bdaedb36a073a450f5fa6417d2e Mon Sep 17 00:00:00 2001
From: George Claghorn <george@basecamp.com>
Date: Wed, 31 Jan 2018 15:43:29 -0500
Subject: Swap encoded image width and height if angle is 90 or 270 degrees

---
 .../lib/active_storage/analyzer/image_analyzer.rb     |  12 +++++++++++-
 activestorage/test/analyzer/image_analyzer_test.rb    |  17 +++++++++++++++--
 activestorage/test/fixtures/files/racecar_rotated.jpg | Bin 0 -> 1124060 bytes
 3 files changed, 26 insertions(+), 3 deletions(-)
 create mode 100644 activestorage/test/fixtures/files/racecar_rotated.jpg

diff --git a/activestorage/lib/active_storage/analyzer/image_analyzer.rb b/activestorage/lib/active_storage/analyzer/image_analyzer.rb
index 5231168a7c..7342178eff 100644
--- a/activestorage/lib/active_storage/analyzer/image_analyzer.rb
+++ b/activestorage/lib/active_storage/analyzer/image_analyzer.rb
@@ -3,6 +3,8 @@
 module ActiveStorage
   # Extracts width and height in pixels from an image blob.
   #
+  # If the image contains EXIF data indicating its angle is 90 or 270 degrees, its width and height are swapped for convenience.
+  #
   # Example:
   #
   #   ActiveStorage::Analyzer::ImageAnalyzer.new(blob).metadata
@@ -17,7 +19,11 @@ module ActiveStorage
 
     def metadata
       read_image do |image|
-        { width: image.width, height: image.height }
+        if rotated_image?(image)
+          { width: image.height, height: image.width }
+        else
+          { width: image.width, height: image.height }
+        end
       end
     rescue LoadError
       logger.info "Skipping image analysis because the mini_magick gem isn't installed"
@@ -31,5 +37,9 @@ module ActiveStorage
           yield MiniMagick::Image.new(file.path)
         end
       end
+
+      def rotated_image?(image)
+        %w[ RightTop LeftBottom ].include?(image["orientation"])
+      end
   end
 end
diff --git a/activestorage/test/analyzer/image_analyzer_test.rb b/activestorage/test/analyzer/image_analyzer_test.rb
index 0d9f24c5c1..f04ed63c3c 100644
--- a/activestorage/test/analyzer/image_analyzer_test.rb
+++ b/activestorage/test/analyzer/image_analyzer_test.rb
@@ -8,7 +8,15 @@ require "active_storage/analyzer/image_analyzer"
 class ActiveStorage::Analyzer::ImageAnalyzerTest < ActiveSupport::TestCase
   test "analyzing a JPEG image" do
     blob = create_file_blob(filename: "racecar.jpg", content_type: "image/jpeg")
-    metadata = blob.tap(&:analyze).metadata
+    metadata = extract_metadata_from(blob)
+
+    assert_equal 4104, metadata[:width]
+    assert_equal 2736, metadata[:height]
+  end
+
+  test "analyzing a rotated JPEG image" do
+    blob = create_file_blob(filename: "racecar_rotated.jpg", content_type: "image/jpeg")
+    metadata = extract_metadata_from(blob)
 
     assert_equal 4104, metadata[:width]
     assert_equal 2736, metadata[:height]
@@ -16,9 +24,14 @@ class ActiveStorage::Analyzer::ImageAnalyzerTest < ActiveSupport::TestCase
 
   test "analyzing an SVG image without an XML declaration" do
     blob = create_file_blob(filename: "icon.svg", content_type: "image/svg+xml")
-    metadata = blob.tap(&:analyze).metadata
+    metadata = extract_metadata_from(blob)
 
     assert_equal 792, metadata[:width]
     assert_equal 584, metadata[:height]
   end
+
+  private
+    def extract_metadata_from(blob)
+      blob.tap(&:analyze).metadata
+    end
 end
diff --git a/activestorage/test/fixtures/files/racecar_rotated.jpg b/activestorage/test/fixtures/files/racecar_rotated.jpg
new file mode 100644
index 0000000000..89e6d54f98
Binary files /dev/null and b/activestorage/test/fixtures/files/racecar_rotated.jpg differ
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