JPEG: ignore invalid values for the the orientation tag (closes #38)

README.rst

@@ -56,7 +56,7 @@ Changelog
 
 * **[NEXT]** (changes on ``master`` that have not been released yet):
 
-  * *nothing yet*
+  * JPEG: ignore invalid values for the the orientation tag (#38)
 
 * **1.1.0:**
 

test/test_image_encoders_jpeg.py

@@ -35,5 +35,25 @@ class Test_open_jpeg(object):
             assert r2 < 5 and g2 > 250 and b2 < 5  # ~lime
 
             # Check if the blue square is at bottom-right corner
-            r3, g3, b3 = image.getpixel((255 - 8, 340 - 8))
+            r3, g3, b3 = image.getpixel((255 - 8, 341 - 8))
+            assert r3 < 5 and g3 < 5 and b3 > 250  # ~blue
+
+    def test_jpeg_orientation_invalid(self):
+        with open("test/images/orientation/invalid.jpg", "rb") as image_file:
+            image = jpeg.open_jpeg(image_file)
+
+            # Test image size
+            assert image.width == 341
+            assert image.height == 256
+
+            # Check if the red square is at top-right corner
+            r1, g1, b1 = image.getpixel((341 - 8, 8))
+            assert r1 > 250 and g1 < 5 and b1 < 5  # ~red
+
+            # Check if the green square is at bottom-right corner
+            r2, g2, b2 = image.getpixel((341 - 8, 255 - 8))
+            assert r2 < 5 and g2 > 250 and b2 < 5  # ~lime
+
+            # Check if the blue square is at bottom-left corner
+            r3, g3, b3 = image.getpixel((8, 255 - 8))
             assert r3 < 5 and g3 < 5 and b3 > 250  # ~blue

yoga/image/encoders/jpeg.py

@@ -3,6 +3,19 @@ import mozjpeg_lossless_optimization
 from PIL import Image
 
 
+EXIF_TAG_ORIENTATION = 0x0112
+ORIENTATION_OPERATIONS = {
+    1: [],
+    2: [Image.FLIP_LEFT_RIGHT],
+    3: [Image.ROTATE_180],
+    4: [Image.FLIP_TOP_BOTTOM],
+    5: [Image.FLIP_LEFT_RIGHT, Image.ROTATE_90],
+    6: [Image.ROTATE_270],
+    7: [Image.FLIP_LEFT_RIGHT, Image.ROTATE_270],
+    8: [Image.ROTATE_90],
+}
+
+
 def is_jpeg(file_bytes):
     """Whether or not the given bytes represent a JPEG file.
 
@@ -45,22 +58,13 @@ def open_jpeg(image_file):
     :param file-like image_file: the image file.
     :rtype: PIL.Image
     """
-    EXIF_TAG_ORIENTATION = 274
-    ORIENTATION_OPERATIONS = {
-        1: [],
-        2: [Image.FLIP_LEFT_RIGHT],
-        3: [Image.ROTATE_180],
-        4: [Image.FLIP_TOP_BOTTOM],
-        5: [Image.FLIP_LEFT_RIGHT, Image.ROTATE_90],
-        6: [Image.ROTATE_270],
-        7: [Image.FLIP_LEFT_RIGHT, Image.ROTATE_270],
-        8: [Image.ROTATE_90],
-    }
-
     image = Image.open(image_file)
     exif = image.getexif()
 
-    if EXIF_TAG_ORIENTATION in exif:
+    if (
+        EXIF_TAG_ORIENTATION in exif
+        and exif[EXIF_TAG_ORIENTATION] in ORIENTATION_OPERATIONS
+    ):
         orientation = exif[EXIF_TAG_ORIENTATION]
         for operation in ORIENTATION_OPERATIONS[orientation]:
             image = image.transpose(operation)