Added get_ifd method to access embedded IFDs

Tests/test_imagefile.py

@@ -284,7 +284,7 @@ class TestPyDecoder(PillowTestCase):
     @unittest.skipIf(not HAVE_WEBP or not _webp.HAVE_WEBPANIM,
                      "WebP support not installed with animation")
     def test_exif_webp(self):
-        im = Image.open("Tests/images/hopper.webp")  # WebP
+        im = Image.open("Tests/images/hopper.webp")
         exif = im.getexif()
         self.assertEqual(exif, {})
 
@@ -321,5 +321,15 @@ class TestPyDecoder(PillowTestCase):
         self.assertEqual(reloaded_exif, {
             258: 8,
             40963: 455,
-            305: 'Pillow test'
+            305: 'Pillow test',
+        })
+
+    def test_exif_interop(self):
+        im = Image.open("Tests/images/flower.jpg")
+        exif = im.getexif()
+        self.assertEqual(exif.get_ifd(0xa005), {
+            1: 'R98',
+            2: b'0100',
+            4097: 2272,
+            4098: 1704,
         })

src/PIL/ImageFile.py

@@ -689,6 +689,7 @@ class PyDecoder(object):
 
 class Exif(MutableMapping):
     _data = {}
+    _ifds = {}
     endian = "<"
 
     def _fixup_dict(self, src_dict):
@@ -704,6 +705,19 @@ class Exif(MutableMapping):
 
         return {k: _fixup(v) for k, v in src_dict.items()}
 
+    def _get_ifd_dict(self, fp, head, tag):
+        try:
+            # an offset pointer to the location of the nested embedded ifd.
+            # It should be a long, but may be corrupted.
+            fp.seek(self._data[tag])
+        except (KeyError, TypeError):
+            pass
+        else:
+            from . import TiffImagePlugin
+            info = TiffImagePlugin.ImageFileDirectory_v1(head)
+            info.load(fp)
+            return self._fixup_dict(info)
+
     def load(self, data):
         # Extract EXIF information.  This is highly experimental,
         # and is likely to be replaced with something better in a future
@@ -720,30 +734,25 @@ class Exif(MutableMapping):
         fp.seek(info.next)
         info.load(fp)
         self._data = dict(self._fixup_dict(info))
+
         # get exif extension
-        try:
-            # exif field 0x8769 is an offset pointer to the location
-            # of the nested embedded exif ifd.
-            # It should be a long, but may be corrupted.
-            fp.seek(self._data[0x8769])
-        except (KeyError, TypeError):
-            pass
-        else:
-            info = TiffImagePlugin.ImageFileDirectory_v1(head)
-            info.load(fp)
-            self._data.update(self._fixup_dict(info))
+        ifd = self._get_ifd_dict(fp, head, 0x8769)
+        if ifd:
+            self._data.update(ifd)
+            self._ifds[0x8769] = ifd
+
         # get gpsinfo extension
-        try:
-            # exif field 0x8825 is an offset pointer to the location
-            # of the nested embedded gps exif ifd.
-            # It should be a long, but may be corrupted.
-            fp.seek(self._data[0x8825])
-        except (KeyError, TypeError):
-            pass
-        else:
-            info = TiffImagePlugin.ImageFileDirectory_v1(head)
-            info.load(fp)
-            self._data[0x8825] = self._fixup_dict(info)
+        ifd = self._get_ifd_dict(fp, head, 0x8825)
+        if ifd:
+            self._data[0x8825] = ifd
+            self._ifds[0x8825] = ifd
+
+        for tag in [
+            0xa005,  # interop
+        ]:
+            ifd = self._get_ifd_dict(fp, head, tag)
+            if ifd:
+                self._ifds[tag] = ifd
 
     def toBytes(self, offset=0):
         from . import TiffImagePlugin
@@ -756,6 +765,9 @@ class Exif(MutableMapping):
             ifd[tag] = value
         return b"Exif\x00\x00"+head+ifd.toBytes(offset)
 
+    def get_ifd(self, tag):
+        return self._ifds.get(tag, {})
+
     def __str__(self):
         return str(self._data)