Drop support for Pillow < 5.2.0

Pillow 5.2.0 is the first version that supports Python 3.7.

Author: bgilbert

openslide/__init__.py

@@ -331,21 +331,15 @@ def detect_format(cls, filename):
 
         If the file format is not recognized, return None."""
         try:
-            img = Image.open(filename)
-            format = img.format
-            if hasattr(img, 'close'):
-                # Pillow >= 2.5.0
-                img.close()
-            return format
+            with Image.open(filename) as img:
+                return img.format
         except OSError:
             return None
 
     def close(self):
         """Close the slide object."""
         if self._close:
-            if hasattr(self._image, 'close'):
-                # Pillow >= 2.5.0
-                self._image.close()
+            self._image.close()
             self._close = False
         self._image = None
 

tests/__init__.py

@@ -21,8 +21,6 @@
 import os
 from pathlib import Path
 
-from PIL import Image
-
 # Handle Windows-specific first-import logic here, so individual modules
 # don't have to
 if os.name == 'nt':
@@ -45,14 +43,6 @@
 
 from openslide import OpenSlideVersionError
 
-# PIL.Image cannot have zero width or height on Pillow 3.4.0 - 3.4.2
-# https://github.com/python-pillow/Pillow/issues/2259
-try:
-    Image.new('RGBA', (1, 0))
-    image_dimensions_cannot_be_zero = False
-except ValueError:
-    image_dimensions_cannot_be_zero = True
-
 
 def file_path(name):
     return Path(__file__).parent / name

tests/test_imageslide.py

@@ -17,25 +17,13 @@
 # Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 #
 
-from contextlib import contextmanager
 import unittest
 
 from PIL import Image
 
 from openslide import ImageSlide, OpenSlideCache, OpenSlideError
 
-from . import file_path, image_dimensions_cannot_be_zero, maybe_supported
-
-
-@contextmanager
-def image_open(*args, **kwargs):
-    img = Image.open(*args, **kwargs)
-    try:
-        yield img
-    finally:
-        if hasattr(img, 'close'):
-            # Pillow >= 2.5.0
-            img.close()
+from . import file_path, maybe_supported
 
 
 class TestImageWithoutOpening(unittest.TestCase):
@@ -50,13 +38,13 @@ def test_open(self):
 
     def test_open_image(self):
         # passing PIL.Image to ImageSlide
-        with image_open(file_path('boxes.png')) as img:
+        with Image.open(file_path('boxes.png')) as img:
             with ImageSlide(img) as osr:
                 self.assertEqual(osr.dimensions, (300, 250))
                 self.assertEqual(repr(osr), 'ImageSlide(%r)' % img)
 
     def test_operations_on_closed_handle(self):
-        with image_open(file_path('boxes.png')) as img:
+        with Image.open(file_path('boxes.png')) as img:
             osr = ImageSlide(img)
             osr.close()
             self.assertRaises(
@@ -102,7 +90,6 @@ def test_read_region(self):
             self.osr.read_region((-10, -10), 0, (400, 400)).size, (400, 400)
         )
 
-    @unittest.skipIf(image_dimensions_cannot_be_zero, 'Pillow issue #2259')
     def test_read_region_size_dimension_zero(self):
         self.assertEqual(self.osr.read_region((0, 0), 0, (400, 0)).size, (400, 0))
 

tests/test_openslide.py

@@ -31,7 +31,7 @@
     OpenSlideUnsupportedFormatError,
 )
 
-from . import file_path, image_dimensions_cannot_be_zero, maybe_supported
+from . import file_path, maybe_supported
 
 
 class TestCache(unittest.TestCase):
@@ -128,7 +128,6 @@ def test_read_region(self):
             self.osr.read_region((-10, -10), 1, (400, 400)).size, (400, 400)
         )
 
-    @unittest.skipIf(image_dimensions_cannot_be_zero, 'Pillow issue #2259')
     def test_read_region_size_dimension_zero(self):
         self.assertEqual(self.osr.read_region((0, 0), 1, (400, 0)).size, (400, 0))
 
@@ -141,7 +140,7 @@ def test_read_region_bad_size(self):
         )
 
     @unittest.skipIf(sys.maxsize < 1 << 32, '32-bit Python')
-    # Broken on Pillow >= 3.4.0, < 6.2.0.
+    # Broken on Pillow < 6.2.0.
     # https://github.com/python-pillow/Pillow/issues/3963
     @unittest.skipIf(
         [int(i) for i in getattr(Image, '__version__', '0').split('.')] < [6, 2, 0],