From 77f68861c67d4cedf75025c085a6c5e6b40c4b7e Mon Sep 17 00:00:00 2001
From: Stefan van der Walt <stefan@sun.ac.za>
Date: Mon, 12 Dec 2011 15:57:34 -0800
Subject: [PATCH] BUG: Correctly load bi-level images via PIL.

---
 skimage/data/checker_bilevel.png  | Bin 0 -> 278 bytes
 skimage/io/_plugins/pil_plugin.py |   5 +++--
 skimage/io/tests/test_pil.py      |   8 ++++++++
 3 files changed, 11 insertions(+), 2 deletions(-)
 create mode 100644 skimage/data/checker_bilevel.png

diff --git a/skimage/data/checker_bilevel.png b/skimage/data/checker_bilevel.png
new file mode 100644
index 0000000000000000000000000000000000000000..c0f1c5dc0b99bbb62f8369fad8e293d38f4d3284
GIT binary patch
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literal 0
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diff --git a/skimage/io/_plugins/pil_plugin.py b/skimage/io/_plugins/pil_plugin.py
index 5082b831..90fffdc4 100644
--- a/skimage/io/_plugins/pil_plugin.py
+++ b/skimage/io/_plugins/pil_plugin.py
@@ -21,8 +21,9 @@ def imread(fname, dtype=None):
             im = im.convert('L')
         else:
             im = im.convert('RGB')
-
-    if im.mode.startswith('I;16'):
+    elif im.mode == '1':
+        im = im.convert('L')
+    elif im.mode == 'I;16':
         shape = im.size
         dtype = '>u2' if im.mode.endswith('B') else '<u2'
         im = np.fromstring(im.tostring(), dtype)
diff --git a/skimage/io/tests/test_pil.py b/skimage/io/tests/test_pil.py
index 8cafed10..058e1dc9 100644
--- a/skimage/io/tests/test_pil.py
+++ b/skimage/io/tests/test_pil.py
@@ -43,6 +43,14 @@ def test_palette_is_gray():
     color = Image.open(os.path.join(data_dir, 'palette_color.png'))
     assert not _palette_is_grayscale(color)
 
+@skipif(not PIL_available)
+def test_bilevel():
+    expected = np.zeros((10, 10))
+    expected[::2] = 255
+
+    img = imread(os.path.join(data_dir, 'checker_bilevel.png'))
+    assert_array_equal(img, expected)
+
 class TestSave:
     def roundtrip(self, dtype, x, scaling=1):
         f = NamedTemporaryFile(suffix='.png')