__setitem__ working for writing an entire image at once

docs/source/how_do_i.rst

@@ -347,7 +347,7 @@ image isn't square. ::
     >>> alpha[mask] = 0
     >>> rgba = np.concatenate((rgb, alpha), axis=2)
     >>> jp2 = Jp2k('tmp.jp2', 'wb')
-    >>> jp2.write(rgba)
+    >>> jp2[:] = rgba
 
 Next we need to specify what types of channels we have.
 The first three channels are color channels, but we identify the fourth as
@@ -447,7 +447,7 @@ http://photojournal.jpl.nasa.gov/tiff/PIA17145.tif info JPEG 2000::
     >>> image = skimage.io.imread('PIA17145.tif')
     >>> from glymur import Jp2k
     >>> jp2 = Jp2k('PIA17145.jp2', 'wb')
-    >>> jp2.write(image)
+    >>> jp2[:] = image
 
 Next you can extract the XMP metadata.
 

glymur/jp2k.py

@@ -759,6 +759,22 @@ class Jp2k(Jp2kBox):
 
         return boxes
 
+    def __setitem__(self, index, data):
+        """
+        Slicing protocol.
+        """
+        if isinstance(index, slice) and (
+                index.start == None and
+                index.stop == None and
+                index.step == None):
+            # Case of jp2[:] = data, i.e. write the entire image.
+            #
+            # Should have a slice object where start = stop = step = None
+            self.write(data)
+        else:
+            msg = "Images currently must be written entirely at once."
+            raise TypeError(msg)
+
     def __getitem__(self, pargs):
         """
         Slicing protocol.

glymur/test/test_jp2k.py

@@ -75,38 +75,50 @@ class TestSliceProtocolBaseWrite(SliceProtocolBase):
         with tempfile.NamedTemporaryFile(suffix='.j2k') as tfile:
             j = Jp2k(tfile.name, 'wb')
             j[:] = self.j2k_data
-            expected = j.read()
+            actual = j.read()
 
         np.testing.assert_array_equal(actual, expected)
 
+    def test_cannot_write_with_non_default_single_slice(self):
+        with tempfile.NamedTemporaryFile(suffix='.j2k') as tfile:
+            j = Jp2k(tfile.name, 'wb')
+            with self.assertRaises(TypeError):
+                j[slice(None, 0)] = self.j2k_data
+            with self.assertRaises(TypeError):
+                j[slice(0, None)] = self.j2k_data
+            with self.assertRaises(TypeError):
+                j[slice(0, 0, None)] = self.j2k_data
+            with self.assertRaises(TypeError):
+                j[slice(0, 640)] = self.j2k_data
+
     def test_cannot_write_a_row(self):
         with tempfile.NamedTemporaryFile(suffix='.j2k') as tfile:
             j = Jp2k(tfile.name, 'wb')
-            with self.assertRaises(IOError):
+            with self.assertRaises(TypeError):
                 j[5] = self.j2k_data
 
     def test_cannot_write_a_pixel(self):
         with tempfile.NamedTemporaryFile(suffix='.j2k') as tfile:
             j = Jp2k(tfile.name, 'wb')
-            with self.assertRaises(IOError):
+            with self.assertRaises(TypeError):
                 j[25, 35] = self.j2k_data[25, 35]
 
     def test_cannot_write_a_column(self):
         with tempfile.NamedTemporaryFile(suffix='.j2k') as tfile:
             j = Jp2k(tfile.name, 'wb')
-            with self.assertRaises(IOError):
+            with self.assertRaises(TypeError):
                 j[:, 25, :] = self.j2k_data[:, :25, :]
 
     def test_cannot_write_a_band(self):
         with tempfile.NamedTemporaryFile(suffix='.j2k') as tfile:
             j = Jp2k(tfile.name, 'wb')
-            with self.assertRaises(IOError):
+            with self.assertRaises(TypeError):
                 j[:, :, 0] = self.j2k_data[:, :, 0]
 
     def test_cannot_write_a_subarray(self):
         with tempfile.NamedTemporaryFile(suffix='.j2k') as tfile:
             j = Jp2k(tfile.name, 'wb')
-            with self.assertRaises(IOError):
+            with self.assertRaises(TypeError):
                 j[:25, :45, :] = self.j2k_data[:25, :25, :]