Standardize frame metadata.

Any tile source that exposes frames will have a frames list.  This list
now will always contain Frame and Index values, and, where appropriate
IndexC, IndexT, IndexZ, IndexXY values.  The top-level metadata will
always have IndexRange and IndexStride entries.  When known, the
top-level metadata will have channels and channelmap entries with
channel names.

large_image/tilesource/base.py

@@ -1454,6 +1454,28 @@ def canRead(cls, *args, **kwargs):
         return False
 
     def getMetadata(self):
+        """
+        Return metadata about this tile source.  In addition to the keys that
+        are listed in this template function, tile sources that expose multiple
+        frames will also contain:
+        - frames: a list of frames.  Each frame entry is a dictionary with
+          - Frame: a 0-values frame index (the location in the list)
+          - Channel (optional): the name of the channel, if known
+          - IndexC (optional if unique): a 0-based index into the channel list
+          - IndexT (optional if unique): a 0-based index for time values
+          - IndexZ (optional if unique): a 0-based index for z values
+          - IndexXY (optional if unique): a 0-based index for view (xy) values
+          - Index: a 0-based index of non-channel unique sets.  If the frames
+              vary only by channel and are adjacent, they will have the same
+              index.
+        - IndexRange: a dictionary of the number of unique index values from
+            frames if greater than 1 (e.g., if an entry like IndexXY is not
+            present, then all frames either do not have that value or have a
+            value of 0).
+        - channels (optional): if known, a list of channel names
+        - channelmap (optional): if known, a dictionary of channel names with
+            their offset into the channel list.
+        """
         mag = self.getNativeMagnification()
         return {
             'levels': self.levels,

sources/nd2/large_image_source_nd2/__init__.py

@@ -259,13 +259,17 @@ def getMetadata(self):  # noqa
         # }
         axes = self._nd2.iter_axes[::-1]
         result['frames'] = frames = []
+        maxref = {}
         for idx in range(len(self._nd2)):
-            frame = {'Frame': idx, 'TheZ': 0, 'TheV': 0}
+            frame = {'Frame': idx, 'IndexZ': 0, 'IndexXY': 0}
             basis = 1
             ref = {}
             for axis in axes:
                 ref[axis] = (idx // basis) % sizes[axis]
-                frame['The' + axis.upper()] = (idx // basis) % sizes[axis]
+                frame['Index' + (axis.upper() if axis != 'v' else 'XY')] = (
+                    idx // basis) % sizes[axis]
+                if ref[axis] + 1 > maxref.get(axis, 0):
+                    maxref[axis] = ref[axis] + 1
                 basis *= sizes.get(axis, 1)
             if ('channels' in self._metadata and 'c' in ref and
                     ref['c'] < len(self._metadata['channels'])):
@@ -289,11 +293,24 @@ def getMetadata(self):  # noqa
             ]:
                 if mkey in self._metadata:
                     frame[fkey] = self._metadata[mkey][cdidx % len(self._metadata[mkey])]
-            frame['IndexXY'] = ref.get('v', 0)
-            frame['IndexZ'] = ref.get('z', 0)
             frames.append(frame)
             if self._framecount and len(frames) == self._framecount:
                 break
+        if ('channels' in self._metadata and
+                len(self._metadata['channels']) >= maxref.get('c', 1) and
+                len(set(self._metadata['channels'])) == len(self._metadata['channels'])):
+            result['channels'] = self._metadata['channels'][:maxref.get('c', 1)]
+            result['channelmap'] = {
+                cname: c for c, cname in enumerate(self._metadata['channels'][:maxref.get('c', 1)])}
+        if any(val > 1 for val in maxref.values()):
+            result['IndexRange'] = {
+                'Index' + (axis.upper() if axis != 'v' else 'XY'): value
+                for axis, value in maxref.items() if value > 1
+            }
+        result['IndexStride'] = {
+            key: [idx for idx, frame in enumerate(result['frames']) if frame[key] == 1][0]
+            for key in result['IndexRange']
+        }
         return result
 
     @methodcache()

sources/ometiff/large_image_source_ometiff/__init__.py

@@ -20,6 +20,7 @@
 import numpy
 import PIL.Image
 import six
+from collections import OrderedDict
 from pkg_resources import DistributionNotFound, get_distribution
 from six.moves import range
 
@@ -215,6 +216,49 @@ def getMetadata(self):
         result = super(OMETiffFileTileSource, self).getMetadata()
         # We may want to reformat the frames to standardize this across sources
         result['frames'] = self._omebase.get('Plane', self._omebase['TiffData'])
+        # Expose channel information
+        channels = []
+        for img in self._omeinfo['Image']:
+            try:
+                channels = [channel['Name'] for channel in img['Pixels']['Channel']]
+                if len(channels) > 1:
+                    break
+            except Exception:
+                pass
+        if len(set(channels)) != len(channels):
+            channels = []
+        # Standardize "TheX" to "IndexX" values
+        reftbl = OrderedDict([
+            ('TheC', 'IndexC'), ('TheZ', 'IndexZ'), ('TheT', 'IndexT'),
+            ('FirstC', 'IndexC'), ('FirstZ', 'IndexZ'), ('FirstT', 'IndexT'),
+        ])
+        maxref = {}
+        index = 0
+        for idx, frame in enumerate(result['frames']):
+            for key in reftbl:
+                if key in frame and not reftbl[key] in frame:
+                    frame[reftbl[key]] = int(frame[key])
+                    if frame[reftbl[key]] + 1 > maxref.get(reftbl[key], 0):
+                        maxref[reftbl[key]] = frame[reftbl[key]] + 1
+            frame['Frame'] = idx
+            if (idx and (
+                    frame.get('IndexV') != result['frames'][idx - 1].get('IndexV') or
+                    frame.get('IndexZ') != result['frames'][idx - 1].get('IndexZ'))):
+                index += 1
+            frame['Index'] = index
+        if any(val > 1 for val in maxref.values()):
+            result['IndexRange'] = {key: value for key, value in maxref.items() if value > 1}
+            result['IndexStride'] = {
+                key: [idx for idx, frame in enumerate(result['frames']) if frame[key] == 1][0]
+                for key in result['IndexRange']
+            }
+        # Add channel information
+        if len(channels) >= maxref.get('IndexC', 1):
+            result['channels'] = channels[:maxref.get('IndexC', 1)]
+            result['channelmap'] = {
+                cname: c for c, cname in enumerate(channels[:maxref.get('IndexC', 1)])}
+            for frame in result['frames']:
+                frame['Channel'] = channels[frame.get('IndexC', 0)]
         result['omeinfo'] = self._omeinfo
         return result
 

test/test_source_nd2.py

@@ -19,4 +19,11 @@ def testTilesFromND2():
     assert tileMetadata['levels'] == 3
     assert tileMetadata['magnification'] == pytest.approx(47, 1)
     assert len(tileMetadata['frames']) == 232
+    assert tileMetadata['frames'][201]['Frame'] == 201
+    assert tileMetadata['frames'][201]['Index'] == 50
+    assert tileMetadata['frames'][201]['IndexC'] == 1
+    assert tileMetadata['frames'][201]['IndexXY'] == 1
+    assert tileMetadata['frames'][201]['IndexZ'] == 21
+    assert tileMetadata['channels'] == ['Brightfield', 'YFP', 'A594', 'DAPI']
+    assert tileMetadata['IndexRange'] == {'IndexC': 4, 'IndexXY': 2, 'IndexZ': 29}
     utilities.checkTilesZXY(source, tileMetadata)

test/test_source_ometiff.py

@@ -20,6 +20,10 @@ def testTilesFromOMETiff():
     assert tileMetadata['sizeY'] == 2016
     assert tileMetadata['levels'] == 3
     assert len(tileMetadata['frames']) == 3
+    assert tileMetadata['frames'][1]['Frame'] == 1
+    assert tileMetadata['frames'][1]['Index'] == 0
+    assert tileMetadata['frames'][1]['IndexC'] == 1
+    assert tileMetadata['IndexRange'] == {'IndexC': 3}
     utilities.checkTilesZXY(source, tileMetadata)
 
 
@@ -34,6 +38,12 @@ def testTilesFromStripOMETiff():
     assert tileMetadata['sizeY'] == 1022
     assert tileMetadata['levels'] == 3
     assert len(tileMetadata['frames']) == 145
+    assert tileMetadata['frames'][101]['Frame'] == 101
+    assert tileMetadata['frames'][101]['Index'] == 20
+    assert tileMetadata['frames'][101]['IndexC'] == 1
+    assert tileMetadata['frames'][101]['IndexZ'] == 20
+    assert tileMetadata['channels'] == ['Brightfield', 'CY3', 'A594', 'CY5', 'DAPI']
+    assert tileMetadata['IndexRange'] == {'IndexC': 5, 'IndexZ': 29}
     utilities.checkTilesZXY(source, tileMetadata)