#11 - partial refactor

nd2reader/__init__.py

@@ -1,18 +1,25 @@
+# -*- coding: utf-8 -*-
+
+from collections import namedtuple
+from nd2reader.model import Channel
 import logging
-from nd2reader.service import BaseNd2
 from nd2reader.model import Image, ImageSet
+from nd2reader.reader import Nd2FileReader
+
+chunk = namedtuple('Chunk', ['location', 'length'])
+field_of_view = namedtuple('FOV', ['number', 'x', 'y', 'z', 'pfs_offset'])
 
 log = logging.getLogger(__name__)
 log.setLevel(logging.DEBUG)
 
 
-class Nd2(BaseNd2):
+class Nd2(Nd2FileReader):
     def __init__(self, filename):
         super(Nd2, self).__init__(filename)
 
     def get_image(self, time_index, fov, channel_name, z_level):
         image_set_number = self._calculate_image_set_number(time_index, fov, z_level)
-        timestamp, raw_image_data = self._reader.get_raw_image_data(image_set_number, self.channel_offset[channel_name])
+        timestamp, raw_image_data = self.get_raw_image_data(image_set_number, self.channel_offset[channel_name])
         return Image(timestamp, raw_image_data, fov, channel_name, z_level, self.height, self.width)
 
     def __iter__(self):
@@ -44,4 +51,73 @@ class Nd2(BaseNd2):
                     image = self.get_image(timepoint, field_of_view, channel_name, z_level)
                     if image.is_valid:
                         image_set.add(image)
-            yield image_set
+            yield image_set
+
+        self._channel_offset = None
+
+    @property
+    def height(self):
+        """
+        :return:    height of each image, in pixels
+
+        """
+        return self._metadata['ImageAttributes']['SLxImageAttributes']['uiHeight']
+
+    @property
+    def width(self):
+        """
+        :return:    width of each image, in pixels
+
+        """
+        return self._metadata['ImageAttributes']['SLxImageAttributes']['uiWidth']
+
+    @property
+    def channels(self):
+        metadata = self._metadata['ImageMetadataSeq']['SLxPictureMetadata']['sPicturePlanes']
+        try:
+            validity = self._metadata['ImageMetadata']['SLxExperiment']['ppNextLevelEx'][''][0]['ppNextLevelEx'][''][0]['pItemValid']
+        except KeyError:
+            # If none of the channels have been deleted, there is no validity list, so we just make one
+            validity = [True for i in metadata]
+        # Channel information is contained in dictionaries with the keys a0, a1...an where the number
+        # indicates the order in which the channel is stored. So by sorting the dicts alphabetically
+        # we get the correct order.
+        for (label, chan), valid in zip(sorted(metadata['sPlaneNew'].items()), validity):
+            if not valid:
+                continue
+            name = chan['sDescription']
+            exposure_time = metadata['sSampleSetting'][label]['dExposureTime']
+            camera = metadata['sSampleSetting'][label]['pCameraSetting']['CameraUserName']
+            yield Channel(name, camera, exposure_time)
+
+    @property
+    def channel_names(self):
+        """
+        A convenience method for getting an alphabetized list of channel names.
+
+        :return:    list[str]
+
+        """
+        for channel in sorted(self.channels, key=lambda x: x.name):
+            yield channel.name
+
+    @property
+    def _image_count(self):
+        return self._metadata['ImageAttributes']['SLxImageAttributes']['uiSequenceCount']
+
+    @property
+    def _sequence_count(self):
+        return self._metadata['ImageEvents']['RLxExperimentRecord']['uiCount']
+
+    @property
+    def channel_offset(self):
+        if self._channel_offset is None:
+            self._channel_offset = {}
+            for n, channel in enumerate(self.channels):
+                self._channel_offset[channel.name] = n
+        return self._channel_offset
+
+    def _calculate_image_set_number(self, time_index, fov, z_level):
+        return time_index * self.field_of_view_count * self.z_level_count + (fov * self.z_level_count + z_level)
+
+

nd2reader/model/__init__.py

@@ -1,10 +1,6 @@
 import numpy as np
 import skimage.io
 import logging
-from io import BytesIO
-import array
-import struct
-
 
 log = logging.getLogger(__name__)
 
@@ -96,172 +92,4 @@ class Image(object):
 
     def show(self):
         skimage.io.imshow(self.data)
-        skimage.io.show()
-
-
-class MetadataItem(object):
-    def __init__(self, start, data):
-        self._datatype = ord(data[start])
-        self._label_length = 2 * ord(data[start + 1])
-        self._data = data
-
-    @property
-    def is_valid(self):
-        return self._datatype > 0
-
-    @property
-    def key(self):
-        return self._data[2:self._label_length].decode("utf16").encode("utf8")
-
-    @property
-    def length(self):
-        return self._length
-
-    @property
-    def data_start(self):
-        return self._label_length + 2
-
-    @property
-    def _body(self):
-        """
-        All data after the header.
-
-        """
-        return self._data[self.data_start:]
-
-    def _get_bytes(self, count):
-        return self._data[self.data_start: self.data_start + count]
-
-    @property
-    def value(self):
-        parser = {1: self._parse_unsigned_char,
-                  2: self._parse_unsigned_int,
-                  3: self._parse_unsigned_int,
-                  5: self._parse_unsigned_long,
-                  6: self._parse_double,
-                  8: self._parse_string,
-                  9: self._parse_char_array,
-                  11: self._parse_metadata_item
-                  }
-        return parser[self._datatype]()
-
-    def _parse_unsigned_char(self):
-        self._length = 1
-        return self._unpack("B", self._get_bytes(self._length))
-
-    def _parse_unsigned_int(self):
-        self._length = 4
-        return self._unpack("I", self._get_bytes(self._length))
-
-    def _parse_unsigned_long(self):
-        self._length = 8
-        return self._unpack("Q", self._get_bytes(self._length))
-
-    def _parse_double(self):
-        self._length = 8
-        return self._unpack("d", self._get_bytes(self._length))
-
-    def _parse_string(self):
-        # the string is of unknown length but ends at the first instance of \x00\x00
-        stop = self._body.index("\x00\x00")
-        self._length = stop
-        return self._body[:stop - 1].decode("utf16").encode("utf8")
-
-    def _parse_char_array(self):
-        array_length = self._unpack("Q", self._get_bytes(8))
-        self._length = array_length + 8
-        return array.array("B", self._body[8:array_length])
-
-    def _parse_metadata_item(self):
-        count, length = struct.unpack("<IQ", self._get_bytes(12))
-        metadata_set = MetadataSet(self._body, 0, count)
-
-    def _unpack(self, kind, data):
-        """
-        :param kind:    the datatype to interpret the bytes as (see: https://docs.python.org/2/library/struct.html#struct-format-strings)
-        :type kind:     str
-        :param data:    the bytes to be converted
-        :type data:     bytes
-
-        Parses a sequence of bytes and converts them to a Python data type.
-        struct.unpack() returns a tuple but we only want the first element.
-
-        """
-        return struct.unpack(kind, data)[0]
-
-
-class MetadataSet(object):
-    """
-    A container of metadata items. Can contain other MetadataSet objects.
-
-    """
-    def __init__(self, data, start, item_count):
-        self._items = []
-        self._parse(data, start, item_count)
-
-    def _parse(self, data, start, item_count):
-        for item in range(item_count):
-            metadata_item = MetadataItem(start, data)
-            if not metadata_item.is_valid:
-                break
-            start += metadata_item.length
-
-
-class Chunkmap(object):
-    def __init__(self):
-        pass
-
-    def read(self, filename):
-        with open(filename, "rb") as f:
-            data = f.read(-1)
-        self.parse(data, 1)
-
-    def parse(self, data, count):
-        data = BytesIO(data)
-        res = {}
-        total_count = 0
-        for c in range(count):
-            lastpos = data.tell()
-            total_count += 1
-            hdr = data.read(2)
-            if not hdr:
-                break
-            typ = ord(hdr[0])
-            bname = data.read(2*ord(hdr[1]))
-            name = bname.decode("utf16")[:-1].encode("utf8")
-            if typ == 1:
-                value, = struct.unpack("B", data.read(1))
-            elif typ in [2, 3]:
-                value, = struct.unpack("I", data.read(4))
-            elif typ == 5:
-                value, = struct.unpack("Q", data.read(8))
-            elif typ == 6:
-                value, = struct.unpack("d", data.read(8))
-            elif typ == 8:
-                value = data.read(2)
-                while value[-2:] != "\x00\x00":
-                    value += data.read(2)
-                value = value.decode("utf16")[:-1].encode("utf8")
-            elif typ == 9:
-                cnt, = struct.unpack("Q", data.read(8))
-                value = array.array("B", data.read(cnt))
-            elif typ == 11:
-                curpos = data.tell()
-                newcount, length = struct.unpack("<IQ", data.read(12))
-                curpos = data.tell()
-                length -= data.tell()-lastpos
-                nextdata = data.read(length)
-                value = self.parse(nextdata, newcount)
-                # Skip some offsets
-                data.read(newcount * 8)
-            else:
-                assert 0, "%s hdr %x:%x unknown" % (name, ord(hdr[0]),  ord(hdr[1]))
-            if not name in res:
-                res[name] = value
-            else:
-                if not isinstance(res[name], list):
-                    res[name] = [res[name]]
-                res[name].append(value)
-        x = data.read()
-        assert not x, "skip %d %s" % (len(x), repr(x[:30]))
-        return res
+        skimage.io.show()