translator for specreduce Trace objects

CHANGES.rst

@@ -1,9 +1,11 @@
-0.4.1 (unreleased)
+0.5.0 (unreleased)
 ------------------
 
 - Updated ``AstropyRegions`` translator to export ``roi.theta`` angle
   (supported as of ``glue`` 1.5.0). [#73]
 
+- Added support to import and export specreduce Trace objects. [#72]
+
 0.4.0 (2022-04-07)
 ------------------
 

docs/translators.rst

@@ -20,6 +20,9 @@ data classes. At this time, the following data classes are supported:
 * :class:`~astropy.nddata.CCDData` for spectra (from the `astropy.nddata
   <https://docs.astropy.org/en/stable/nddata/>`_ sub-package)
 
+* :class `~specreduce.tracing.Trace` for 2D spectral traces (from the `specreduce
+  <https://specreduce.readthedocs.io>`_ package)
+
 Working with these classes is described in `Datasets and subsets`_ below. In
 addition, this plugin defines ways for glue selections to be translated to
 Astropy `regions <https://astropy-regions.readthedocs.io>`_, as described in

glue_astronomy/translators/__init__.py

@@ -2,3 +2,4 @@
 from . import regions  # noqa
 from . import spectral_cube  # noqa
 from . import spectrum1d  # noqa
+from . import trace # noqa

glue_astronomy/translators/tests/test_trace.py

@@ -0,0 +1,29 @@
+import numpy as np
+
+from specreduce import tracing
+from specreduce.utils.synth_data import make_2dspec_image
+
+from glue.core import Data, DataCollection
+
+
+def test_trace():
+
+    image = make_2dspec_image()
+    trace = tracing.FlatTrace(image, 5)
+
+    data_collection = DataCollection()
+
+    data_collection['dc_trace'] = trace
+    data = data_collection['dc_trace']
+    assert isinstance(data, Data)
+    assert np.all(data['trace'] == trace.trace)
+
+    trace_from_data = data.get_object()
+    assert isinstance(trace_from_data, tracing.FlatTrace)
+
+    # now edit the glue data object, this should now map to an ArrayTrace (instead of a FlatTrace)
+    new_trace = np.ones_like(trace.trace)
+    data.update_components({data.get_component('trace'): new_trace})
+    trace_from_data = data.get_object()
+    assert isinstance(trace_from_data, tracing.ArrayTrace)
+    assert np.all(trace_from_data.trace == new_trace)

glue_astronomy/translators/trace.py

@@ -0,0 +1,48 @@
+import numpy as np
+
+from glue.config import data_translator
+from glue.core import Data, Subset
+
+from specreduce.tracing import Trace, ArrayTrace
+
+
+@data_translator(Trace)
+class TraceHandler:
+
+    def to_data(self, obj):
+        """
+        Convert a specreduce Trace object to a glue Data object
+
+        Parameters
+        ----------
+        obj : `specreduce.tracing.Trace`
+            The Trace object to convert
+        """
+        data = Data(trace=obj.trace)
+        if hasattr(obj, 'meta'):
+            data.meta.update(obj.meta)
+        data.meta['Trace'] = obj
+        return data
+
+    def to_object(self, data, attribute=None):
+        """
+        Convert a glue Data object to a Trace object.
+
+        Parameters
+        ----------
+        data : `glue.core.data.Data`
+            The data to convert to a Trace object
+        attribute : `glue.core.component_id.ComponentID`
+            The attribute to use for the Trace data
+        """
+
+        if isinstance(data, Subset):
+            raise NotImplementedError("Cannot convert subset to Trace object.")
+        if not isinstance(data.meta.get('Trace'), Trace):
+            raise TypeError("data is not a valid specreduce Trace object.")
+
+        trace = data.meta['Trace']
+        if not np.all(trace.trace[1] == data['trace']):
+            trace = ArrayTrace(trace.image, data['trace'])
+
+        return trace

setup.cfg

@@ -21,6 +21,7 @@ install_requires =
     glue-core>=1.0
     regions>=0.4
     specutils>=0.7
+    specreduce>=1.0.0
     spectral-cube>=0.6.0
 
 [options.extras_require]