Remove unused keywords and allow frame instances to be used for ``get…

…_transform``

wcsaxes/core.py

@@ -177,7 +177,7 @@ def get_xlabel(self):
     def get_ylabel(self):
         return self.coords[self._y_index].get_axislabel()
 
-    def get_coords_overlay(self, frame, equinox=None, obstime=None, coord_meta=None):
+    def get_coords_overlay(self, frame, coord_meta=None):
 
         # Here we can't use get_transform because that deals with
         # pixel-to-pixel transformations when passing a WCS object.
@@ -186,7 +186,7 @@ def get_coords_overlay(self, frame, equinox=None, obstime=None, coord_meta=None)
         else:
             if coord_meta is None:
                 coord_meta = get_coord_meta(frame)
-            transform = self._get_transform_no_transdata(frame, equinox=equinox, obstime=obstime)
+            transform = self._get_transform_no_transdata(frame)
             coords = CoordinatesMap(self, transform=transform, coord_meta=coord_meta, frame_class=self.frame_class)
 
         self._all_coords.append(coords)
@@ -201,7 +201,7 @@ def get_coords_overlay(self, frame, equinox=None, obstime=None, coord_meta=None)
 
         return coords
 
-    def get_transform(self, frame, equinox=None, obstime=None):
+    def get_transform(self, frame):
         """
         Return a transform from the specified frame to display coordinates.
 
@@ -230,10 +230,11 @@ def get_transform(self, frame, equinox=None, obstime=None):
                   ``WCSAxes`` instance).
                 * ``'fk5'`` or ``'galactic'``: return a transformation from
                   the specified frame to the pixel/data coordinates.
+                * :class:`~astropy.coordinates.BaseCoordinateFrame` instance.
         """
-        return self._get_transform_no_transdata(frame, equinox=equinox, obstime=obstime).inverted() + self.transData
+        return self._get_transform_no_transdata(frame).inverted() + self.transData
 
-    def _get_transform_no_transdata(self, frame, equinox=None, obstime=None):
+    def _get_transform_no_transdata(self, frame):
         """
         Return a transform from data to the specified frame
         """

wcsaxes/tests/test_display_world_coordinates.py

@@ -6,6 +6,8 @@
 from astropy.wcs import WCS
 from astropy.extern import six
 from astropy.tests.helper import pytest
+from astropy.coordinates import FK5
+from astropy.time import Time
 
 from .test_images import BaseImageTests
 
@@ -58,6 +60,40 @@ def test_overlay_coords(self, tmpdir):
 
         assert string_world3 == six.u('267.176 -28\xb045\'56" (world, overlay 1)')
 
+        overlay = ax.get_coords_overlay(FK5())
+
+        # Regression test for bug that caused format to always be taken from
+        # main world coordinates.
+        overlay[0].set_major_formatter('d.ddd')
+
+        # On some systems, fig.canvas.draw is not enough to force a draw, so we
+        # save to a temporary file.
+        fig.savefig(tmpdir.join('test3.png').strpath)
+
+        event5 = KeyEvent('test_pixel_coords', canvas, 'w')
+        fig.canvas.key_press_event(event4.key, guiEvent=event4)
+        # Test that it displays the overlay world coordinates
+        string_world4 = ax._display_world_coords(0.523412, 0.518311)
+
+        assert string_world4 == six.u('267.176 -28\xb045\'56" (world, overlay 2)')
+
+        overlay = ax.get_coords_overlay(FK5(equinox=Time("J2030")))
+
+        # Regression test for bug that caused format to always be taken from
+        # main world coordinates.
+        overlay[0].set_major_formatter('d.ddd')
+
+        # On some systems, fig.canvas.draw is not enough to force a draw, so we
+        # save to a temporary file.
+        fig.savefig(tmpdir.join('test4.png').strpath)
+
+        event6 = KeyEvent('test_pixel_coords', canvas, 'w')
+        fig.canvas.key_press_event(event5.key, guiEvent=event4)
+        # Test that it displays the overlay world coordinates
+        string_world5 = ax._display_world_coords(0.523412, 0.518311)
+
+        assert string_world5 == six.u('267.652 -28\xb046\'23" (world, overlay 3)')
+
     def test_cube_coords(self, tmpdir):
         wcs = WCS(self.cube_header)
 

wcsaxes/transforms.py

@@ -16,7 +16,9 @@
 from astropy.wcs import WCS
 from astropy.extern import six
 from astropy.coordinates import (SkyCoord, frame_transform_graph,
-                                 SphericalRepresentation, UnitSphericalRepresentation)
+                                 SphericalRepresentation,
+                                 UnitSphericalRepresentation,
+                                 BaseCoordinateFrame)
 
 from .wcs_utils import wcs_to_celestial_frame
 
@@ -173,6 +175,7 @@ def inverted(self):
 
 
 class CoordinateTransform(CurvedTransform):
+
     def __init__(self, input_system, output_system):
         super(CoordinateTransform, self).__init__()
         self._input_system_name = input_system
@@ -184,13 +187,21 @@ def __init__(self, input_system, output_system):
             self.input_system = frame_transform_graph.lookup_name(self._input_system_name)
             if self.input_system is None:
                 raise ValueError("Frame {0} not found".format(self._input_system_name))
+        elif isinstance(self._input_system_name, BaseCoordinateFrame):
+            self.input_system = self._input_system_name
+        else:
+            raise TypeError("input_system should be a WCS instance, string, or a coordinate frame instance")
 
         if isinstance(self._output_system_name, WCS):
             self.output_system = wcs_to_celestial_frame(self._output_system_name)
         elif isinstance(self._output_system_name, six.string_types):
             self.output_system = frame_transform_graph.lookup_name(self._output_system_name)
             if self.output_system is None:
                 raise ValueError("Frame {0} not found".format(self._output_system_name))
+        elif isinstance(self._output_system_name, BaseCoordinateFrame):
+            self.output_system = self._output_system_name
+        else:
+            raise TypeError("output_system should be a WCS instance, string, or a coordinate frame instance")
 
         if self.output_system == self.input_system:
             self.same_frames = True

wcsaxes/utils.py

@@ -3,6 +3,7 @@
 
 from astropy import units as u
 from astropy.extern import six
+from astropy.coordinates import BaseCoordinateFrame
 
 # Modified from axis_artist, supports astropy.units
 
@@ -107,7 +108,10 @@ def get_coord_meta(frame):
         if isinstance(frame, six.string_types):
             frame = frame_transform_graph.lookup_name(frame)
 
-        names = list(frame().representation_component_names.keys())
+        if not isinstance(frame, BaseCoordinateFrame):
+            frame = frame()
+
+        names = list(frame.representation_component_names.keys())
         coord_meta['name'] = names[:2]
 
     except ImportError: