Fix complex_data for readonly daq

src/python_spectrometer/_plot_manager.py

@@ -32,7 +32,7 @@ class PlotManager:
                  plot_cumulative_normalized: bool = False, plot_style: _styleT = 'fast',
                  plot_update_mode: str = 'never', plot_dB_scale: bool = False, prop_cycle=None,
                  raw_unit: str = 'V', processed_unit: Optional[str] = None,
-                 uses_windowed_estimator: bool = True, complex_data: bool = False,
+                 uses_windowed_estimator: bool = True, complex_data: Optional[bool] = False,
                  figure_kw: Optional[Mapping] = None, subplot_kw: Optional[Mapping] = None,
                  gridspec_kw: Optional[Mapping] = None, legend_kw: Optional[Mapping] = None):
         """A helper class that manages plotting spectrometer data."""
@@ -58,7 +58,7 @@ class PlotManager:
         self.prop_cycle = prop_cycle or plt.rcParams['axes.prop_cycle']
         self.raw_unit = raw_unit
         self.uses_windowed_estimator = uses_windowed_estimator
-        self.complex_data = complex_data
+        self._complex_data = complex_data
 
         self._leg = None
         self.axes = {key: dict.fromkeys(self.LINE_TYPES) for key in self.PLOT_TYPES}
@@ -323,6 +323,20 @@ class PlotManager:
             if 'fig' in self.__dict__:
                 self.setup_figure()
 
+    @property
+    def complex_data(self) -> bool:
+        """Is there complex data resulting in negative frequencies in the FFT?"""
+        if self._complex_data is not None:
+            return self._complex_data
+
+        complex_raw_data = any(np.iscomplexobj(d['timetrace_raw'])
+                               for d in self._data.values()
+                               if 'timetrace_raw' in d)
+        complex_processed_data = any(np.iscomplexobj(d['timetrace_processed'])
+                                     for d in self._data.values()
+                                     if 'timetrace_processed' in d)
+        return complex_raw_data or complex_processed_data
+
     def main_plot(self, key, line_type):
         x, y = self.get_freq_data(key, line_type, self.plot_dB_scale)
 

src/python_spectrometer/core.py

@@ -411,8 +411,13 @@ class Spectrometer:
             self.psd_estimator = partial(welch, **psd_estimator)
         else:
             raise TypeError('psd_estimator should be callable or kwarg dict for welch().')
+
         uses_windowed_estimator = 'window' in inspect.signature(self.psd_estimator).parameters
+
+        if self.daq is not None:
             complex_data = np.issubdtype(self.daq.DTYPE, np.complexfloating)
+        else:
+            complex_data = None
 
         self._plot_manager = PlotManager(self._data, plot_raw, plot_timetrace,
                                          plot_cumulative, plot_negative_frequencies,