From b4dae46be1abb4ce2caf79d4df7de0a50fffc70b Mon Sep 17 00:00:00 2001
From: Frederik Rietdijk <fridh@fridh.nl>
Date: Wed, 22 Jun 2016 16:14:47 +0200
Subject: [PATCH] Signal.spectrogram now returns values

and Signal.plot_spectrogram plots it.
---
 acoustics/_signal.pyx | 22 ++++++++++++++++++++++
 tests/test__signal.py |  8 +++++---
 2 files changed, 27 insertions(+), 3 deletions(-)

diff --git a/acoustics/_signal.pyx b/acoustics/_signal.pyx
index 3465bb08..96524439 100644
--- a/acoustics/_signal.pyx
+++ b/acoustics/_signal.pyx
@@ -622,6 +622,27 @@ class Signal(numpy.ndarray):
 
 
     def spectrogram(self, **kwargs):
+        """Spectrogram of signal.
+
+        :returns: Spectrogram.
+
+        See :func:`scipy.signal.spectrogram`. Some of the default values have been changed.
+        The generated spectrogram consists by default of complex values.
+
+        """
+        params = {
+            'nfft' : 4096,
+            'noverlap' : 128,
+            'mode' : 'complex',
+            }
+        params.update(kwargs)
+
+        t, s, P = spectrogram(self, fs=self.fs, **params)
+
+        return t, s, P
+
+
+    def plot_spectrogram(self, **kwargs):
         """
         Plot spectrogram of the signal.
 
@@ -633,6 +654,7 @@ class Signal(numpy.ndarray):
         .. note:: This method only works for a single channel.
 
         """
+        # To do, use :meth:`spectrogram`.
         params = {
             'xlim' : None,
             'ylim' : None,
diff --git a/tests/test__signal.py b/tests/test__signal.py
index 0716279d..30b0adca 100644
--- a/tests/test__signal.py
+++ b/tests/test__signal.py
@@ -290,16 +290,18 @@ def test_plot_power_spectrum(self, signal):
     def test_plot_phase_spectrum(self, signal):
         signal.plot_phase_spectrum()
     
-    def test_spectrogram(self, signal):
+    def test_plot_spectrogram(self, signal):
         if signal.channels > 1:
             with pytest.raises(ValueError):
-                signal.spectrogram()
+                signal.plot_spectrogram()
         else:
             try:
-                signal.spectrogram()
+                signal.plot_spectrogram()
             except NotImplementedError: # easy way to skip mpl 1.3.1 specgram mode issue
                 pass
         
+    def spectrogram(self, signal):
+        signal.spectrogram()
     
     def test_pickling(self, signal):
         import pickle