Allow specification of the matplotlib backend with the parameter use

mementum · mementum · commit 69bdfb7bdd71 · 2017-06-11T08:39:18.000+02:00
diff --git a/backtrader/cerebro.py b/backtrader/cerebro.py
@@ -866,7 +866,7 @@ def getbroker(self):
 
     def plot(self, plotter=None, numfigs=1, iplot=True, start=None, end=None,
              savefig=False, figfilename='backtrader-plot-{j}-{i}.png',
-             width=16, height=9, dpi=300, tight=True,
+             width=16, height=9, dpi=300, tight=True, use=None,
              **kwargs):
         '''
         Plots the strategies inside cerebro
@@ -880,6 +880,9 @@ def plot(self, plotter=None, numfigs=1, iplot=True, start=None, end=None,
         ``iplot``: if ``True`` and running in a ``notebook`` the charts will be
         displayed inline
 
+        ``use``: set it to the name of the desired matplotlib backend. It will
+        take precedence over ``iplot``
+
         ``start``: An index to the datetime line array of the strategy or a
         ``datetime.date``, ``datetime.datetime`` instance indicating the start
         of the plot
@@ -924,7 +927,7 @@ def plot(self, plotter=None, numfigs=1, iplot=True, start=None, end=None,
             for si, strat in enumerate(stratlist):
                 rfig = plotter.plot(strat, figid=si * 100,
                                     numfigs=numfigs, iplot=iplot,
-                                    start=start, end=end, savefig=savefig)
+                                    start=start, end=end, use=use)
                 # pfillers=pfillers2)
 
                 figs.append(rfig)
diff --git a/backtrader/plot/plot.py b/backtrader/plot/plot.py
@@ -114,18 +114,17 @@ def drawtag(self, ax, x, y, facecolor, edgecolor, alpha=0.9, **kwargs):
                       **kwargs)
 
     def plot(self, strategy, figid=0, numfigs=1, iplot=True,
-             start=None, end=None, savefig=False, **kwargs):
+             start=None, end=None, use=None, **kwargs):
         # pfillers={}):
         if not strategy.datas:
             return
 
         if not len(strategy):
             return
 
-        if savefig:
-            matplotlib.use('agg')
-
-        if iplot:
+        if use is not None:
+            matplotlib.use(use)
+        elif iplot:
             if 'ipykernel' in sys.modules:
                 matplotlib.use('nbagg')
 
