If we want to save the plot, assume that it is being done headless. (mementum#315)

beejaysea · mementum · commit d20ff2a0c248 · 2017-06-11T08:34:04.000+02:00
diff --git a/backtrader/cerebro.py b/backtrader/cerebro.py
@@ -924,7 +924,7 @@ 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)
+                                    start=start, end=end, savefig=savefig)
                 # pfillers=pfillers2)
 
                 figs.append(rfig)
diff --git a/backtrader/plot/plot.py b/backtrader/plot/plot.py
@@ -114,14 +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, **kwargs):
+             start=None, end=None, savefig=False, **kwargs):
         # pfillers={}):
         if not strategy.datas:
             return
 
         if not len(strategy):
             return
 
+        if savefig:
+            matplotlib.use('agg')
+
         if iplot:
             if 'ipykernel' in sys.modules:
                 matplotlib.use('nbagg')
