Upgrade matplotlib and for plot-file-logger set agg as backend

requirements.txt

@@ -1,7 +1,7 @@
 colorlover>=0.2.1
 Flask>=0.12.2
 graphviz>=0.8.4
-matplotlib>=2.2.2
+matplotlib>=3.3.2
 numpy>=1.14.5
 seaborn>=0.8.1
 scipy>=0.19.1

trixi/logger/file/numpyplotfilelogger.py

@@ -17,17 +17,22 @@ class NumpyPlotFileLogger(NumpySeabornPlotLogger):
 
     """
 
-    def __init__(self, img_dir, plot_dir, **kwargs):
+    def __init__(self, img_dir, plot_dir, switch_backend=True, **kwargs):
         """
         Initializes a numpy plot file logger to plot images and plots into an image and plot directory
 
         Args:
             img_dir: The directory to store images in
             plot_dir: The directory to store plots in
+            switch_backend: If true switchtes backend to agg
         """
         super(NumpyPlotFileLogger, self).__init__(**kwargs)
         self.img_dir = img_dir
         self.plot_dir = plot_dir
+        if switch_backend:
+            import matplotlib.pyplot as plt
+
+            plt.switch_backend("Agg")
 
     @convert_params
     def show_image(self, image, name, file_format=".png", *args, **kwargs):
@@ -66,7 +71,7 @@ def show_value(self, value, name, counter=None, tag=None, file_format=".png", *a
         else:
             outname = os.path.join(self.plot_dir, tag) + file_format
         os.makedirs(os.path.dirname(outname), exist_ok=True)
-        threaded(savefig_and_close)(figure, outname)
+        savefig_and_close(figure, outname)
 
     @convert_params
     def show_barplot(self, array, name, file_format=".png", *args, **kwargs):

trixi/logger/plt/numpyseabornplotlogger.py

@@ -144,9 +144,9 @@ def show_boxplot(self, array, name, show=True, *args, **kwargs):
 
         handles, _ = ax.get_legend_handles_labels()
         try:
-            legend = kwargs['opts']['legend']
+            legend = kwargs["opts"]["legend"]
             ax.legend(handles, legend)
-        except KeyError: # if no legend is defined
+        except KeyError:  # if no legend is defined
             pass
         if show:
             plt.show(block=False)
@@ -202,8 +202,10 @@ def show_scatterplot(self, array, name=None, show=True, *args, **kwargs):
         """
 
         if not isinstance(array, np.ndarray):
-            raise TypeError("Array must be numpy arrays (this class is called NUMPY seaborn logger, and seaborn"
-                            " can only handle numpy arrays -.- .__. )")
+            raise TypeError(
+                "Array must be numpy arrays (this class is called NUMPY seaborn logger, and seaborn"
+                " can only handle numpy arrays -.- .__. )"
+            )
         if len(array.shape) != 2:
             raise ValueError("Array must be 2D for scatterplot")
         if array.shape[1] != 2: