Merge pull request yt-project#4792 from chrishavlin/enfornce_dpi_in_s…

…how_mpl

BUG: enforce Figure dpi in _show_mpl

yt/visualization/volume_rendering/scene.py

@@ -526,7 +526,9 @@ def _show_mpl(self, im, sigma_clip=None, dpi=100):
         from matplotlib.figure import Figure
 
         s = im.shape
-        self._render_figure = Figure(figsize=(s[1] / float(dpi), s[0] / float(dpi)))
+        self._render_figure = Figure(
+            figsize=(s[1] / float(dpi), s[0] / float(dpi)), dpi=dpi
+        )
         self._render_figure.clf()
         ax = self._render_figure.add_subplot(111)
         ax.set_position([0, 0, 1, 1])