matplotlib · QuLogic · Sep 17, 2020 · Sep 17, 2020
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -474,8 +474,10 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
                # do not run the vmin/vmax through the same pipeline we can
                # have values close or equal to the boundaries end up on the
                # wrong side.
-                vrange = np.array([self.norm.vmin, self.norm.vmax],
-                                  dtype=scaled_dtype)
+                vmin, vmax = self.norm.vmin, self.norm.vmax
+                if vmin is np.ma.masked:
+                    vmin, vmax = a_min, a_max
+                vrange = np.array([vmin, vmax], dtype=scaled_dtype)

                A_scaled -= a_min
                vrange -= a_min

diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -846,6 +846,14 @@ def test_mask_image():
    ax2.imshow(A, interpolation='nearest')


+def test_mask_image_all():
+    # Test behavior with an image that is entirely masked does not warn
+    data = np.full((2, 2), np.nan)
+    fig, ax = plt.subplots()
+    ax.imshow(data)
+    fig.canvas.draw_idle()  # would emit a warning
+
+
 @image_comparison(['imshow_endianess.png'], remove_text=True)
 def test_imshow_endianess():
    x = np.arange(10)