Merge pull request #8006 from tacaswell/fix_imshow_segfault

QuLogic · web-flow · commit 013fd3f185fe · 2017-02-06T17:18:58.000-05:00
FIX: do not try to render empty images
diff --git a/lib/matplotlib/image.py b/lib/matplotlib/image.py
@@ -301,6 +301,10 @@ def _make_image(self, A, in_bbox, out_bbox, clip_bbox, magnification=1.0,
         if A is None:
             raise RuntimeError('You must first set the image'
                                ' array or the image attribute')
+        if any(s == 0 for s in A.shape):
+            raise RuntimeError("_make_image must get a non-empty image. "
+                               "Your Artist's draw method must filter before "
+                               "this method is called.")
 
         clipped_bbox = Bbox.intersection(out_bbox, clip_bbox)
 
@@ -478,9 +482,17 @@ def _check_unsampled_image(self, renderer):
 
     @allow_rasterization
     def draw(self, renderer, *args, **kwargs):
+        # if not visible, declare victory and return
         if not self.get_visible():
+            self.stale = False
             return
 
+        # for empty images, there is nothing to draw!
+        if self.get_array().size == 0:
+            self.stale = False
+            return
+
+        # actually render the image.
         gc = renderer.new_gc()
         self._set_gc_clip(gc)
         gc.set_alpha(self.get_alpha())
diff --git a/lib/matplotlib/tests/test_image.py b/lib/matplotlib/tests/test_image.py
@@ -32,6 +32,7 @@
 import numpy as np
 
 import nose
+import nose.tools
 
 try:
     from PIL import Image
@@ -765,5 +766,15 @@ def test_imshow_no_warn_invalid():
     assert len(warns) == 0
 
 
+@cleanup
+def test_empty_imshow():
+    fig, ax = plt.subplots()
+    im = ax.imshow([[]])
+    im.set_extent([-5, 5, -5, 5])
+    fig.canvas.draw()
+
+    nose.tools.assert_raises(RuntimeError, im.make_image, fig._cachedRenderer)
+
+
 if __name__ == '__main__':
     nose.runmodule(argv=['-s', '--with-doctest'], exit=False)
