Merge pull request matplotlib#3978 from mdboom/fix-image-clip-zoom

Fix clipping/zooming of inverted images

Author: pelson

lib/matplotlib/image.py

@@ -186,10 +186,7 @@ def _get_unsampled_image(self, A, image_extents, viewlim):
             iy0 = max(0, int(y0 - self._filterrad))
             y1 = (viewlim.y1-ymin)/dyintv * numrows
             iy1 = min(numrows, int(y1 + self._filterrad))
-            if self.origin == 'upper':
-                yslice = slice(numrows-iy1, numrows-iy0)
-            else:
-                yslice = slice(iy0, iy1)
+            yslice = slice(iy0, iy1)
             ymin_old = ymin
             ymin = ymin_old + iy0*dyintv/numrows
             ymax = ymin_old + iy1*dyintv/numrows

lib/matplotlib/tests/baseline_images/test_image/zoom_and_clip_upper_origin.png

@@ -357,6 +357,20 @@ def test_get_window_extent_for_AxisImage():
     assert_array_equal(im_bbox.get_points(), [[400, 200], [700, 900]])
 
 
+@image_comparison(baseline_images=['zoom_and_clip_upper_origin'],
+                  remove_text=True,
+                  extensions=['png'])
+def test_zoom_and_clip_upper_origin():
+    image = np.arange(100)
+    image = image.reshape((10, 10))
+
+    fig = plt.figure()
+    ax = fig.add_subplot(111)
+    ax.imshow(image)
+    ax.set_ylim(2.0, -0.5)
+    ax.set_xlim(-0.5, 2.0)
+
+
 if __name__=='__main__':
     import nose
     nose.runmodule(argv=['-s','--with-doctest'], exit=False)