Merge pull request #1817 from blink1073/upgrade-imshow

ENH: Allow axes to be provided to imshow and fix colorbar

.travis.yml

@@ -18,8 +18,8 @@ addons:
     packages:
     - ccache
     - libfreeimage3
-    - texlive 
-    - texlive-latex-extra 
+    - texlive
+    - texlive-latex-extra
     - dvipng
     - python-qt4
 env:

skimage/io/_plugins/matplotlib_plugin.py

@@ -1,6 +1,7 @@
 from collections import namedtuple
 import numpy as np
 import matplotlib.pyplot as plt
+from mpl_toolkits.axes_grid1 import make_axes_locatable
 from ...util import dtype as dtypes
 from ...exposure import is_low_contrast
 from ...util.colormap import viridis
@@ -110,7 +111,7 @@ def _get_display_range(image):
     return lo, hi, cmap
 
 
-def imshow(im, *args, **kwargs):
+def imshow(im, ax=None, show_cbar=None, **kwargs):
     """Show the input image and return the current axes.
 
     By default, the image is displayed in greyscale, rather than
@@ -131,8 +132,11 @@ def imshow(im, *args, **kwargs):
     ----------
     im : array, shape (M, N[, 3])
         The image to display.
-
-    *args, **kwargs : positional and keyword arguments
+    ax: `matplotlib.axes.Axes`, optional
+        The axis to use for the image, defaults to plt.gca().
+    show_cbar: boolean, optional.
+        Whether to show the colorbar (used to override default behavior).
+    **kwargs : Keyword arguments
         These are passed directly to `matplotlib.pyplot.imshow`.
 
     Returns
@@ -147,9 +151,15 @@ def imshow(im, *args, **kwargs):
     kwargs.setdefault('cmap', cmap)
     kwargs.setdefault('vmin', lo)
     kwargs.setdefault('vmax', hi)
-    ax_im = plt.imshow(im, *args, **kwargs)
-    if cmap != _default_colormap:
-        plt.colorbar()
+
+    ax = ax or plt.gca()
+    ax_im = ax.imshow(im, **kwargs)
+    if (cmap != _default_colormap and show_cbar is not False) or show_cbar:
+        divider = make_axes_locatable(ax)
+        cax = divider.append_axes("right", size="5%", pad=0.05)
+        plt.colorbar(ax_im, cax=cax)
+    ax.set_adjustable('box-forced')
+    ax.get_figure().tight_layout()
     return ax_im
 
 imread = plt.imread

skimage/io/tests/test_mpl_imshow.py

@@ -78,7 +78,11 @@ def test_low_dynamic_range():
 
 def test_outside_standard_range():
     plt.figure()
-    with expected_warnings(["out of standard range"]):
+    # Warning raised by matplotlib on Windows:
+    # "The CObject type is marked Pending Deprecation in Python 2.7.
+    #  Please use capsule objects instead."
+    # Ref: https://docs.python.org/2/c-api/cobject.html
+    with expected_warnings(["out of standard range|CObject type is marked"]):
         ax_im = io.imshow(im_hi)
     assert ax_im.get_clim() == (im_hi.min(), im_hi.max())
     assert n_subplots(ax_im) == 2
@@ -87,7 +91,11 @@ def test_outside_standard_range():
 
 def test_nonstandard_type():
     plt.figure()
-    with expected_warnings(["Low image dynamic range"]):
+    # Warning raised by matplotlib on Windows:
+    # "The CObject type is marked Pending Deprecation in Python 2.7.
+    #  Please use capsule objects instead."
+    # Ref: https://docs.python.org/2/c-api/cobject.html
+    with expected_warnings(["Low image dynamic range|CObject type is marked"]):
         ax_im = io.imshow(im64)
     assert ax_im.get_clim() == (im64.min(), im64.max())
     assert n_subplots(ax_im) == 2