Update imshow_all

Passing unkown kwargs such as shape to imshow seems to raise an error
with more recent versions of matplotlib. A good opportunity, to
provide and docuemnt the keyword parameters in a more explicit way.

Note I'm not to sure on the strange calculation of width for the
figsize. The width gets smaller the more rows there are and multplied
with 0.75 but only for more than one rows?

Author: lagru

lectures/3_morphological_operations.ipynb

@@ -86,7 +86,7 @@
    "metadata": {},
    "outputs": [],
    "source": [
-    "skdemo.imshow_all(image, morphology.erosion(image, sq), shape=(1, 2))"
+    "skdemo.imshow_all(image, morphology.erosion(image, sq))"
    ]
   },
   {

lectures/skdemo/_skdemo.py

@@ -42,30 +42,39 @@ def imshow_rgb_shifted(rgb_image, shift=100, ax=None):
     ax.set_axis_off()
 
 
-def imshow_all(*images, **kwargs):
+def imshow_all(
+    *images, limits='image', titles=None, shape=None, size=5, **kwargs
+):
     """ Plot a series of images side-by-side.
 
     Convert all images to float so that images have a common intensity range.
 
     Parameters
     ----------
-    limits : str
+    images : tuple
+        The images to plot.
+    limits : 'image' or 'dtype', optional
         Control the intensity limits. By default, 'image' is used set the
         min/max intensities to the min/max of all images. Setting `limits` to
         'dtype' can also be used if you want to preserve the image exposure.
     titles : list of str
         Titles for subplots. If the length of titles is less than the number
         of images, empty strings are appended.
+    shape : tuple, optional
+        A two-element tuple that defines the shape of the subfigure grid as
+        (rows, columns). If not given, all `ìmages` are shown in a single row.
+    size : int, optional
+        Width and height of each subplot in inches.
     kwargs : dict
         Additional keyword-arguments passed to `imshow`.
     """
     images = [img_as_float(img) for img in images]
 
-    titles = kwargs.pop('titles', [])
+    if titles is None:
+        titles = []
     if len(titles) != len(images):
         titles = list(titles) + [''] * (len(images) - len(titles))
 
-    limits = kwargs.pop('limits', 'image')
     if limits == 'image':
         kwargs.setdefault('vmin', min(img.min() for img in images))
         kwargs.setdefault('vmax', max(img.max() for img in images))
@@ -74,13 +83,13 @@ def imshow_all(*images, **kwargs):
         kwargs.setdefault('vmin', vmin)
         kwargs.setdefault('vmax', vmax)
 
-    nrows, ncols = kwargs.get('shape', (1, len(images)))
+    if shape is None:
+        shape = (1, len(images))
+    nrows, ncols = shape
 
-    size = nrows * kwargs.pop('size', 5)
-    width = size * len(images)
-    if nrows > 1:
-        width /= nrows * 1.33
-    fig, axes = plt.subplots(nrows=nrows, ncols=ncols, figsize=(width, size))
+    height = nrows * size
+    width = ncols * size
+    fig, axes = plt.subplots(nrows=nrows, ncols=ncols, figsize=(width, height))
     for ax, img, label in zip(axes.ravel(), images, titles):
         ax.imshow(img, **kwargs)
         ax.set_title(label)