DOC: move custom_colormap

jklymak · jklymak · commit f58f5f3fba15 · 2018-08-22T10:57:43.000-07:00
diff --git a/.flake8 b/.flake8
@@ -86,6 +86,7 @@ per-file-ignores =
     tutorials/advanced/transforms_tutorial.py: E402, E501
     tutorials/colors/colormaps.py: E501
     tutorials/colors/colors.py: E402
+    tutorials/colors/colormap-manipulation.py: E402
     tutorials/intermediate/artists.py: E402, E501
     tutorials/intermediate/constrainedlayout_guide.py: E402, E501
     tutorials/intermediate/gridspec.py: E402, E501
@@ -114,6 +115,7 @@ per-file-ignores =
     examples/color/color_demo.py: E402
     examples/color/colorbar_basics.py: E402
     examples/color/colormap_reference.py: E402
+    examples/color/custom_cmap.py: E402
     examples/color/named_colors.py: E402
     examples/event_handling/data_browser.py: E501
     examples/event_handling/path_editor.py: E501
@@ -129,7 +131,6 @@ per-file-ignores =
     examples/images_contours_and_fields/contourf_demo.py: E402, E501
     examples/images_contours_and_fields/contourf_hatching.py: E402
     examples/images_contours_and_fields/contourf_log.py: E402
-    examples/images_contours_and_fields/custom_cmap.py: E402
     examples/images_contours_and_fields/demo_bboximage.py: E402
     examples/images_contours_and_fields/image_clip_path.py: E402
     examples/images_contours_and_fields/image_demo.py: E402
diff --git a/examples/color/custom_cmap.py b/examples/color/custom_cmap.py
@@ -3,6 +3,9 @@
 Creating a colormap from a list of colors
 =========================================
 
+For more detail on creating and manipulating colormaps see
+:doc:`/tutorials/colors/colormap-manipulation`.
+
 Creating a :doc:`colormap </tutorials/colors/colormaps>`
 from a list of colors can be done with the
 :meth:`~.colors.LinearSegmentedColormap.from_list` method of
diff --git a/lib/matplotlib/cm.py b/lib/matplotlib/cm.py
@@ -1,8 +1,13 @@
 """
 Builtin colormaps, colormap handling utilities, and the `ScalarMappable` mixin.
 
-See :doc:`/gallery/color/colormap_reference` for a list of builtin colormaps.
-See :doc:`/tutorials/colors/colormaps` for an in-depth discussion of colormaps.
+  - See :doc:`/gallery/color/colormap_reference` for a list of builtin
+    colormaps.
+  - See :doc:`/tutorials/colors/colormaps` for an in-depth discussion of
+    choosing colormaps.
+  - See :doc:`/tutorials/colors/colormap-manipulation` for an in-depth
+    discussion of how to manipulate colormaps.
+
 """
 
 import functools
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -6,14 +6,25 @@
 
 This module includes functions and classes for color specification
 conversions, and for mapping numbers to colors in a 1-D array of colors called
-a colormap. Colormapping typically involves two steps: a data array is first
-mapped onto the range 0-1 using an instance of :class:`Normalize` or of a
-subclass; then this number in the 0-1 range is mapped to a color using an
-instance of a subclass of :class:`Colormap`.  Two are provided here:
-:class:`LinearSegmentedColormap`, which is used to generate all the built-in
-colormap instances, but is also useful for making custom colormaps, and
-:class:`ListedColormap`, which is used for generating a custom colormap from a
-list of color specifications.
+a colormap.
+
+Mapping data onto colors using a colormap typically involves two steps:
+a data array is first mapped onto the range 0-1 using a subclass of
+:class:`Normalize`, then this number is mapped to a color using
+a subclass of :class:`Colormap`.  Two are provided here:
+:class:`LinearSegmentedColormap`, which uses piecewise-linear interpolation
+to define colormaps, and :class:`ListedColormap`, which makes a colormap
+from a list of colors.
+
+.. seealso::
+
+  :doc:`/tutorials/colors/colormap-manipulation` for examples of how to
+  make colormaps and
+
+  :doc:`/tutorials/colors/colormaps` for a list of built-in colormaps.
+
+  :doc:`/tutorials/colors/colormapnorms` for more details about data
+  normalization
 
 The module also provides functions for checking whether an object can be
 interpreted as a color (:func:`is_color_like`), for converting such an object
diff --git a/tutorials/colors/colormap-manipulation.py b/tutorials/colors/colormap-manipulation.py
@@ -76,16 +76,17 @@
 newcolors[:25, :] = pink
 newcmp = ListedColormap(newcolors)
 
+
 def plot_examples(cms):
     """
     helper function to plot two colormaps
     """
     np.random.seed(19680801)
-    data = np.random.randn(30,30)
+    data = np.random.randn(30, 30)
 
     fig, axs = plt.subplots(1, 2, figsize=(6, 3), constrained_layout=True)
-    for [ax, cm] in zip(axs, cms):
-        psm = ax.pcolormesh(data, cmap=cm, rasterized=True, vmin=-4, vmax=4)
+    for [ax, cmap] in zip(axs, cms):
+        psm = ax.pcolormesh(data, cmap=cmap, rasterized=True, vmin=-4, vmax=4)
         fig.colorbar(psm, ax=ax)
     plt.show()
 
@@ -145,6 +146,7 @@ def plot_examples(cms):
                    [0.5,  0.0, 0.0],
                    [1.0,  1.0, 1.0]]}
 
+
 def plot_linearmap(cdict):
     newcmp = LinearSegmentedColormap('testCmap', segmentdata=cdict, N=256)
     rgba = newcmp(np.linspace(0, 1, 256))
@@ -170,9 +172,9 @@ def plot_linearmap(cdict):
 # are both superfluous to the interpolation, which happens between the last
 # element of the first anchor and the first element of the second anchor.
 
-cdict['red'] =   [[0.0,  0.0, 0.3],
-                  [0.5,  1.0, 0.9],
-                  [1.0,  1.0, 1.0]]
+cdict['red'] = [[0.0,  0.0, 0.3],
+                [0.5,  1.0, 0.9],
+                [1.0,  1.0, 1.0]]
 plot_linearmap(cdict)
 
 
