SF.net SVN: matplotlib: [4930] trunk/matplotlib

[<ef...@us...>]

Revision: 4930
          http://matplotlib.svn.sourceforge.net/matplotlib/?rev=4930&view=rev
Author:   efiring
Date:     2008-02-01 23:53:03 -0800 (Fri, 01 Feb 2008)

Log Message:
-----------
Added BoundaryNorm to support irregular discrete color intervals

Modified Paths:
--------------
    trunk/matplotlib/examples/colorbar_only.py
    trunk/matplotlib/lib/matplotlib/colorbar.py
    trunk/matplotlib/lib/matplotlib/colors.py

Modified: trunk/matplotlib/examples/colorbar_only.py
===================================================================
--- trunk/matplotlib/examples/colorbar_only.py	2008-02-01 20:15:59 UTC (rev 4929)
+++ trunk/matplotlib/examples/colorbar_only.py	2008-02-02 07:53:03 UTC (rev 4930)
@@ -2,12 +2,12 @@
 Make a colorbar as a separate figure.
 '''
 
-import pylab
-import matplotlib as mpl
+from matplotlib import pyplot, mpl
 
 # Make a figure and axes with dimensions as desired.
-fig = pylab.figure(figsize=(8,1.5))
-ax = fig.add_axes([0.05, 0.4, 0.9, 0.5])
+fig = pyplot.figure(figsize=(8,3))
+ax1 = fig.add_axes([0.05, 0.65, 0.9, 0.15])
+ax2 = fig.add_axes([0.05, 0.25, 0.9, 0.15])
 
 # Set the colormap and norm to correspond to the data for which
 # the colorbar will be used.
@@ -19,10 +19,33 @@
 # standalone colorbar.  There are many more kwargs, but the
 # following gives a basic continuous colorbar with ticks
 # and labels.
-cb = mpl.colorbar.ColorbarBase(ax, cmap=cmap,
+cb1 = mpl.colorbar.ColorbarBase(ax1, cmap=cmap,
                                    norm=norm,
                                    orientation='horizontal')
-cb.set_label('Some Units')
+cb1.set_label('Some Units')
 
-pylab.show()
+# The second example illustrates the use of a ListedColormap, a
+# BoundaryNorm, and extended ends to show the "over" and "under"
+# value colors.
+cmap = mpl.colors.ListedColormap(['r', 'g', 'b', 'c'])
+cmap.set_over('0.25')
+cmap.set_under('0.75')
 
+# If a ListedColormap is used, the length of the bounds array must be
+# one greater than the length of the color list.  The bounds must be
+# monotonically increasing.
+bounds = [1, 2, 4, 7, 8]
+norm = mpl.colors.BoundaryNorm(bounds)
+cb2 = mpl.colorbar.ColorbarBase(ax2, cmap=cmap,
+                                     norm=norm,
+                                     # to use 'extend', you must
+                                     # specify two extra boundaries:
+                                     boundaries=[0]+bounds+[13],
+                                     extend='both',
+                                     ticks=bounds, # optional
+                                     spacing='proportional',
+                                     orientation='horizontal')
+cb2.set_label('Discrete intervals, some other units')
+
+pyplot.show()
+

Modified: trunk/matplotlib/lib/matplotlib/colorbar.py
===================================================================
--- trunk/matplotlib/lib/matplotlib/colorbar.py	2008-02-01 20:15:59 UTC (rev 4929)
+++ trunk/matplotlib/lib/matplotlib/colorbar.py	2008-02-02 07:53:03 UTC (rev 4930)
@@ -356,7 +356,7 @@
         if b is None:
             b = self.boundaries
         if b is not None:
-            self._boundaries = npy.array(b)
+            self._boundaries = npy.asarray(b, dtype=float)
             if self.values is None:
                 self._values = 0.5*(self._boundaries[:-1]
                                         + self._boundaries[1:])
@@ -456,7 +456,12 @@
         Return colorbar data coordinates for the boundaries of
         a proportional colorbar.
         '''
-        y = self.norm(self._boundaries.copy())
+        if isinstance(self.norm, colors.BoundaryNorm):
+            b = self._boundaries[self._inside]
+            y = (self._boundaries - self._boundaries[0])
+            y = y / (self._boundaries[-1] - self._boundaries[0])
+        else:
+            y = self.norm(self._boundaries.copy())
         if self.extend in ('both', 'min'):
             y[0] = -0.05
         if self.extend in ('both', 'max'):
@@ -492,7 +497,7 @@
         within range, together with their corresponding colorbar
         data coordinates.
         '''
-        if isinstance(self.norm, colors.NoNorm):
+        if isinstance(self.norm, (colors.NoNorm, colors.BoundaryNorm)):
             b = self._boundaries
             xn = x
             xout = x

Modified: trunk/matplotlib/lib/matplotlib/colors.py
===================================================================
--- trunk/matplotlib/lib/matplotlib/colors.py	2008-02-01 20:15:59 UTC (rev 4929)
+++ trunk/matplotlib/lib/matplotlib/colors.py	2008-02-02 07:53:03 UTC (rev 4930)
@@ -684,7 +684,37 @@
         else:
             return vmin * pow((vmax/vmin), value)
 
+class BoundaryNorm(Normalize):
+    def __init__(self, boundaries, clip=False):
+        self.clip = clip
+        self.vmin = boundaries[0]
+        self.vmax = boundaries[-1]
+        self.boundaries = npy.asarray(boundaries)
+        self.midpoints = 0.5 *(self.boundaries[:-1] + self.boundaries[1:])
+        self.N = len(self.boundaries)
 
+    def __call__(self, x, clip=None):
+        if clip is None:
+            clip = self.clip
+        x = ma.asarray(x)
+        mask = ma.getmaskarray(x)
+        xx = x.filled(self.vmax+1)
+        if clip:
+            npy.clip(xx, self.vmin, self.vmax)
+        iret = npy.zeros(x.shape, dtype=npy.int16)
+        for i, b in enumerate(self.boundaries):
+            iret[xx>=b] = i
+        iret[xx<self.vmin] = -1
+        iret[xx>=self.vmax] = self.N
+        ret = ma.array(iret / float(self.N-1), mask=mask)
+        if ret.shape == () and not mask:
+            ret = float(ret)  # assume python scalar
+        return ret
+
+    def inverse(self, value):
+        return self.midpoints[int(value*(self.N-1))]
+
+
 class NoNorm(Normalize):
     '''
     Dummy replacement for Normalize, for the case where we


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