Merged matplotlib#819: dmcdougall's stackplot

Author: pelson

CHANGELOG

@@ -41,6 +41,9 @@
            the linear portion relative to the logarithmic portion to be
            adjusted. - MGD
 
+2012-04-14 Added new plot style: stackplot. This new feature supports stacked
+           area plots. - Damon McDougall
+
 2012-04-06 When path clipping changes a LINETO to a MOVETO, it also
            changes any CLOSEPOLY command to a LINETO to the initial
            point. This fixes a problem with pdf and svg where the

boilerplate.py

@@ -69,7 +69,6 @@ def %(func)s(%(argspec)s):
     return %(ret)s
 """
 
-
 # Used for colormap functions
 CMAP_TEMPLATE = AUTOGEN_MSG + """
 def {name}():
@@ -131,6 +130,7 @@ def boilerplate_gen():
         'semilogy',
         'specgram',
         #'spy',
+        'stackplot',
         'stem',
         'step',
         'streamplot',

examples/pylab_examples/stackplot_demo.py

@@ -0,0 +1,18 @@
+import numpy as np
+from matplotlib import pyplot as plt
+
+fnx = lambda : np.random.randint(5, 50, 10)
+y = np.row_stack((fnx(), fnx(), fnx()))
+x = np.arange(10)
+
+y1, y2, y3 = fnx(), fnx(), fnx()
+
+fig = plt.figure()
+ax = fig.add_subplot(111)
+ax.stackplot(x, y)
+plt.show()
+
+fig = plt.figure()
+ax = fig.add_subplot(111)
+ax.stackplot(x, y1, y2, y3)
+plt.show()

lib/matplotlib/axes.py

@@ -29,6 +29,7 @@
 import matplotlib.spines as mspines
 import matplotlib.quiver as mquiver
 import matplotlib.scale as mscale
+import matplotlib.stackplot as mstack
 import matplotlib.streamplot as mstream
 import matplotlib.table as mtable
 import matplotlib.text as mtext
@@ -6410,6 +6411,10 @@ def quiver(self, *args, **kw):
         return q
     quiver.__doc__ = mquiver.Quiver.quiver_doc
 
+    def stackplot(self, x, *args, **kwargs):
+        return mstack.stackplot(self, x, *args, **kwargs)
+    stackplot.__doc__ = mstack.stackplot.__doc__
+
     def streamplot(self, x, y, u, v, density=1, linewidth=None, color=None,
                    cmap=None, norm=None, arrowsize=1, arrowstyle='-|>',
                    minlength=0.1):

lib/matplotlib/pyplot.py

@@ -1636,6 +1636,7 @@ def plotting():
                     until they have been closed; in interactive mode,
                     show generally has no effect.
     specgram        a spectrogram plot
+    stackplot       make a stacked plot
     stem            make a stem plot
     subplot         make a subplot (numrows, numcols, axesnum)
     table           add a table to the axes
@@ -2978,6 +2979,24 @@ def specgram(x, NFFT=256, Fs=2, Fc=0, detrend=mlab.detrend_none,
     sci(ret[-1])
     return ret
 
+# This function was autogenerated by boilerplate.py.  Do not edit as
+# changes will be lost
+@autogen_docstring(Axes.stackplot)
+def stackplot(x, *args, **kwargs):
+    ax = gca()
+    # allow callers to override the hold state by passing hold=True|False
+    washold = ax.ishold()
+    hold = kwargs.pop('hold', None)
+    if hold is not None:
+        ax.hold(hold)
+    try:
+        ret = ax.stackplot(x, *args, **kwargs)
+        draw_if_interactive()
+    finally:
+        ax.hold(washold)
+
+    return ret
+
 # This function was autogenerated by boilerplate.py.  Do not edit as
 # changes will be lost
 @autogen_docstring(Axes.stem)

lib/matplotlib/stackplot.py

@@ -0,0 +1,60 @@
+"""
+Stacked area plot for 1D arrays inspired by Douglas Y'barbo's stackoverflow
+answer:
+http://stackoverflow.com/questions/2225995/how-can-i-create-stacked-line-graph-with-matplotlib
+
+(http://stackoverflow.com/users/66549/doug)
+
+"""
+import numpy as np
+import matplotlib
+
+__all__ = ['stackplot']
+
+
+def stackplot(axes, x, *args, **kwargs):
+    """Draws a stacked area plot.
+
+    Parameters
+    ----------
+    *x* : 1d array of dimension N
+    *y* : 2d array of dimension MxN, OR any number 1d arrays each of dimension
+          1xN. The data is assumed to be unstacked. Each of the following
+          calls is legal:
+
+          stackplot(x, y)               # where y is MxN
+          staclplot(x, y1, y2, y3, y4)  # where y1, y2, y3, y4, are all 1xNm
+
+    Keyword arguments:
+    *colors* : A list or tuple of colors. These will be cycled through and
+               used to colour the stacked areas.
+               All other keyword arguments are passed to
+               :func:`~matplotlib.Axes.fill_between`
+
+    Returns
+    -------
+    *r* : A list of :class:`~matplotlib.collections.PolyCollection`, one for
+          each element in the stacked area plot.
+    """
+
+    if len(args) == 1:
+        y = np.atleast_2d(*args)
+    elif len(args) > 1:
+        y = np.row_stack(args)
+
+    colors = kwargs.pop('colors', None)
+    if colors is not None:
+        axes.set_color_cycle(colors)
+
+    # Assume data passed has not been 'stacked', so stack it here.
+    y_stack = np.cumsum(y, axis=0)
+
+    r = []
+
+    # Color between x = 0 and the first array.
+    r.append(axes.fill_between(x, 0, y_stack[0,:], facecolor=axes._get_lines.color_cycle.next(), **kwargs))
+
+    # Color between array i-1 and array i
+    for i in xrange(len(y)-1):
+        r.append(axes.fill_between(x, y_stack[i,:], y_stack[i+1,:], facecolor=axes._get_lines.color_cycle.next(), **kwargs))
+    return r