get data example

jdh2358 · jdh2358 · commit fe55936f3ebc · 2009-08-04T13:15:14.000Z
svn path=/trunk/matplotlib/; revision=7345
diff --git a/CHANGELOG b/CHANGELOG
@@ -1,8 +1,13 @@
+
 2009-08-03 Add PathCollection; modify contourf to use complex
            paths instead of simple paths with cuts. - EF
 
 2009-08-03 Fixed boilerplate.py so it doesn't break the ReST docs. - JKS
 
+2009-07-31 Added cbook.get_mpl_data for urllib enabled fetching and
+           cacheing of data needed for examples.  See
+           examples/misc/mpl_data_demo.py - JDH
+
 ======================================================================
 
 2009-07-31 Tagging 0.99.0.rc1 at 7314 - MGD
diff --git a/examples/misc/mpl_data_demo.py b/examples/misc/mpl_data_demo.py
@@ -0,0 +1,12 @@
+    """
+    Grab mpl data from the ~/.matplotlib/mpl_data cache if it exists, else
+    fetch it from svn and cache it
+    """
+import matplotlib.cbook as cbook
+import matplotlib.pyplot as plt
+fname = cbook.get_mpl_data('lena.png', asfileobj=False)
+
+print 'fname', fname
+im = plt.imread(fname)
+plt.imshow(im)
+plt.show()
diff --git a/examples/pylab_examples/scatter_demo2.py b/examples/pylab_examples/scatter_demo2.py
@@ -1,7 +1,7 @@
 """
 make a scatter plot with varying color and size arguments
 """
-import matplotlib 
+import matplotlib
 import numpy as np
 import matplotlib.pyplot as plt
 import matplotlib.mlab as mlab
diff --git a/lib/matplotlib/__init__.py b/lib/matplotlib/__init__.py
@@ -487,6 +487,7 @@ def _get_data_path_cached():
                              always=False)
 
 
+
 def get_example_data(fname):
     """
     return a filehandle to one of the example files in mpl-data/example
diff --git a/lib/matplotlib/cbook.py b/lib/matplotlib/cbook.py
@@ -10,6 +10,8 @@
 import numpy.ma as ma
 from weakref import ref
 
+import matplotlib
+
 major, minor1, minor2, s, tmp = sys.version_info
 
 
@@ -338,6 +340,55 @@ def to_filehandle(fname, flag='rU', return_opened=False):
 def is_scalar_or_string(val):
     return is_string_like(val) or not iterable(val)
 
+
+
+def get_mpl_data(fname, asfileobj=True):
+    """
+    Check the cachedirectory ~/.matplotlib/mpl_data for an mpl_data
+    file.  If it does not exist, fetch it with urllib from the mpl svn repo
+
+      http://matplotlib.svn.sourceforge.net/viewvc/matplotlib/trunk/mpl_data/
+
+    and store it in the cachedir.
+
+    If asfileobj is True, a file object will be returned.  Else the
+    path to the file as a string will be returned
+
+    To add a datafile to this directory, you need to check out
+    mpl_data from matplotlib svn::
+
+      svn co https://matplotlib.svn.sourceforge.net/svnroot/matplotlib/mpl_data
+
+    and svn add the data file you want to support.  This is primarily
+    intended for use in mpl examples that need custom data
+    """
+
+    # TODO: how to handle stale data in the cache that has been
+    # updated from svn -- is there a clean http way to get the current
+    # revision number that will not leave us at the mercy of html
+    # changes at sf?
+
+
+    configdir = matplotlib.get_configdir()
+    cachedir = os.path.join(configdir, 'mpl_data')
+    if not os.path.exists(cachedir):
+        os.mkdir(cachedir)
+
+    cachefile = os.path.join(cachedir, fname)
+
+    if not os.path.exists(cachefile):
+        import urllib
+        url = 'http://matplotlib.svn.sourceforge.net/viewvc/matplotlib/trunk/mpl_data/%s'%urllib.quote(fname)
+        matplotlib.verbose.report('Attempting to download %s to %s'%(url, cachefile))
+        urllib.urlretrieve(url, filename=cachefile)
+    else:
+        matplotlib.verbose.report('Aleady have mpl_data %s'%fname)
+
+    if asfileobj:
+        return to_filehandle(cachefile)
+    else:
+        return cachefile
+
 def flatten(seq, scalarp=is_scalar_or_string):
     """
     this generator flattens nested containers such as
