updated span selector example

jdh2358 · jdh2358 · commit 9ed970923452 · 2007-06-14T13:29:45.000Z
svn path=/trunk/matplotlib/; revision=3392
diff --git a/examples/widgets/span_selector.py b/examples/widgets/span_selector.py
@@ -1,33 +1,40 @@
 #!/usr/bin/env python
 """
-The SpanSelector is a mouse widget to select a vmin/vmax
-range.  When you left click drag in the axes, a rectangle shows the
-selected region.  When you release, the rectangle disappears and a
-callback is called with min/max.
+The SpanSelector is a mouse widget to select a xmin/xmax range and plot the
+detail view of the selected region in the lower axes
 """
-import pylab
+import numpy as npy
+from pylab import figure, show
 from matplotlib.widgets import SpanSelector
 
-fig = pylab.figure(figsize=(8,6))
+fig = figure(figsize=(8,6))
 ax = fig.add_subplot(211, axisbg='#FFFFCC')
 
-x,y = 4*(pylab.rand(2,100)-.5)
-ax.plot(x,y,'o')
-ax.set_xlim(-2,2)
+x = npy.arange(0.0, 5.0, 0.01)
+y = npy.sin(2*npy.pi*x) + 0.5*npy.random.randn(len(x))
+
+ax.plot(x, y, '-')
 ax.set_ylim(-2,2)
 ax.set_title('Press left mouse button and drag to test')
 
+ax2 = fig.add_subplot(212, axisbg='#FFFFCC')
+line2, = ax2.plot(x, y, '-')
+
 
-def onselect(vmin, vmax):
-    print vmin, vmax
+def onselect(xmin, xmax):
+    indmin, indmax = npy.searchsorted(x, (xmin, xmax))
+    indmax = min(len(x)-1, indmax)
+
+    thisx = x[indmin:indmax]
+    thisy = y[indmin:indmax]
+    line2.set_data(thisx, thisy)
+    ax2.set_xlim(thisx[0], thisx[-1])
+    ax2.set_ylim(thisy.min(), thisy.max())
+    fig.canvas.draw()
 
 # set useblit True on gtkagg for enhanced performance
 span = SpanSelector(ax, onselect, 'horizontal', useblit=False,
                     rectprops=dict(alpha=0.5, facecolor='red') )
 
-ax2 = fig.add_subplot(212)
-ax2.plot([1,2,3])
-
-span2 = SpanSelector(ax2, onselect, 'vertical')
 
-pylab.show()
+show()
diff --git a/lib/matplotlib/cbook.py b/lib/matplotlib/cbook.py
@@ -15,6 +15,10 @@
 
 
 class converter:
+    """
+    Base class for handling string -> python type with support for
+    missing values
+    """
     def __init__(self, missing='Null', missingval=None):
         self.missing = missing
         self.missingval = missingval
@@ -38,7 +42,7 @@ def __init__(self, fmt='%Y-%m-%d', missing='Null', missingval=None):
         self.fmt = fmt
 
     def __call__(self, s):
-        if self.is_missing(): return self.missingval
+        if self.is_missing(s): return self.missingval
         tup = time.strptime(s, self.fmt)
         return datetime.datetime(*tup[:6])
 
@@ -51,7 +55,7 @@ def __init__(self, fmt='%Y-%m-%d', missing='Null', missingval=None):
         converter.__init__(self, missing, missingval)
         self.fmt = fmt
     def __call__(self, s):
-        if self.is_missing(): return self.missingval
+        if self.is_missing(s): return self.missingval
         tup = time.strptime(s, self.fmt)
         return datetime.date(*tup[:3])
 
@@ -61,7 +65,7 @@ def __init__(self, missing='Null', missingval=None):
         converter.__init__(self, missing)
         self.missingval = missingval
     def __call__(self, s):
-        if self.is_missing(): return self.missingval
+        if self.is_missing(s): return self.missingval
         return float(s)
 
 
@@ -71,7 +75,7 @@ def __init__(self, missing='Null', missingval=None):
         converter.__init__(self, missing)
 
     def __call__(self, s):
-        if self.is_missing(): return self.missingval
+        if self.is_missing(s): return self.missingval
         return int(s)
 
 class CallbackRegistry:
diff --git a/lib/matplotlib/mlab.py b/lib/matplotlib/mlab.py
@@ -1444,6 +1444,7 @@ def get_converters(reader):
                 if func is None:
                     func = converterd.get(name)
                 if func is None:
+                    if not item.strip(): continue
                     func = converters[j]
                     func = get_func(item, func)
                 converters[j] = func
