generalized fill between poly collection

jdh2358 · jdh2358 · commit bbb419781cc9 · 2008-11-23T19:04:35.000Z
svn path=/trunk/matplotlib/; revision=6432
diff --git a/examples/api/filled_masked_regions.py b/examples/api/filled_masked_regions.py
@@ -8,31 +8,36 @@
 
 
 t = np.arange(0.0, 2, 0.01)
-s = np.sin(2*np.pi*t)
+s1 = np.sin(2*np.pi*t)
+s2 = 1.2*np.sin(4*np.pi*t)
 
 fig = plt.figure()
 ax = fig.add_subplot(111)
-ax.set_title('using fill_between_masked')
-ax.plot(t, s, '-')
+ax.set_title('using fill_between_where')
+ax.plot(t, s1, t, s2)
 ax.axhline(0, color='black', lw=2)
 
-collection = collections.PolyCollection.fill_between_masked(t, s, s>=0, yboundary=0, color='green', alpha=0.5)
+collection = collections.PolyCollection.fill_between_where(
+	   t, s1, s2, s1>=s2, color='green', alpha=0.5)
 ax.add_collection(collection)
 
-collection = collections.PolyCollection.fill_between_masked(t, s, s<=0, yboundary=0, color='red', alpha=0.5)
+collection = collections.PolyCollection.fill_between_where(
+	   t, s1, s2, s1<=s2, color='red', alpha=0.5)
 ax.add_collection(collection)
 
 
 fig = plt.figure()
 ax = fig.add_subplot(111)
 ax.set_title('using span_masked')
-ax.plot(t, s, '-')
+ax.plot(t, s1, '-')
 ax.axhline(0, color='black', lw=2)
 
-collection = collections.BrokenBarHCollection.span_masked(t, s>0, ymin=0, ymax=1, facecolor='green', alpha=0.5)
+collection = collections.BrokenBarHCollection.span_masked(
+	   t, s1>0, ymin=0, ymax=1, facecolor='green', alpha=0.5)
 ax.add_collection(collection)
 
-collection = collections.BrokenBarHCollection.span_masked(t, s<0, ymin=-1, ymax=0, facecolor='red', alpha=0.5)
+collection = collections.BrokenBarHCollection.span_masked(
+	   t, s1<0, ymin=-1, ymax=0, facecolor='red', alpha=0.5)
 ax.add_collection(collection)
 
 
diff --git a/lib/matplotlib/collections.py b/lib/matplotlib/collections.py
@@ -674,7 +674,7 @@ def draw(self, renderer):
 
 
     @staticmethod
-    def fill_between_masked(x, y, mask, yboundary=0, **kwargs):
+    def fill_between_where(x, y1, y2, mask, **kwargs):
         """
         Create a :class:`PolyCollection` filling the regions between *y*
         and *yboundary7* where ``mask==True``
@@ -683,35 +683,50 @@ def fill_between_masked(x, y, mask, yboundary=0, **kwargs):
         *x*
           an N length np array of the x data
 
-        *y*
-          an N length np array of the y data
+        *y1*
+          an N length scalar or np array of the x data
+
+        *y2*
+          an N length scalar or np array of the x data
 
         *mask*
           an N length numpy boolean array
 
-        *yboundary*
-          a scalar to fill between *y* and the boundary
-
         *kwargs*
           keyword args passed on to the :class:`PolyCollection`
 
         """
+	if not cbook.iterable(y1):
+	    y1 = np.ones_like(x)*y1
+
+	if not cbook.iterable(y2):
+	    y2 = np.ones_like(x)*y2
+
+        assert( (len(x)==len(y1)) and (len(x)==len(y2)) )
+
         polys = []
         for ind0, ind1 in mlab.contiguous_regions(mask):
             theseverts = []
             xslice = x[ind0:ind1]
-            yslice = y[ind0:ind1]
+            y1slice = y1[ind0:ind1]
+            y2slice = y2[ind0:ind1]
+
             if not len(xslice):
                 continue
 
             N = len(xslice)
             X = np.zeros((2*N+2, 2), np.float)
-            X[0] = xslice[0], yboundary
-            X[N+1] = xslice[-1], yboundary
+
+            # the purpose of the next two lines is for when y2 is a
+            # scalar like 0 and we want the fill to go all the way
+            # down to 0 even if none of the y1 sample points do
+            X[0] = xslice[0], y2slice[0]
+            X[N+1] = xslice[-1], y2slice[-1]
+
             X[1:N+1,0] = xslice
-            X[1:N+1,1] = yslice
+            X[1:N+1,1] = y1slice
             X[N+2:,0] = xslice[::-1]
-            X[N+2:,1] = yboundary
+            X[N+2:,1] = y2slice[::-1]
 
             polys.append(X)
 
