Merge pull request #4919 from tacaswell/issue08

tacaswell · tacaswell · commit 19c5d015df9e · 2015-08-13T22:35:33.000-04:00
FIX: fix divide by zero in short arrows
diff --git a/lib/matplotlib/patches.py b/lib/matplotlib/patches.py
@@ -3308,7 +3308,10 @@ def transmute(self, path, mutation_size, linewidth):
             x0, y0 = path.vertices[0]
             x1, y1 = path.vertices[1]
 
-            if self.beginarrow:
+            # If there is no room for an arrow and a line, then skip the arrow
+            has_begin_arrow = (self.beginarrow and
+                               not ((x0 == x1) and (y0 == y1)))
+            if has_begin_arrow:
                 verticesA, codesA, ddxA, ddyA = \
                            self._get_arrow_wedge(x1, y1, x0, y0,
                                                  head_dist, cos_t, sin_t,
@@ -3321,7 +3324,9 @@ def transmute(self, path, mutation_size, linewidth):
             x2, y2 = path.vertices[-2]
             x3, y3 = path.vertices[-1]
 
-            if self.endarrow:
+            # If there is no room for an arrow and a line, then skip the arrow
+            has_end_arrow = (self.endarrow and not ((x2 == x3) and (y2 == y3)))
+            if has_end_arrow:
                 verticesB, codesB, ddxB, ddyB = \
                            self._get_arrow_wedge(x2, y2, x3, y3,
                                                  head_dist, cos_t, sin_t,
@@ -3338,7 +3343,7 @@ def transmute(self, path, mutation_size, linewidth):
                           path.codes)]
             _fillable = [False]
 
-            if self.beginarrow:
+            if has_begin_arrow:
                 if self.fillbegin:
                     p = np.concatenate([verticesA, [verticesA[0],
                                                     verticesA[0]], ])
@@ -3349,7 +3354,7 @@ def transmute(self, path, mutation_size, linewidth):
                     _path.append(Path(verticesA, codesA))
                     _fillable.append(False)
 
-            if self.endarrow:
+            if has_end_arrow:
                 if self.fillend:
                     _fillable.append(True)
                     p = np.concatenate([verticesB, [verticesB[0],
