Fix bug specifying alpha in a color array. (Thanks, Mátyás János)

mdboom · mdboom · commit 879c8b99ec09 · 2008-06-16T12:14:22.000Z
svn path=/trunk/matplotlib/; revision=5554
diff --git a/lib/matplotlib/colors.py b/lib/matplotlib/colors.py
@@ -291,11 +291,15 @@ def to_rgba(self, arg, alpha=None):
         """
         try:
             if not cbook.is_string_like(arg) and cbook.iterable(arg):
-                if len(arg) == 4 and alpha is None:
+                if len(arg) == 4:
                     if [x for x in arg if (float(x) < 0) or  (x > 1)]:
                         # This will raise TypeError if x is not a number.
                         raise ValueError('number in rbga sequence outside 0-1 range')
-                    return tuple(arg)
+                    if alpha is None:
+                        return tuple(arg)
+                    if alpha < 0.0 or alpha > 1.0:
+                        raise ValueError("alpha must be in range 0-1")
+                    return arg[0], arg[1], arg[2], arg[3] * alpha
                 r,g,b = arg[:3]
                 if [x for x in (r,g,b) if (float(x) < 0) or  (x > 1)]:
                     raise ValueError('number in rbg sequence outside 0-1 range')
