Fix for copy/paste error

Author: coding46

lib/graphviz/utils/colors.rb

@@ -24,21 +24,21 @@ def rgb(r, g, b, a = nil)
  if g.is_a?(Fixnum)
  g = g.to_s.convert_base(10, 16)
  end
- unless g.is_a?(String) and HEX_FOR_COLOR.match(r)
+ unless g.is_a?(String) and HEX_FOR_COLOR.match(g)
  raise ColorException, "Bad green value"
  end
 
  if b.is_a?(Fixnum)
  b = b.to_s.convert_base(10, 16)
  end
- unless b.is_a?(String) and HEX_FOR_COLOR.match(r)
+ unless b.is_a?(String) and HEX_FOR_COLOR.match(b)
  raise ColorException, "Bad blue value"
  end
 
  if a.is_a?(Fixnum)
  a = a.to_s.convert_base(10, 16)
  end
- unless a.nil? or (a.is_a?(String) and HEX_FOR_COLOR.match(r))
+ unless a.nil? or (a.is_a?(String) and HEX_FOR_COLOR.match(a))
  raise ColorException, "Bad alpha value"
  end