Can I approximating the following Tex style color function with Hue function(or other functions):

I tried to use Hue:

ParametricPlot[
 r {Cos[\[Theta]], Sin[\[Theta]]}, {\[Theta], 0, 2 \[Pi]}, {r, 0, 1},
 ColorFunction -> 
  Function[{x, y, \[Theta], r}, Hue@Max[(1 - 2 r), 0]], Axes -> None]

But result is not what I want, notice that the color in the center is same as the outer ring:

This is because the color of Hue[0] is same as Hue[1]. This cause some problems to me, because I have some function value changed from 0 to 1 smoothly, I don't want same color in both side.