Code review comment for lp://qastaging/~azzar1/unity/dash-layout-2

This is a branch that would have been much easier to review in three different branches:
 * removal of whitespace
 * replacing constants with dash style
 * fixing design bugs

Please think of the reviewers.

  nux::Color color0 = color_;
  color0.alpha = alpha0_;

is not the same as

  nux::Color color0 = color_ * alpha0_;

The first has color0 same r,g,b values as color_ but a different alpha.
The second multiplies all the r,g,b and a values by the alpha.

Apart from that the code looks fine. However can you please add some before and after pictures and get a review from design?