EXCLUSION

{@usesMathJax} Subtracts darker from lighter with lower contrast.

\begin{equation} \alpha_{out} = \alpha_{src} + \alpha_{dst} - \alpha_{src} * \alpha_{dst} \end{equation}

\begin{equation} C_{out} = C_{src} + C_{dst} - 2 * C_{src} * C_{dst} \end{equation}