Ability to use solid color to flash instead of transparency

This is not exactly an issue more like feature request or question.

I really like the idea :+1: Good job. But because I use non-solid background, the effect doesn't look like that good with as on the demo gif.

Is there a way to flash by solid color instead of transparency? I mean that you could define blue color & some threshold for blending and this would be used as an "focus" effect.

What do you think?