Convert RGBA to HEX

Question

Given a css color value like:

 rgba(0, 0, 0, 0.86) 

How do I convert that to a RGB hex value that takes the alpha component into account, assuming a white background?

Answer 1

Since alpha value both attenuates the background color and the color value, something like this could do the trick:

function rgba2rgb(RGB_background, RGBA_color) {     var alpha = RGBA_color.a;      return new Color(         (1 - alpha) * RGB_background.r + alpha * RGBA_color.r,         (1 - alpha) * RGB_background.g + alpha * RGBA_color.g,         (1 - alpha) * RGB_background.b + alpha * RGBA_color.b     ); } 

(Try it interactively: https://marcodiiga.github.io/rgba-to-rgb-conversion)