Cogl.Color.prototype.premultiply
function premultiply(): void { // Gjs wrapper for cogl_color_premultiply() }
Converts a non-premultiplied color to a pre-multiplied color. For example, semi-transparent red is (1.0, 0, 0, 0.5) when non-premultiplied and (0.5, 0, 0, 0.5) when premultiplied.
Since 1.0