Make sure the text is always visible as much as possible

I am given a text that is placed on top of a background of a given color. I need a way to determine the monochrome color the text should have to ensure the text's maximum visibility.

My intuition: take the background color, invert it and make it monochrome - this is the color the text should have. Is this correct? This does seem to work, but I am not sure if the method is infallible. Perhaps this method does work, but there is a simpler way to do this?