I'm just learning to use your library, so please excuse me if it is written somewhere, but I couldn't find anything.

First: thanks for providing this fine library and all the useful documentation (and demos!)!

Starting to use it, I got confused. I used this piece of code:

func p(a *pterm.AreaPrinter) {

	foregroundRGB := pterm.RGB{R: 0, G: 0, B: 0}
	backgroundRGB := pterm.RGB{R: 255, G: 0, B: 0}
	aRGBStyle := pterm.NewRGBStyle(foregroundRGB, backgroundRGB)
	aStyle := pterm.NewStyle(pterm.FgBlack,pterm.BgLightRed)
	for i := 0; i < 5; i++ {
		if i%2 == 0 {
			a.Update(aStyle.Sprintf("Current count: %d\n",i))
		} else {
			a.Update(aRGBStyle.Sprintf("Current count: %d\n",i))			
		}
		time.Sleep(time.Second)
	}
}

• the astyle.Sprintf behave like I would expect it to behave (and consistently with fmt.Sprintf): it outputs the string with the style applied.
• the aRGBStyle.Sprintf however, complains about a format mismatch: Current count: %!d(string=1) and even if you change the %d into a %s (which makes no sense?), only the value of i is printed in the style. "Current count: " is still the default (white on black in my case). Only if you do a aRGBSyle.Sprintf("%s\n", "Current count: ", i) (with only the %s in the format, not %s%d as one might expect) I got what I expected.

As said: maybe it's written somewhere, but I couldn't find the difference being mentioned in the documentation and at least IMHO it would be easier if these two Sprintf calls would behave consistently.