int gdImageColorExactAlpha (gdImagePtr im, int r, int g, int b, int a)
{
	int i;
	if (im->trueColor) {
		return gdTrueColorAlpha(r, g, b, a);
	}
	for (i = 0; i < im->colorsTotal; i++) {
		if (im->open[i]) {
			continue;
		}
		if ((im->red[i] == r) && (im->green[i] == g) && (im->blue[i] == b) && (im->alpha[i] == a)) {
			return i;
		}
	}
	return -1;
}