_cairo_color_get_rgb (cairo_color_t *color, double *red, double *green, double *blue)
_cairo_color_get_rgb (const cairo_color_t *color, double *red, double *green, double *blue)
_cairo_color_get_rgb (cairo_color_t *color, double *red, double *green, double *blue){    if (red)	*red   = color->red;    if (green)	*green = color->green;    if (blue)	*blue  = color->blue;}