Convert color in format 'rgb(RRR,GGG,BBB)', 'rgba(RRR,GGG,BBB,alpha)',  
    '#RRGGBB', or limited English color name (eg 'red') to tuple (RRR, GGG, BBB)

def rgb_tuple_from_str(color_string):
    """Convert color in format 'rgb(RRR,GGG,BBB)', 'rgba(RRR,GGG,BBB,alpha)',  
    '#RRGGBB', or limited English color name (eg 'red') to tuple (RRR, GGG, BBB)
    """
    try:
        # English color names (limited)
        rgb_string = common_html_colors[color_string]
        return tuple([float(x) for x in re.findall(r'\d{1,3}', rgb_string)]) 
    
    except KeyError:
        try:
            # HEX color code
            hex_string = color_string.lstrip('#')
            return tuple(int(hex_string[i:i+2], 16) for i in (0, 2 ,4))
        
        except ValueError:
            # RGB or RGBA formatted strings
            return tuple([int(x) if float(x) > 1 else float(x) 
                          for x in re.findall(r"[-+]?\d*\.*\d+", color_string)])