Text to show in time_label.

def show_time(self, end=False):
        """Text to show in time_label."""
        if self.time_label is None:
            return

        elapsed_time = time.monotonic() - self.t0
        # System time changed to past date, so reset start.
        if elapsed_time < 0:
            self.t0 = time.monotonic()
            elapsed_time = 0
        if elapsed_time > 24 * 3600:  # More than a day...!
            fmt = "%d %H:%M:%S"
        else:
            fmt = "%H:%M:%S"
        if end:
            color = "#AAAAAA"
        else:
            color = "#AA6655"
        text = "<span style=\'color: %s\'><b>%s" \
               "</b></span>" % (color,
                                time.strftime(fmt, time.gmtime(elapsed_time)))
        self.time_label.setText(text)