def draw_text(self, x, y, string):
        font_bytes = self.font.bytes
        font_rows = self.font.rows
        font_cols = self.font.cols
        for c in string:
            p = ord(c) * font_cols
            for col in range(0, font_cols):
                mask = font_bytes[p]
                p += 1
                for row in range(0, 8):
                    self.draw_pixel(x, y + row, mask & 0x1)
                    mask >>= 1
                x += 1