import serial



class Display:
	def __init__(self,portname="/dev/ttyUSB0"):
		self.serialport=None
		self.open_port(portname)

	def __del__(self):
		if (not self.serialport == None):
			self.serialport.close()
			self.serialport=None

	def open_port(self,portname):
		self.serialport = serial.Serial(portname,9600,timeout=2,rtscts=True, dsrdtr=True)
		print ("Initializing display:\n  %s\n" % self.serialport )
		self.cmd_reset()
		self.write("Hello world")

	def cmd_reset(self):
		#reset the display
		self.write("\x1b\x40")

	def cmd_cursor_show(self,on=True):
		#show or hide the cursor
		if (on): 
			self.write("\x1f\x43\x01")
		else:
			self.write("\x1f\x43\x00")

	def cmd_blink(self,rate=127):
		self.write("\x1f\x45%c" % rate)

	def cmd_display_on(self,on=True):
		# blink-command: 
		# where the last value defines the blink rate, 
		# with 0=always on, 255=always off
		if (on):
			self.cmd_blink(0)
		else:
			self.cmd_blink(255)

	def cmd_curmode_overwrite(self):
		cmd_curmode(1)			

	def cmd_curmode_vscroll(self):
		cmd_curmode(2)			

	def cmd_curmode_hscroll(self):
		cmd_curmode(3)			

	def cmd_curmode(self,val=2):
		self.write("\x1f%c" % val)

	def cmd_clear(self):
		self.write("\x0c")

	
	def cmd_time(self):
		# activate timer display in lower right corner.
		# actual time has to be set via display_set_timer.
		self.write("\x1f\x55")

	def cmd_time_set(self,h,m):
		# configures hour and minutes of the internal clock and
		# displays the time in the lower right corner.
		# turns off when something gets written into the line.
		# two bytes have to follow with hour and minute
		self.write("\x1F\x54%c%c" % (h,m) )


	def write(self,text):
		self.serialport.write(text)