This sample script demonstrates the basics for connecting to the preview socket, setting the resolution, and the pixel format, and reading back a floating point buffer of the image.

previewSocketExample.py

'''
	This sample script demonstrates the basics for connecting to the preview
	socket, setting the resolution, and the pixel format, and reading back a
	floating point buffer of the image.
	
	To test it, launch modo, and execute the command:
		telnet.listen port:5678 raw:true
		
	Then run the following in an external Python client.
'''
import socket
import struct

def testPreviewSocket(address, port):
	preview = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
	preview.connect((address, port))

	preview.send(struct.pack("<I", 0x10000000|0x00001000))	# LXiPREVIEWMSG_REQ_SET_PROTOCOL
	preview.send(struct.pack("<B", 0))			# 0
	result = struct.unpack("<I", preview.recv(4))
	if result[0] != (0x20000000|0x00001000):		# LXiPREVIEWMSG_ACK_PROTOCOL_SET
		print "LXiPREVIEWMSG_REQ_SET_FORMAT failed"
		return
	
	# Set the resolution.
	preview.send(struct.pack("<I", 0x10000000|0x00002000))	# LXiPREVIEWMSG_REQ_SET_RES
	preview.send(struct.pack("<I", 100))			# 100
	preview.send(struct.pack("<I", 100))			# 100
	result = struct.unpack("<I", preview.recv(4))		# Should be LXiPREVIEWMSG_ACK_RES_SET
	if result[0] != (0x20000000|0x00002000):
		print "LXiPREVIEWMSG_REQ_SET_RES failed"
		return

	# Set the format.
	preview.send(struct.pack("<I", 0x10000000|0x00002001))	# LXiPREVIEWMSG_REQ_SET_FORMAT
	preview.send(struct.pack("<I", 0x08))			# LXiIMD_FLOAT - floating point RGBA
	result = struct.unpack("<I", preview.recv(4))
	if result[0] != (0x20000000|0x00002001):		# LXiPREVIEWMSG_ACK_FORMAT_SET
		print "LXiPREVIEWMSG_REQ_SET_FORMAT failed"
		return

	# Rad the RGBA pixel buffer back.
	preview.send(struct.pack("<I", 0x10000000|0x00003000))	# LXiPREVIEWMSG_REQ_SEND_FULL_FRAME
	result = struct.unpack("<I", preview.recv(4))
	if result[0] & (0x20000000|0x00003000|0x00000002):	# LXiPREVIEWMSG_ACK_SEND_FULL_FRAME_RGBAFP
		width = (struct.unpack("<I", preview.recv(4)))[0]
		height = (struct.unpack("<I", preview.recv(4)))[0]
		buffer = preview.recv((width*16)*height)
		format = "<" + ("f" * ((width*4)*height))
		pixels = struct.unpack(format, buffer)
		print pixels
	else
		print "LXiPREVIEWMSG_REQ_SEND_FULL_FRAME failed"
		return

telnet = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
telnet.connect(("127.0.0.1", 5678))
telnet.sendall("previewSocket.listen port:1234 open:true\0")

testPreviewSocket("127.0.0.1", 1234)