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IRIDAS .look to .csp LUT
"""From the seemingly undocumented IRIDAS .look format to .csp
"""
import re
import os
import sys
import struct
import binascii
import xml.etree.ElementTree as ET
class LookParsingError(Exception):
pass
def warn(msg):
sys.stderr.write("%s\n" % msg)
def chunks(l, n):
""" Yield successive n-sized chunks from l.
"""
for i in xrange(0, len(l), n):
yield l[i:i+n]
class LookParser(object):
"""Slightly hacky parser for IRIDAS's .look LUT
"""
def __init__(self, source):
"""source is string containing .look file contents
"""
tree = ET.fromstring(source)
self.lut3d = self.parse_lut3d(tree)
def parse_lut3d(self, tree):
"""Parses the LUT section of the .look, which contains a
edge-size and binary 3D LUT.
Data is packed series of (float, float, float), and probably
something else (there is a suspicious 12 bytes left over..)
"""
# Data to return
lut3d = {}
# Get 3D LUT edge size from
# <LUT>
# <size>"8"</size>
lut = tree.find("LUT")
cube_edge_size = int(lut.find("size").text.replace("\"", ""))
lut3d['edgelen'] = cube_edge_size
# Clean up LUT data - remove whitespace, quotes etc
lutdata = lut.find("data").text
lutdata = re.sub("[^A-Z0-9]+", "", lutdata)
# Parse 3D LUT data
data_binary = binascii.unhexlify(lutdata)
# Little endian, 3 floats
format = "<fff"
samples = list(struct.unpack(format, chunk) for chunk in chunks(data_binary, struct.calcsize(format)))
if len(samples) != cube_edge_size ** 3:
raise LookParsingError("Cube size was not correct, was %s, expected %s (%s**3)" % (
len(samples),
cube_edge_size**3,
cube_edge_size))
lut3d['samples'] = samples
return lut3d
def csp_header_with_noop_prelut():
lines = []
lines.append("CSPLUTV100")
lines.append("3D")
lines.append("")
for x in range(3):
lines.append("2")
lines.append("0.0 1.0")
lines.append("0.0 1.0")
lines.append("")
return lines
def main(in_fname = None):
if in_fname is None:
in_fname = sys.argv[1]
f = open(in_fname)
contents = f.read()
p = LookParser(contents)
outcsp = csp_header_with_noop_prelut()
outcsp.append("%s %s %s" % ((p.lut3d['edgelen'],)*3))
for s in p.lut3d['samples']:
outcsp.append("%.05f %.05f %.05f" % s)
out_fname = os.path.splitext(in_fname)[0] + ".csp"
df = open(out_fname, "w")
df.write("\n".join(outcsp))
df.close()
if __name__ == "__main__":
main()
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