#
# vest.py - Functions for working with VEST files.
#
# Author: Paul McCarthy <pauldmccarthy@gmail.com>
#
"""This module contains a handful of functions for working with VEST files.
.. autosummary::
:nosignatures:
looksLikeVestLutFile
loadVestLutFile
"""
import numpy as np
[docs]def looksLikeVestLutFile(path):
"""Returns ``True`` if the given ``path`` looks like a VEST LUT file,
``False`` otherwise.
"""
with open(path, 'rt') as f:
lines = []
for i in range(10):
line = f.readline()
if line is None: break
else: lines.append(line.strip())
validHeaders = ('%!VEST-LUT', '%BeginInstance', '%%BeginInstance')
return len(lines) > 0 and lines[0] in validHeaders
[docs]def loadVestLutFile(path, normalise=True):
"""Assumes that the given file is a VEST LUT file, and attempts to load it.
Returns a ``numpy.float32`` array of shape ``(n, 3)``, where ``n`` is the
number of colours in the file.
If ``normalise=True`` (the default), the colour values are normalised to
the range ``0-1``.
"""
with open(path, 'rt') as f:
lines = f.readlines()
# We over-allocate the colour array
# here, and truncate the array after
# reading. idx keepsd track of the
# number of colours read in.
idx = 0
colours = np.zeros((len(lines), 3), dtype=np.float32)
for line in lines:
if not line.startswith('<-color{'):
continue
start = line.index('{') + 1
end = line.index('}')
r, g, b = line[start:end].split(',')
colours[idx, :] = float(r), float(g), float(b)
idx += 1
colours = colours[:idx, :]
if normalise:
cmin = colours.min()
cmax = colours.max()
return (colours - cmin) / (cmax - cmin)
else:
return colours