from __future__ import division
#!/usr/bin/env python
# resolution_corners.py
#
#   Copyright (C) 2013 Diamond Light Source, Graeme Winter
#
#   This code is distributed under the BSD license, a copy of which is
#   included in the root directory of this package.
#
# Print out the resolution (two-theta) of the corners of the detector

def resolution_corners(frame):
  '''Compute the resolution limit corresponding to the corners of the detector
  surface.'''

  import math
  from scitbx import matrix

  detector = frame.get_detector()
  beam = frame.get_beam()

  nfast, nslow = map(int, detector.get_image_size())
  dfast, dslow = detector.get_pixel_size()
  F = matrix.col(detector.get_fast_axis())
  S = matrix.col(detector.get_slow_axis())
  origin = matrix.col(detector.get_origin())

  s0 = -1 * matrix.col(beam.get_direction())

  for ds in 0, 1:
    for df in 0, 1:
      corner = origin + nfast * dfast * F * df + nslow * dslow * S * ds
      theta = 0.5 * corner.angle(s0)
      print '%.3f' % (beam.get_wavelength() / (2 * math.sin(theta)))

if __name__ == '__main__':

  import sys
  import dxtbx

  resolution_corners(dxtbx.load(sys.argv[1]))