Python source code: laue_ellipse.py

import numpy as np

from pymicro.crystal.lattice import *
from pymicro.crystal.microstructure import *
from pymicro.xray.laue import *
from pymicro.xray.detectors import Varian2520

det_distance = 150.
detector = Varian2520()
detector.ref_pos = np.array([det_distance, 0., 0.])
ni = Lattice.face_centered_cubic(0.3524)
phi1, phi, phi2 = (89.4, 92.0, 86.8)  # deg
orientation = Orientation.from_euler([phi1, phi, phi2])
uvw = HklDirection(1, 0, 5, ni)

all_planes = build_list(lattice=ni, max_miller=8)
compute_Laue_pattern(orientation, detector, all_planes, color_field='constant', r_spot=10, inverted=True)

plt.figure()  # new figure
plt.imshow(detector.data.T, cmap=cm.gray, vmin=0, vmax=255)
plt.axis('equal')
plt.xlabel('u coordinate (pixel)')
plt.ylabel('v coordinate (pixel)')
plt.axis([1, detector.size[0], detector.size[1], 1])  # to display with (0, 0) in the top left corner
plt.title("Laue pattern, detector distance = %g" % det_distance)
plt.plot(detector.ucen, detector.vcen, 'ks', label='diffracted beams')
uvw_miller = uvw.miller_indices()
ellipse_mm = compute_ellipsis(orientation, detector, uvw, n=21, verbose=True)
# recalculate the ellipis coordinates in pixel to plot it
ellipse_px = np.zeros((ellipse_mm.shape[0], 2), dtype=np.float)
for i in range(ellipse_mm.shape[0]):
    ellipse_px[i, :] = detector.lab_to_pixel([det_distance, ellipse_mm[i, 0], ellipse_mm[i, 1]])
plt.plot(ellipse_px[:, 0], ellipse_px[:, 1], 'r--', label='ellipse zone [%d%d%d]' % uvw_miller)
plt.legend(numpoints=1, loc='lower right')

image_name = os.path.splitext(__file__)[0] + '.png'
print('writting %s' % image_name)
plt.savefig(image_name, format='png')

from matplotlib import image
image.thumbnail(image_name, 'thumb_' + image_name, 0.2)