"""Utility methods for generating gazemaps."""
import cv2 as cv
import numpy as np
height_to_eyeball_radius_ratio = 1.1
eyeball_radius_to_iris_diameter_ratio = 1.0
def from_gaze2d(gaze, output_size, scale=1.0):
"""Generate a normalized pictorial representation of 3D gaze direction."""
gazemaps = []
oh, ow = np.round(scale * np.asarray(output_size)).astype(np.int32)
oh_2 = int(np.round(0.5 * oh))
ow_2 = int(np.round(0.5 * ow))
r = int(height_to_eyeball_radius_ratio * oh_2)
theta, phi = gaze
theta = -theta
sin_theta = np.sin(theta)
cos_theta = np.cos(theta)
sin_phi = np.sin(phi)
cos_phi = np.cos(phi)
# Draw iris
eyeball_radius = int(height_to_eyeball_radius_ratio * oh_2)
iris_radius_angle = np.arcsin(0.5 * eyeball_radius_to_iris_diameter_ratio)
iris_radius = eyeball_radius_to_iris_diameter_ratio * eyeball_radius
iris_distance = float(eyeball_radius) * np.cos(iris_radius_angle)
iris_offset = np.asarray([
-iris_distance * sin_phi * cos_theta,
iris_distance * sin_theta,
])
iris_centre = np.asarray([ow_2, oh_2]) + iris_offset
angle = np.degrees(np.arctan2(iris_offset[1], iris_offset[0]))
ellipse_max = eyeball_radius_to_iris_diameter_ratio * iris_radius
ellipse_min = np.abs(ellipse_max * cos_phi * cos_theta)
gazemap = np.zeros((oh, ow), dtype=np.float32)
gazemap = cv.ellipse(gazemap, box=(iris_centre, (ellipse_min, ellipse_max), angle),
color=1.0, thickness=-1, lineType=cv.LINE_AA)
gazemaps.append(gazemap)
# Draw eyeball
gazemap = np.zeros((oh, ow), dtype=np.float32)
gazemap = cv.circle(gazemap, (ow_2, oh_2), r, color=1, thickness=-1)
gazemaps.append(gazemap)
return np.asarray(gazemaps)
