vertex_representation_of_shape_contour

vertex_representation_of_shape_contour.py

import expyriment
from expyriment.misc import geometry
import math as _math

def _contour_of_edge(node_A, node_B, node_C, line_width):
    # using nodes in cartesian coordinates
    BA = (node_B[0] - node_A[0], node_B[1] - node_A[1])  # vector B-A
    BC = (node_B[0] - node_C[0], node_B[1] - node_C[1])

    phi_BC = _math.atan2(BC[1], BC[0]) # polar coordinate phi (angle) from cartesian
    phi_sum = _math.atan2(BA[1]+BC[1], BA[0]+BC[0])
    rho = line_width/_math.sin(phi_BC - phi_sum)

    V = (0.5*rho*_math.cos(phi_sum), 0.5*rho*_math.sin(phi_sum)) # polar to cartesian
    p1 = (node_B[0] + V[0], node_B[1] + V[1])
    p2 = (node_B[0] - V[0], node_B[1] - V[1])
    return (p1, p2)

def vertex_representation_of_shape_contour(points_xy, line_width):
    # vertex representation of shape contores #TODO
    l = len(points_xy)
    outer_array = []
    inner_array = []
    for b in range(l):
        a = b-1
        if a<0:
            a = l-1
        c = b+1
        if c>l-1:
            c=0
        p1, p2 = _contour_of_edge(points_xy[a], points_xy[b], points_xy[c], line_width)
        outer_array.append(p1)
        inner_array.append(p2)

    outer_array.append(outer_array[0])
    inner_array.append(inner_array[0])
    return outer_array + list(reversed(inner_array))


line_width = 8
points =[ (100, 0),
         (00, 200),
         (50, -200 )]


expyriment.control.set_develop_mode()

exp = expyriment.control.initialize()
expyriment.control.start(skip_ready_screen=True)


s = expyriment.stimuli.Shape(colour=(255,255,255), line_width=line_width)
s.add_vertices(geometry.points_to_vertices( points ))
s.present()
exp.keyboard.wait()



s = expyriment.stimuli.Shape(colour=(255,255,255), line_width=1)
v = vertex_representation_of_shape_contour(points, line_width)
s.add_vertices(geometry.points_to_vertices( v ))
s.present()
exp.keyboard.wait()


s = expyriment.stimuli.Shape(colour=(255,255,255), line_width=0)
v = vertex_representation_of_shape_contour(points, line_width)
s.add_vertices(geometry.points_to_vertices( v ))
s.present()
exp.keyboard.wait()



expyriment.control.end()