def get_circular_graph_coords(x, y, node_keys, radius):
# Calculates coordinates in a circle
# returns dictionary containing node keys to coordinates
return_dict = dict() # returns coordinates for each node
assert len(node_keys) > 0
deg_current = 0
deg_increment = float(360 / len(node_keys))
for circle in node_keys:
coords = VectorMath.polar_to_cartesian(deg_current, radius)
coords[0] += x
coords[1] += y
return_dict[circle] = coords
deg_current += deg_increment
return return_dict
def draw_arrow(surface,
x1,
y1,
x2,
y2,
arrow_ends,
arrow_color=(0, 0, 0),
line_width=1,
arrow_width=5,
arrow_height=10):
# draws a line with an arrowhead(s) between two points
assert arrow_ends in ["both", "right"
] # arrow ends. Determines which side gets arrows
assert isinstance(arrow_height, float) or isinstance(arrow_height, int)
assert arrow_height > 0
dist = math.hypot(x2 - x1, y2 - y1) # get distance between two end points
# do nothing if the distance is the same
if dist == 0:
return
# draw line between end points
surface.line((x1, y1, x2, y2), arrow_color, width=line_width)
if arrow_height * 2 <= dist:
# obtain vectors which determine arrow width perpendicular to the line
direction = VectorMath.point_direction((x1, y1), (x2, y2))
left_dir = direction + 90
left_vect = VectorMath.polar_to_cartesian(left_dir, arrow_width)
right_dir = direction + 270
right_vect = VectorMath.polar_to_cartesian(right_dir, arrow_width)
# obtain coordinate arrow_height of way from left end point to right end point
midleft_vect = VectorMath.polar_to_cartesian(direction, arrow_height)
midpoint_left = [x1 + midleft_vect[0], y1 + midleft_vect[1]]
# obtain coordinate (dist - arrow height) of way from left end point to right end point
midright_vect = VectorMath.polar_to_cartesian(direction,
dist - arrow_height)
midpoint_right = [x1 + midright_vect[0], y1 + midright_vect[1]]
# draw left arrow if needed
if arrow_ends == "both":
arrow_left = (midpoint_left[0] + left_vect[0],
midpoint_left[1] + left_vect[1]
) # add left arrow vector to left coord
arrow_right = (midpoint_left[0] + right_vect[0],
midpoint_left[1] + right_vect[1]
) # add right arrow vector to left coord
surface.polygon([arrow_left, arrow_right, (x1, y1)],
fill=arrow_color) # draw triangle for left arrow
# draw right arrow
arrow_left = (midpoint_right[0] + left_vect[0],
midpoint_right[1] + left_vect[1]
) # add left arrow vector to right coord
arrow_right = (midpoint_right[0] + right_vect[0],
midpoint_right[1] + right_vect[1]
) # add left arrow vector to right coord
surface.polygon([arrow_left, arrow_right, (x2, y2)],
fill=arrow_color) # draw triangle for right arrow
