def draw_circle(x1, y1, x2, y2, color, obj=None, canvas=None, thickness=1):
canvas = canvas or obj.widget.canvas
token = str(hash(obj))
r = length(x1, y1, x2, y2)
delta_E = 3
delta_SE = 5 - 2*r
d = 1 - r
x = 0
y = r
put_pixel(x+x1, y+y1, color, canvas, token, thickness=thickness)
while y > x:
if d < 0:
d += delta_E
delta_E += 2
delta_SE += 2
else:
d += delta_SE
delta_E += 2
delta_SE += 4
y -= 1
x += 1
put_pixel(x + x1, y + y1, color, canvas, token, thickness=thickness)
put_pixel(y + x1, x + y1, color, canvas, token, thickness=thickness)
put_pixel(y + x1, -x + y1, color, canvas, token, thickness=thickness)
put_pixel(x + x1, -y + y1, color, canvas, token, thickness=thickness)
put_pixel(-x + x1, y + y1, color, canvas, token, thickness=thickness)
put_pixel(-y + x1, -x + y1, color, canvas, token, thickness=thickness)
put_pixel(-y + x1, x + y1, color, canvas, token, thickness=thickness)
put_pixel(-x + x1, -y + y1, color, canvas, token, thickness=thickness)
def draw_circle_anty_aliasing(
x1, y1, x2, y2, color, obj=None, canvas=None, thickness=1
):
canvas = canvas or obj.widget.canvas
token = str(hash(obj))
r = length(x1, y1, x2, y2)
x = r
y = 0
t = 0
D = lambda r, y: ceil(sqrt(r*r - y*y)) - sqrt(r*r - y*y)
def put_pixel_alphed(x, y, color, canvas, token, alpha, thickness):
put_pixel(x, y, color, canvas, token, alpha=1 - alpha, thickness=thickness)
put_pixel(x-1, y, color, canvas, token, alpha=alpha, thickness=thickness)
while x > y:
y += 1
if D(r, y) < t:
x -= 1
put_pixel_alphed(x+x1, y+y1, color, canvas, token, alpha=D(r, y), thickness=thickness)
put_pixel_alphed(y+x1, x+y1, color, canvas, token, alpha=D(r, y), thickness=thickness)
put_pixel_alphed(y+x1, -x+y1, color, canvas, token, alpha=D(r, y), thickness=thickness)
put_pixel_alphed(x+x1, -y+y1, color, canvas, token, alpha=D(r, y), thickness=thickness)
put_pixel_alphed(-x+x1, -y+y1, color, canvas, token, alpha=1-D(r, y), thickness=thickness)
put_pixel_alphed(-y+x1, -x+y1, color, canvas, token, alpha=1-D(r, y), thickness=thickness)
put_pixel_alphed(-y+x1, x+y1, color, canvas, token, alpha=1-D(r, y), thickness=thickness)
put_pixel_alphed(-x+x1, y+y1, color, canvas, token, alpha=1-D(r, y), thickness=thickness)
t = D(r, y)