I'm drawing here Bezier curve, but I'm planning to save the picture as transparent format without background. According to my plotting below, I would like to make the background transparent like the PNG figures without background. I need just the curve and axes to be shown. I tried and saved it as PNG, but it didn't work. Is it possible? Any assistance, please?
My Python code:
import numpy as np
import scipy.special
import matplotlib.pyplot as plt
def calc_bezier_path(control_points, n_points=100):
"""
Compute bezier path (trajectory) given control points.
:param control_points: (numpy array)
:param n_points: (int) number of points in the trajectory
:return: (numpy array)
"""
traj = []
for t in np.linspace(0, 1, n_points):
traj.append(bezier(t, control_points))
return np.array(traj)
def bernstein_poly(n, i, t):
"""
Bernstein polynom.
:param n: (int) polynom degree
:param i: (int)
:param t: (float)
:return: (float)
"""
return scipy.special.comb(n, i) * t ** i * (1 - t) ** (n - i)
def bezier(t, control_points):
"""
Return one point on the bezier curve.
:param t: (float) number in [0, 1]
:param control_points: (numpy array)
:return: (numpy array) Coordinates of the point
"""
n = len(control_points) - 1
return np.sum([bernstein_poly(n, i, t) * control_points[i] for i in range(n + 1)], axis=0)
def line_bezier(visx, visy, control, mod="nothing"):
vis = np.column_stack((visx,visy))
path_x, path_y = np.array([]),np.array([])
setting = {"nothing":[len(vis)-2, 1, 1], "start":[len(vis)-1, 0, 0], "end":[len(vis)-1, 1, 0], "both":[len(vis), 0, -1]}
epoch = setting[mod][0]
start = setting[mod][1]
end = setting[mod][2]
if len(vis) > 2:
current_control = vis[0]
for x in range(epoch):
if x != (epoch-1):
for y in control:
mid_control = [(vis[x+start,0]+(vis[x+(start+1),0]-vis[x+start,0])*y), (vis[x+start,1]+(vis[x+(start+1),1]-vis[x+start,1])*y)]
mid_control2 = [(vis[x+start,0]+(vis[x+(start+1),0]-vis[x+start,0])*y-0.1), (vis[x+start,1]+(vis[x+(start+1),1]-vis[x+start,1])*y-0.1)]
if y == control[0]:
#plt.annotate(f"M{x}", mid_control)
plt.annotate("*", mid_control2)
bezier_line = calc_bezier_path(np.array([current_control,vis[x+start], mid_control]))
path_x = np.append(path_x, bezier_line.T[0])
path_y = np.append(path_y, bezier_line.T[1])
current_control = mid_control
else:
mid_control = [(vis[x+start,0]+(vis[x+(start+1),0]-vis[x+start,0])*y), (vis[x+start,1]+(vis[x+(start+1),1]-vis[x+start,1])*y)]
#plt.annotate(f"M{x}", mid_control)
plt.annotate("*", mid_control2)
bezier_line = calc_bezier_path(np.array([current_control, mid_control]))
path_x = np.append(path_x, bezier_line.T[0])
path_y = np.append(path_y, bezier_line.T[1])
current_control = mid_control
else:
if mod == "end" or mod == "both":
bezier_line = calc_bezier_path(np.array([current_control, vis[x+(end+1)]]))
else:
bezier_line = calc_bezier_path(np.array([current_control, vis[x+end], vis[x+(end+1)]]))
path_x = np.append(path_x, bezier_line.T[0])
path_y = np.append(path_y, bezier_line.T[1])
else:
path_x, path_y = visx, visy
return path_x, path_y
visx, visy = [1,2,10,15,20,25,21], [0,5,1,4,2,3,3]
control = [0.25,0.75]
path_x, path_y = line_bezier(visx, visy, control,mod="end")
plt.plot(path_x, path_y)
plt.plot(visx, visy, "--o")
for a,b in zip(np.linspace(0,visx[-1],num=100), np.linspace(0,visy[-1],num=100)):
for n in control:
if n == round(a,1):
plt.scatter(n, b)
for xy in range(len(visx)):
plt.annotate(f"P{xy}", [visx[xy], visy[xy]])
plt.xlabel('X')
plt.ylabel('Y')
plt.show()
