mplbezier

This module allows you to draw Bezier curves interactively in matplotlib and load them again afterwards. You can install the package from PyPi:

pip install mplbezier

Simply import Bezier from mplbezier and create a new Bezier object, which you pass both the Axis and a filename of a pickle file to store the anchor point data. Using Bezier.enable, you enable the interactive drawing mode. In order to use the interactive drawing mode, you need to be inside an interactive matplotlib backend, such as qtagg. If you are using this module from a Jupyter notebook, switch to interactive mode using magic commands such as %matplotlib Qt at the top of the cell.

import matplotlib.pyplot as plt
from mplbezier import Bezier

fig, ax = plt.subplots()

b = Bezier(ax, 'my_curve.pkl')
b.enable()

plt.show()

By clicking with the left mouse button inside the plot, you will generate a new anchor point. By clicking on an anchor point, you can reveal the handles with which you can define the position of the control points. By dragging a point, you can move it on the axis. By right clicking a point, you can remove it from the Bezier curve. If the point lies between two other points, the curve will automatically connect the two surrounding points with each other. Moreover, "ctrl+z" is supported to undo your last action.

Once you are satisfied with your curve, you can remove or comment out the line b.enable(). This will remove the anchor points from the curve, thereby giving you the final plot.

The curve can be initialized with three keyword arguments:

• c sets the color (default 'black')
• lw sets the linewidth (default 1)
• ls sets the linestyle (default ('-')