Multiple individual draggable markers with matplotlib

Question

I am learning how to use click events to trigger specific actions in matplotlib, specifically multiple draggable points.

I want to have something similar to what has been done here with a draggable marker. Nonetheless, this specific example only works for one marker. I have two markers, and I want to move them individually.

I tried different approaches based from here, here, here and a matplotlib tutorial, but I wasn't successful when trying to disconnect one of the markers and update the position of the other marker.

This is the image of what I'm looking for. The marker located at x=367 does not move and I would like to move it as well.

This is my code so far, and I'm running it on a jupyter notebook. I'm a bit new to using classes in Python, my apologies if I missed something pretty obvious.

%matplotlib notebook
import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

from matplotlib.pyplot import figure


class DraggableMarker():
    def __init__(self, lines, ax, mark_x, mark_y):
        self.lines = lines
        self.ax = ax
        self.mark_x = mark_x
        self.mark_y = mark_y 

        self.lines = self.lines[:]
        self.tx =  [self.ax.text(0,0,"") for l in self.lines]
        self.marker = [self.ax.plot(mark_x, mark_y, marker="o", color="red")[0]  for l in self.lines]
        self.draggable=False

    def click(self,event):

        # trying to add another marker
#         if event.dblclick:
#             if event.button==3:
#                 self.tx =  [self.ax.text(0,0,"") for l in self.lines]
#                 self.marker1 = [self.ax.plot([0], [0], marker="o", color="red")[0]  for l in self.lines]

        if event.button==2:
            #leftclick
            self.draggable=True
            self.update(event)
        elif event.button==3:
            self.draggable=False
        [tx.set_visible(self.draggable) for tx in self.tx]
        [m.set_visible(self.draggable) for m in self.marker]
        ax.figure.canvas.draw_idle()   


    def drag(self, event):
        if self.draggable:
            self.update(event)
            ax.figure.canvas.draw_idle()

    def release(self,event):

        self.draggable=False

    def update(self, event):
        for i, line in enumerate(self.lines):
            x,y = self.get_closest(line, event.xdata) 
            self.tx[i].set_position((x,y))
            self.tx[i].set_text("x:{}\ny:{}".format(x,y))
            self.marker[i].set_data([x],[y])

    def get_closest(self,line, mx):
        x,y = line.get_data()
        mini = np.argmin(np.abs(x-mx))
        return x[mini], y[mini]

    def connect(self):
        self.c1 = self.ax.figure.canvas.mpl_connect("button_press_event", self.click)
        self.c2 = self.ax.figure.canvas.mpl_connect("button_release_event", self.release)
        self.c3 = self.ax.figure.canvas.mpl_connect("motion_notify_event", self.drag)
        self.lines

    def disconnect(self):
        'disconnect all the stored connection ids'
        self.ax.figure.canvas.mpl_disconnect(self.c1)
        self.ax.figure.canvas.mpl_disconnect(self.c2)
        self.ax.figure.canvas.mpl_disconnect(self.c3)
    

markers_loc = [(367, 1.246216), (425, 1.297134)]

data_df = pd.read_csv('event_number_1.csv')

x = data_df.index
y = data_df['Skin conductance']    

fig, ax = plt.subplots()
plots = [ax.plot(x,y, markevery=[markers_loc[0][0], markers_loc[0][1]]),
        ax.plot(x,y, markevery=[markers_loc[1][0], markers_loc[1][1]])]

cnt=0
for plot in plots:
    plots[cnt]
    ax = plt.gca()
    lines = ax.lines
    dm = DraggableMarker(lines, ax, markers_loc[cnt][0], markers_loc[cnt][1])
    dm.connect()
    cnt+=1

Also, if you could give me some advice regarding how to add a new marker, it would be highly appreciated. Thank you!

Multiple individual draggable markers with matplotlib

0 Answers0