Interactive plot based on Tkinter and matplotlib

Question

Dear programmming communauty,

I am trying to perform a "interactive plot" based on Tkinter and pylab.plot in order to plot 1D values. The abssissa are a 1D numpy array x and the ordonates values are in a multidimension array Y, eg.

import numpy
x = numpy.arange(0.0,3.0,0.01)
y = numpy.sin(2*numpy.pi*x)
Y = numpy.vstack((y,y/2))

I want to display y or y/2 (the elements of Y matrix) according to x and change between them with 2 buttons left and right (in order to go to more complex cases). Usually I create some functions like the following to plot graphs.

import pylab
def graphic_plot(n):
    fig = pylab.figure(figsize=(8,5))
    pylab.plot(x,Y[n,:],'x',markersize=2)
    pylab.show()

To add two buttons to change the value of nparameter, I have tried this without success :

import Tkinter
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
class App:
def __init__(self,master):
    # Create a container
    frame = Tkinter.Frame(master)
    frame.pack()
    # Create 2 buttons
    self.button_left = Tkinter.Button(frame,text="<",command=self.decrease)
    self.button_left.pack(side="left")
    self.button_right = Tkinter.Button(frame,text=">",command=self.increase)
    self.button_right.pack(side="left")
    self.canvas = FigureCanvasTkAgg(fig,master=self)
    self.canvas.show()
def decrease(self):
    print "Decrease"
def increase(self):
    print "Increase"
root = Tkinter.Tk()
app = App(root)
root.mainloop()

Can someone help me to understand how to perform such kind of feature ? Many thanks.

What error are you getting? Could you elaborate on "I have tried this without success"? — mgilson
– mgilson, Commented Apr 3, 2012 at 17:29
First, I can't include graph and buttons into a single window. Secondly, I don't know how to change the value of n parameter with the buttons. Thirdly, I don't know how to 'refresh' the graph after cliking on the button. — user1187727
– user1187727, Commented Apr 3, 2012 at 17:35
I don't know about some of those, but to get the canvas to show up, you need to pack it. Googling around a bit, It seems like you might want: canvas.get_tk_widget().pack(side=Tkinter.TOP, fill=Tkinter.BOTH, expand=1) -- or however you want to pack it. (I usually use .grid(), so I'm not sure what the sensible options are to pass to .pack()) — mgilson
– mgilson, Commented Apr 3, 2012 at 17:56
Discussed further in stackoverflow.com/questions/33222030/… and stackoverflow.com/questions/33262433/… — Bennett Brown
– Bennett Brown, Commented Oct 22, 2015 at 13:42

Joe Kington · Accepted Answer · 2012-04-03 18:28:04Z

13

To change the y-values of the line, save the object that's returned when you plot it (line, = ax.plot(...)) and then use line.set_ydata(...). To redraw the plot, use canvas.draw().

As a more complete example based on your code:

import Tkinter
from matplotlib.backends.backend_tkagg import FigureCanvasTkAgg
from matplotlib.figure import Figure

class App:
    def __init__(self, master):
        # Create a container
        frame = Tkinter.Frame(master)
        # Create 2 buttons
        self.button_left = Tkinter.Button(frame,text="< Decrease Slope",
                                        command=self.decrease)
        self.button_left.pack(side="left")
        self.button_right = Tkinter.Button(frame,text="Increase Slope >",
                                        command=self.increase)
        self.button_right.pack(side="left")

        fig = Figure()
        ax = fig.add_subplot(111)
        self.line, = ax.plot(range(10))

        self.canvas = FigureCanvasTkAgg(fig,master=master)
        self.canvas.show()
        self.canvas.get_tk_widget().pack(side='top', fill='both', expand=1)
        frame.pack()

    def decrease(self):
        x, y = self.line.get_data()
        self.line.set_ydata(y - 0.2 * x)
        self.canvas.draw()

    def increase(self):
        x, y = self.line.get_data()
        self.line.set_ydata(y + 0.2 * x)
        self.canvas.draw()

root = Tkinter.Tk()
app = App(root)
root.mainloop()

answered Apr 3, 2012 at 18:28

Joe Kington

287k73 gold badges621 silver badges474 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

user1187727 Over a year ago

This is almost what I want. Thank you. Can you explian me this syntax self.line, = (specially the comma) ? And I lost with this the matplotlib tools (like zoom...), is there a way to bring them back ?

user1187727 Over a year ago

Is it possible to have separated windows (one with classic plot in pylab and a second one with only the two buttons) in order to make this thing simpler to customize ?

Collectives™ on Stack Overflow

Interactive plot based on Tkinter and matplotlib

1 Answer 1

2 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

2 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related