[Python] Extension using inheritance of matplotlib (NavigationToolbar2TK)

Personal memorandum.

Issue setting

--In the next product, we aim to be able to analyze data using matplotlib plots, but since it is a little inflexible, we would like to add a GUI so that Tkinter can operate graphs freely.

--Therefore, we will extend NavigationToolbar2TK, which is the default navigation toolbar.

Collection of examples

Hide some buttons displayed in the Navigation Toolbar

Source code

disable_somebuttons.py

import matplotlib.pyplot as plt
import tkinter as tk

from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)

class NavigationToolbarExt(NavigationToolbar2Tk):
    toolitems = [t for t in NavigationToolbar2Tk.toolitems if t[0] in ('Pan', 'Save')]

## ---abridgement--- ##
##Below is the main program###

root = tk.Tk()
fig = plt.figure(figsize=(8, 5))

canvas = FigureCanvasTkAgg(fig, master=root)
canvas.draw()

toolbar = NavigationToolbarExt(canvas, root)

canvas.get_tk_widget().pack(side=tk.TOP, fill=tk.BOTH, expand=1)
toolbar.pack(side=tk.BOTTOM, fill=tk.BOTH)

root.protocol("WM_DELETE_WINDOW", toolbar.quit)
root.mainloop()

Execution result

Only Pan and Save will be displayed.

Add a new button to the Navigation Toolbar using a custom icon

--Add a declaration statement related to self._buttons to the constructor.

――In addition, ToolTip will not work with this alone, so I will add a sentence about ToolTip.

--Currently, toggle = False, but there is a possibility that toggle = True can be supported by overriding another method. (Investigation required)

• However, although this method can be tentatively done, it is not good to describe such a method with "_" at the beginning, so it is necessary to consider another method ...

originalbutton.py

import matplotlib.pyplot as plt
import tkinter as tk

from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)
from matplotlib.backends._backend_tk import (ToolTip)

class NavigationToolbarExt(NavigationToolbar2Tk):
    toolitems = [t for t in NavigationToolbar2Tk.toolitems if t[0] in ('Pan', 'Save')]

    def __init__(self, canvas=None, master=None):
        super().__init__(canvas, master)

        # move2.With png as an icon, when that button is clicked, a member method called HelloWorld is executed.
        #In addition, Foo as ToolTip?Is displayed.
        self._buttons["Foo"] = (self._Button('Foo', 'move2.png', toggle=False , command=getattr(self, 'HelloWorld'))) 
        ToolTip.createToolTip(self._buttons["Foo"], 'Foo?')
        self.canvas = canvas
        self.master = master

    def HelloWorld(self):
        print("HelloWorld")

### (Omitted below) ###

In subplot, change the process so that only some graphs (here, subplot 1st) can be panned.

--Override press_pan

pan_somegraph.py

import matplotlib.pyplot as plt
import tkinter as tk

from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)

class NavigationToolbarExt(NavigationToolbar2Tk):
    def press_pan(self, event):
        if( event.inaxes != None):  #When clicked outside the frame(event.inaxes==None)Want to ignore
            if event.inaxes.get_subplotspec().colspan.start == 1:   #Only the one specified as No. 1 is targeted
                super().press_pan(event)

### (Omitted below) ###

Don't accept click events while panning

--Override pan

--In C #, the delegate operator (+ =,-=) is often used to control whether or not an event can be accepted, but it was implemented using the same principle. The corresponding functions are mpl_connect and mpl_disconnect.

Note that if you don't put a button event in the constructor as well, the click of the first action will be ignored. The constructor is also light but needs to be implemented.

pan_click_available_onlyidle.py

import matplotlib.pyplot as plt
import tkinter as tk

from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)
from matplotlib.backend_bases import (_Mode)

class NavigationToolbarExt(NavigationToolbar2Tk):
    toolitems = [t for t in NavigationToolbar2Tk.toolitems if t[0] in ('Pan', 'Save')]

    def __init__(self, canvas=None, master=None):
        super().__init__(canvas, master)
        self.canvas = canvas
        self.master = master

        self.pressevent_cid = fig.canvas.mpl_connect('button_press_event', self.onclick)  #Need here

    def pan(self):
        super().pan()
        if self.mode == _Mode.PAN:  #When in PAN mode
            fig.canvas.mpl_disconnect(self.pressevent_cid)    #Delete event
        else:  #If not in PAN mode
            self.pressevent_cid = fig.canvas.mpl_connect('button_press_event', self.onclick)  #Add an event

    def onclick(self, event):
        print("Clicked")

## (Omitted below) ###

Change the background color of the Navigation Toolbar

When I made a pull request, I received another proposal. This may be the cleanest form. However, there are some concerns when setting a color other than the background color.

import matplotlib.pyplot as plt
import tkinter as tk

from matplotlib.backends.backend_tkagg import (FigureCanvasTkAgg, NavigationToolbar2Tk)

class NavigationToolbarExt(NavigationToolbar2Tk):
    def __init__(self, canvas=None, master=None):
        super().__init__(canvas, master)   
        self.canvas = canvas
        self.master = master

        self['bg'] = 'white'
        for item in self.winfo_children():
           item['bg'] = 'white'

Accept end event

Since tkinter is used, python.exe may not end unless the following syntax is added to the main routine, so be careful.

root.protocol("WM_DELETE_WINDOW", toolbar.quit)