apodemus apodemus - 1 year ago 147
Python Question

python matplotlib and PyQT for multi-tab plotting - navigation

I've created a qt app that can be used to display matplotlib figures in multiple tabs. Now I'm trying to get the standard matplotlib navigation toolbar to work for all the figures in the various tabs. So far I've only managed to get it working in one of the figures, but not all.

Here's the code:

from PyQt4 import QtCore
from PyQt4 import QtGui as qt

from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QTAgg as NavigationToolbar
from matplotlib.figure import Figure

import itertools

class MultiTabNavTool(NavigationToolbar):
def __init__(self, canvases, tabs, parent=None):
self.canvases = canvases
self.tabs = tabs

NavigationToolbar.__init__(self, canvases[0], parent)

def get_canvas(self):
return self.canvases[self.tabs.currentIndex()]

def set_canvas(self, canvas):
self._canvas = canvas

canvas = property(get_canvas, set_canvas)

class MplMultiTab(qt.QMainWindow):
def __init__(self, parent=None, figures=None, labels=None):
qt.QMainWindow.__init__(self, parent)

self.main_frame = qt.QWidget()
self.tabWidget = qt.QTabWidget( self.main_frame )
self.create_tabs( figures, labels )

# Create the navigation toolbar, tied to the canvas
self.mpl_toolbar = MultiTabNavTool(self.canvases, self.tabWidget, self.main_frame)

self.vbox = vbox = qt.QVBoxLayout()


def create_tabs(self, figures, labels ):

if labels is None: labels = []
figures = [Figure()] if figures is None else figures #initialise with empty figure in first tab if no figures provided
self.canvases = [self.add_tab(fig, lbl)
for (fig, lbl) in itertools.zip_longest(figures, labels) ]

def add_tab(self, fig=None, name=None):
'''dynamically add tabs with embedded matplotlib canvas with this function.'''

# Create the mpl Figure and FigCanvas objects.
if fig is None:
fig = Figure()
ax = fig.add_subplot(111)

canvas = fig.canvas if fig.canvas else FigureCanvas(fig)
canvas.setFocusPolicy( QtCore.Qt.ClickFocus )

#self.tabs.append( tab )
name = 'Tab %i'%(self.tabWidget.count()+1) if name is None else name
self.tabWidget.addTab(canvas, name)

return canvas

A basic usage example would be:

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(1, 2*np.pi, 100)
figures = []
for i in range(1,3):
fig, ax = plt.subplots()
y = np.sin(np.pi*i*x)+0.1*np.random.randn(100)
figures.append( fig )

app = qt.QApplication(sys.argv)
ui = MplMultiTab( figures=figures )

Are there any matplotlib ninjas out there who might know how I can get the navigation toolbar to play with the multiple figure canvasses?

Answer Source

I think you can create toolbar for every canvas and show/hide them when tabs.currentTab changed:

class MultiTabNavTool(qt.QWidget):

    def __init__(self, canvases, tabs, parent=None):
        qt.QWidget.__init__(self, parent)
        self.canvases = canvases
        self.tabs = tabs
        self.toolbars = [NavigationToolbar(canvas, parent) for canvas in self.canvases]
        vbox = qt.QVBoxLayout()
        for toolbar in self.toolbars:

    def switch_toolbar(self):
        for toolbar in self.toolbars: