key_press_event in pyqt4 embedded matplotlib

[psaurav]

Matplotlib does not respond to key presses while embedded in PyQt4. I have verified that key presses work with Tkinter. My system: Matplotlib 1.1.0, python 2.6.5 on Ubuntu. The code I have used is given below:

--code begins--
import sys
import numpy as np
from matplotlib.figure import Figure

from PyQt4.QtCore import *
from PyQt4.QtGui import *

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

class AppForm(QMainWindow):
def init(self, parent=None):
QMainWindow.init(self, parent)
#self.x, self.y = self.get_data()
self.data = self.get_data2()
self.create_main_frame()
self.on_draw()

def create_main_frame(self):
    self.main_frame = QWidget()

    self.fig = Figure((5.0, 4.0), dpi=100)
    self.canvas = FigureCanvas(self.fig)
    self.canvas.setParent(self.main_frame)
    self.mpl_toolbar = NavigationToolbar(self.canvas, self.main_frame)

    self.canvas.mpl_connect('key_press_event', self.on_key_press)

    vbox = QVBoxLayout()
    vbox.addWidget(self.canvas)         # the matplotlib canvas
    vbox.addWidget(self.mpl_toolbar)
    self.main_frame.setLayout(vbox)
    self.setCentralWidget(self.main_frame)

def get_data2(self):
    return np.arange(20).reshape([4,5]).copy()

def on_draw(self):
    self.fig.clear()
    self.axes = self.fig.add_subplot(111)
    #self.axes.plot(self.x, self.y, 'ro')
    self.axes.imshow(self.data, interpolation='nearest')
    self.canvas.draw()

def on_key_press(self, event):
    print 'you pressed', event.key

def main():
app = QApplication(sys.argv)
form = AppForm()
form.show()
app.exec_()

if name == "main":
main()
--code ends--

[psaurav]

I am resubmitting the code --- this time properly formatted.

import sys
import numpy as np
from matplotlib.figure import Figure

from PyQt4.QtCore import *
from PyQt4.QtGui import *

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


class AppForm(QMainWindow):
    def __init__(self, parent=None):
        QMainWindow.__init__(self, parent)
        #self.x, self.y = self.get_data()
        self.data = self.get_data2()
        self.create_main_frame()
        self.on_draw()

    def create_main_frame(self):
        self.main_frame = QWidget()

        self.fig = Figure((5.0, 4.0), dpi=100)
        self.canvas = FigureCanvas(self.fig)
        self.canvas.setParent(self.main_frame)
        self.mpl_toolbar = NavigationToolbar(self.canvas, self.main_frame)

        self.canvas.mpl_connect('key_press_event', self.on_key_press)

        vbox = QVBoxLayout()
        vbox.addWidget(self.canvas)         # the matplotlib canvas
        vbox.addWidget(self.mpl_toolbar)
        self.main_frame.setLayout(vbox)
        self.setCentralWidget(self.main_frame)

    def get_data2(self):
        return np.arange(20).reshape([4,5]).copy()

    def on_draw(self):
        self.fig.clear()
        self.axes = self.fig.add_subplot(111)
        #self.axes.plot(self.x, self.y, 'ro')
        self.axes.imshow(self.data, interpolation='nearest')
        self.canvas.draw()

    def on_key_press(self, event):
        print 'you pressed', event.key


def main():
    app = QApplication(sys.argv)
    form = AppForm()
    form.show()
    app.exec_()

if __name__ == "__main__":
    main()

[WeatherGod]

This might be related to issue 525

[jdh2358]

You need to activate the focus of qt onto your mpl canvas.

Just add:

self.canvas.setFocusPolicy( Qt.ClickFocus )
self.canvas.setFocus()

right after you call setParent.

Also, I just submitted a pull request #717 which exposes to embedding applications the default mpl keypress handler described at http://matplotlib.sourceforge.net/users/navigation_toolbar.html#navigation-keyboard-shortcuts. I modified your example to use this handler and submitted it as an example: https://github.com/jdh2358/matplotlib/blob/00824666129917301b21404b364879cd4b732495/examples/user_interfaces/embedding_in_qt4_wtoolbar.py

[pelson]

@jdh2358 has provided a solution for this issue. closing.