Develop Reference

How to relate QGraphicsScene position to position on a matplotlib plot axis

I have a window which holds two plots, one is a 2D plot and the other is a selection of a cut along the y-axis of that plot. I would like to be able to select what cut I want by moving a horizontal bar up to a position and having the 1D plot update. I am having trouble relating the position from the scene where the line item is, to the axes on the plot. The part where I would be figuring this out is in the main window in the function defined plot_position. I am also open to other ideas of how to go about this. Here is a screen-shot for reference:
import sys
from PyQt5.Qt import Qt, QObject, QPen, QPointF
from PyQt5.QtCore import pyqtSignal
from PyQt5.QtWidgets import QSizePolicy
from PyQt5.QtWidgets import QApplication, QMainWindow, QGraphicsLineItem, QGraphicsView, \
QGraphicsScene, QWidget, QHBoxLayout
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import xarray as xr
import numpy as np
class Signals(QObject):
bttnReleased = pyqtSignal(float, float)
class HLineItem(QGraphicsLineItem):
def __init__(self, signals):
super(HLineItem, self).__init__()
self.signals = signals
self.setPen(QPen(Qt.red, 3))
self.setFlag(QGraphicsLineItem.ItemIsMovable)
self.setCursor(Qt.OpenHandCursor)
self.setAcceptHoverEvents(True)
def mouseMoveEvent(self, event):
orig_cursor_position = event.lastScenePos()
updated_cursor_position = event.scenePos()
orig_position = self.scenePos()
updated_cursor_y = updated_cursor_position.y() - \
orig_cursor_position.y() + orig_position.y()
self.setPos(QPointF(orig_position.x(), updated_cursor_y))
def mouseReleaseEvent(self, event):
x_pos = event.scenePos().x()
y_pos = event.scenePos().y()
self.signals.bttnReleased.emit(x_pos, y_pos)
class PlotCanvas(FigureCanvas):
def __init__(self, parent=None, width=5, height=4, dpi=100):
self.fig = Figure(figsize=(width, height), dpi=dpi)
super(PlotCanvas, self).__init__(self.fig)
self.setParent(parent)
FigureCanvas.setSizePolicy(self,
QSizePolicy.Expanding,
QSizePolicy.Expanding)
FigureCanvas.updateGeometry(self)
self.data = xr.DataArray()
self.axes = None
def plot(self, data):
self.data = data
self.axes = self.fig.add_subplot(111)
self.data.plot(ax=self.axes)
self.axes.set_xlim(-.5, .5)
self.draw()
class MainWindow(QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.signals = Signals()
x = np.linspace(-1, 1, 51)
y = np.linspace(-1, 1, 51)
z = np.linspace(-1, 1, 51)
xyz = np.meshgrid(x, y, z, indexing='ij')
d = np.sin(np.pi * np.exp(-1 * (xyz[0] ** 2 + xyz[1] ** 2 + xyz[2] ** 2))) * np.cos(np.pi / 2 * xyz[1])
self.xar = xr.DataArray(d, coords={"slit": x, 'perp': y, "energy": z}, dims=["slit", "perp", "energy"])
self.cut = self.xar.sel({"perp": 0}, method='nearest')
self.edc = self.cut.sel({'slit': 0}, method='nearest')
self.canvas = PlotCanvas()
self.canvas_edc = PlotCanvas()
self.canvas.plot(self.cut)
self.canvas_edc.plot(self.edc)
self.view = QGraphicsView()
self.scene = QGraphicsScene()
self.line = HLineItem(self.signals)
self.line_pos = [0, 0]
self.layout1 = QHBoxLayout()
self.layout2 = QHBoxLayout()
self.connect_scene()
self.layout1.addWidget(self.view)
self.layout2.addWidget(self.canvas_edc)
self.central = QWidget()
self.main_layout = QHBoxLayout()
self.main_layout.addLayout(self.layout1)
self.main_layout.addLayout(self.layout2)
self.central.setLayout(self.main_layout)
self.setCentralWidget(self.central)
self.signals.bttnReleased.connect(self.plot_position)
def connect_scene(self):
s = self.canvas.figure.get_size_inches() * self.canvas.figure.dpi
self.view.setScene(self.scene)
self.scene.addWidget(self.canvas)
# self.scene.setSceneRect(0, 0, s[0], s[1])
# self.capture_scene_change()
self.line.setLine(0, 0, self.scene.sceneRect().width(), 0)
self.line.setPos(self.line_pos[0], self.line_pos[1])
self.scene.addItem(self.line)
def handle_plotting(self):
self.clearLayout(self.layout2)
self.refresh_edc()
def refresh_edc(self):
self.canvas_edc = PlotCanvas()
self.canvas_edc.plot(self.edc)
self.layout2.addWidget(self.canvas_edc)
def clearLayout(self, layout):
while layout.count():
child = layout.takeAt(0)
if child.widget():
child.widget().deleteLater()
def plot_position(self, x, y):
self.line_pos = [x, y]
plot_bbox = self.canvas.axes.get_position()
# something here to relate the hline position in the scene to the axes positions/plot axes
sel_val = min(self.cut.slit, key=lambda f: abs(f - y)) # this should not be y, but rather
# the corresponding value on the y-axis
self.edc = self.cut.sel({"slit": 0}, method='nearest') # this should not be 0, but rather
# the sel_val
self.handle_plotting()
class App(QApplication):
def __init__(self, sys_argv):
super(App, self).__init__(sys_argv)
self.setAttribute(Qt.AA_EnableHighDpiScaling)
self.mainWindow = MainWindow()
self.mainWindow.setWindowTitle("arpys")
self.mainWindow.show()
def main():
app = App(sys.argv)
sys.exit(app.exec_())
if __name__ == "__main__":
main()

This took me quite a while to figure out. The frustrating part was dealing with Matplotlib's positions of their objects and understanding what classes include what. For a while I was trying to use axes.get_position but this was returning a value for the height that was way too small. I am still not sure for this function what they define as y1 and y0 to give the height. Next I looked at axes.get_window_extent (had a similar problem) and axes.get_tightbbox. the tightbbox function returns the bounding box of the axes including their decorators (xlabel, title, etc) which was better but was actually giving me a height that was beyond the extent I wanted since it included these decorators. Finally, I found that what I really wanted with the length of the spine! In the end I used the spine.get_window_extent() function and this was exactly what I needed. I have attached the updated code.
It was helpful to look at this diagram of the inheritances to see what I was dealing with/looking for.
import sys
from PyQt5.Qt import Qt, QObject, QPen, QPointF
from PyQt5.QtCore import pyqtSignal
from PyQt5.QtWidgets import QSizePolicy
from PyQt5.QtWidgets import QApplication, QMainWindow, QGraphicsLineItem, QGraphicsView, \
QGraphicsScene, QWidget, QHBoxLayout
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import xarray as xr
import numpy as np
class Signals(QObject):
bttnReleased = pyqtSignal(float)
class HLineItem(QGraphicsLineItem):
def __init__(self, signals):
super(HLineItem, self).__init__()
self.signals = signals
self.setPen(QPen(Qt.red, 3))
self.setFlag(QGraphicsLineItem.ItemIsMovable)
self.setCursor(Qt.OpenHandCursor)
self.setAcceptHoverEvents(True)
def mouseMoveEvent(self, event):
orig_cursor_position = event.lastScenePos()
updated_cursor_position = event.scenePos()
orig_position = self.scenePos()
updated_cursor_y = updated_cursor_position.y() - \
orig_cursor_position.y() + orig_position.y()
self.setPos(QPointF(orig_position.x(), updated_cursor_y))
def mouseReleaseEvent(self, event):
y_pos = event.scenePos().y()
self.signals.bttnReleased.emit(y_pos)
class PlotCanvas(FigureCanvas):
def __init__(self, parent=None, width=5, height=4, dpi=100):
self.fig = Figure(figsize=(width, height), dpi=dpi)
super(PlotCanvas, self).__init__(self.fig)
self.setParent(parent)
FigureCanvas.setSizePolicy(self,
QSizePolicy.Expanding,
QSizePolicy.Expanding)
FigureCanvas.updateGeometry(self)
self.data = xr.DataArray()
self.axes = None
def plot(self, data):
self.data = data
self.axes = self.fig.add_subplot(111)
self.data.plot(ax=self.axes)
self.fig.subplots_adjust(left=0.2)
self.fig.subplots_adjust(bottom=0.2)
self.axes.set_xlim(-.5, .5)
self.draw()
class MainWindow(QMainWindow):
def __init__(self):
super(MainWindow, self).__init__()
self.signals = Signals()
x = np.linspace(-1, 1, 51)
y = np.linspace(-1, 1, 51)
z = np.linspace(-1, 1, 51)
xyz = np.meshgrid(x, y, z, indexing='ij')
d = np.sin(np.pi * np.exp(-1 * (xyz[0] ** 2 + xyz[1] ** 2 + xyz[2] ** 2))) * np.cos(np.pi / 2 * xyz[1])
self.xar = xr.DataArray(d, coords={"slit": x, 'perp': y, "energy": z}, dims=["slit", "perp", "energy"])
self.cut = self.xar.sel({"perp": 0}, method='nearest')
self.edc = self.cut.sel({'slit': 0}, method='nearest')
self.canvas = PlotCanvas()
self.canvas_edc = PlotCanvas()
self.canvas.plot(self.cut)
self.canvas_edc.plot(self.edc)
self.view = QGraphicsView()
self.scene = QGraphicsScene()
self.line = HLineItem(self.signals)
self.line_pos = [0, 0]
self.layout1 = QHBoxLayout()
self.layout2 = QHBoxLayout()
self.connect_scene()
self.layout1.addWidget(self.view)
self.layout2.addWidget(self.canvas_edc)
self.central = QWidget()
self.main_layout = QHBoxLayout()
self.main_layout.addLayout(self.layout1)
self.main_layout.addLayout(self.layout2)
self.central.setLayout(self.main_layout)
self.setCentralWidget(self.central)
self.signals.bttnReleased.connect(self.plot_position)
def connect_scene(self):
s = self.canvas.figure.get_size_inches() * self.canvas.figure.dpi
self.view.setScene(self.scene)
self.scene.addWidget(self.canvas)
self.scene.setSceneRect(0, 0, s[0], s[1])
# self.capture_scene_change()
self.line.setLine(0, 0, self.scene.sceneRect().width(), 0)
self.line.setPos(self.line_pos[0], self.line_pos[1])
self.scene.addItem(self.line)
def handle_plotting(self):
self.clearLayout(self.layout2)
self.refresh_edc()
def refresh_edc(self):
self.canvas_edc = PlotCanvas()
self.canvas_edc.plot(self.edc)
self.layout2.addWidget(self.canvas_edc)
def clearLayout(self, layout):
while layout.count():
child = layout.takeAt(0)
if child.widget():
child.widget().deleteLater()
def plot_position(self, y):
rel_pos = lambda x: abs(self.scene.sceneRect().height() - x)
bbox = self.canvas.axes.spines['left'].get_window_extent()
plot_bbox = [bbox.y0, bbox.y1]
if rel_pos(y) < plot_bbox[0]:
self.line.setPos(0, rel_pos(plot_bbox[0]))
elif rel_pos(y) > plot_bbox[1]:
self.line.setPos(0, rel_pos(plot_bbox[1]))
self.line_pos = self.line.pos().y()
size_range = len(self.cut.slit)
r = np.linspace(plot_bbox[0], plot_bbox[1], size_range).tolist()
corr = list(zip(r, self.cut.slit.values))
sel_val = min(r, key=lambda f: abs(f - rel_pos(self.line_pos)))
what_index = r.index(sel_val)
self.edc = self.cut.sel({"slit": corr[what_index][1]}, method='nearest')
self.handle_plotting()
class App(QApplication):
def __init__(self, sys_argv):
super(App, self).__init__(sys_argv)
self.setAttribute(Qt.AA_EnableHighDpiScaling)
self.mainWindow = MainWindow()
self.mainWindow.setWindowTitle("arpys")
self.mainWindow.show()
def main():
app = App(sys.argv)
sys.exit(app.exec_())
if __name__ == "__main__":
main()

How to make matplotlib widget in PyQt5 clickable?

I am working on GUI where I have tab system with graphs. I want that if a user clicks (or puts cursor) at any point in the graph, it shows the exact x and y values in that point like that:
I know that in usual matplotlib it is easy to implement; however I do not know how to do that in PyQt5.
My tabs system and canvas look like that:
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
from PyQt5.QtWidgets import QDialog
from PyQt5.QtWidgets import QApplication, QWidget,QVBoxLayout,QTabWidget
import sys
import matplotlib.pyplot as plt
def mouse_move(event):
x, y = event.xdata, event.ydata
print(x, y)
plt.connect('motion_notify_event', mouse_move)
class Canvas(FigureCanvas):
def __init__(self, parent=None, width=5, height=5, dpi=80):
fig = Figure(figsize=(width, height), dpi=dpi)
self.axes = fig.add_subplot(111)
FigureCanvas.__init__(self, fig)
self.setParent(parent)
self.plot()
def plot(self):
x = ['22-02 11:16:15', '22-02 15:31:54', '22-02 15:32:30',
'22-02 15:32:45', '22-02 15:33:57', '22-02 15:34:13',
'22-02 15:34:46']
y = [1, 4, 3, 4, 8, 9, 2]
self.figure.tight_layout()
ax = self.figure.add_subplot(111)
ax.plot(x, y)
class MainWindow(QDialog):
def __init__(self):
super().__init__()
self.top = 255
self.left = 150
self.setGeometry(self.left, self.top, 900, 900)
self.Mainlayout = QVBoxLayout(self)
self.tabs = QTabWidget()
self.graphUP = QWidget()
self.graphUP.layout = QVBoxLayout( self.graphUP)
self.graphUP.layout.addWidget(Canvas())
self.tabs.setFixedHeight(800)
self.tabs.setFixedWidth(800)
self.tabs.addTab(self.graphUP, "Graph1")
self.Mainlayout.addWidget(self.tabs)
self.show()
if __name__ == '__main__':
App = QApplication(sys.argv)
window = MainWindow()
sys.exit(App.exec())

import this module:
import mplcursors as mpl
and add : mpl.cursor(hover=True)
in your def plot() function.

How to organize layout using PyQt

I'm very new to PyQt and I'm finding ordering the widgets in the window pretty hard.
I have a plot that updates in real-time, a table that updates every time that the user clicks on the plot, and two buttons (start/stop).
The current layout is behaving this way:
I want it to look something like this:
Where "other widgets" correspond to future Widgets I'll add when this is working (such as a slider or a dropdown list). The table should also be as thin as possible, to maximize the size of the plot and don't have the table occupying unnecessary space. My current code is the following one (it's self-contained):
import sys
import numpy as np
from matplotlib.backends.qt_compat import QtWidgets
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.figure import Figure
def onclick(event):
global clicks
clicks.append(event.xdata)
return
class ApplicationWindow(QtWidgets.QMainWindow):
def __init__(self):
super(ApplicationWindow, self).__init__()
self._title = 'Prueba real-time'
self.setWindowTitle(self._title)
self._main = QtWidgets.QWidget()
self.setCentralWidget(self._main)
layout = QtWidgets.QHBoxLayout(self._main)
dynamic_canvas = FigureCanvas(Figure(figsize=(10, 10)))
layout.addWidget(dynamic_canvas)
self._dynamic_ax = dynamic_canvas.figure.subplots()
dynamic_canvas.figure.canvas.mpl_connect('button_press_event', onclick)
self._dynamic_ax.grid()
self._timer = dynamic_canvas.new_timer(
100, [(self._update_window, (), {})])
self._timer.start()
button_stop = QtWidgets.QPushButton('Stop', self)
layout.addWidget(button_stop)
button_stop.clicked.connect(self.button_pressed)
button_start = QtWidgets.QPushButton('Start', self)
layout.addWidget(button_start)
button_start.clicked.connect(self.button_pressed)
self.table_clicks = QtWidgets.QTableWidget()
self.table_clicks.setRowCount(0)
self.table_clicks.setColumnCount(2)
layout.addWidget(self.table_clicks)
def button_pressed(self):
if self.sender().text() == 'Stop':
self._timer.stop()
if self.sender().text() == 'Start':
self._timer.start()
def _update_window(self):
self._dynamic_ax.clear()
global x, y1, y2, y3, N, count_iter, last_number_clicks
x.append(x[count_iter] + 0.01)
y1.append(np.random.random())
idx_inf = max([count_iter-N, 0])
if last_number_clicks < len(clicks):
for new_click in clicks[last_number_clicks:(len(clicks))]:
rowPosition = self.table_clicks.rowCount()
self.table_clicks.insertRow(rowPosition)
self.table_clicks.setItem(rowPosition,0, QtWidgets.QTableWidgetItem(str(new_click)))
self.table_clicks.setItem(rowPosition,1, QtWidgets.QTableWidgetItem("Descripcion"))
last_number_clicks = len(clicks)
self._dynamic_ax.plot(x[idx_inf:count_iter], y1[idx_inf:count_iter],'-o', color='b')
count_iter += 1
self._dynamic_ax.figure.canvas.draw()
#%%
if __name__ == "__main__":
pressed_key = {}
clicks = []
last_number_clicks = len(clicks)
N = 25
y1 = [np.random.random()]
x = [0]
count_iter = 0
qapp = QtWidgets.QApplication(sys.argv)
app = ApplicationWindow()
app.show()
qapp.exec_()

The structure that you want is a grid so you should use a QGridLayout.
QGridLayout has the addWidget() method where you can indicate the row and column where the widget will be placed, the same with addLayout()
void QGridLayout::addWidget(QWidget *widget, int row, int column, Qt::Alignment alignment = ...)
void QGridLayout::addLayout(QLayout *layout, int row, int column, Qt::Alignment alignment = ...)
In your case the structure should be the following:
QGridLayout
├── Plot (0, 0)
├── Table (0, 1)
├── Other Widgets (1, 0)
└── QVBoxLayout (1, 1)
    ├── button_start
   └── button_stop
Then you can indicate the weight of each column, that is, say that the column width will have a proportional width with respect to column 2 using setColumnStretch():
layout.setColumnStretch(0, 2)
layout.setColumnStretch(1, 1)
Considering the above we have the following:
import sys
import numpy as np
from matplotlib.backends.qt_compat import QtCore, QtGui, QtWidgets
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.figure import Figure
def onclick(event):
global clicks
clicks.append(event.xdata)
class ApplicationWindow(QtWidgets.QMainWindow):
def __init__(self):
super(ApplicationWindow, self).__init__()
self._title = 'Prueba real-time'
self.setWindowTitle(self._title)
self._main = QtWidgets.QWidget()
self.setCentralWidget(self._main)
dynamic_canvas = FigureCanvas(Figure(figsize=(10, 10)))
self._dynamic_ax = dynamic_canvas.figure.subplots()
dynamic_canvas.figure.canvas.mpl_connect('button_press_event', onclick)
self._dynamic_ax.grid()
self._timer = dynamic_canvas.new_timer(
100, [(self._update_window, (), {})])
self._timer.start()
button_stop = QtWidgets.QPushButton('Stop', self)
button_stop.clicked.connect(self._timer.stop)
button_start = QtWidgets.QPushButton('Start', self)
button_start.clicked.connect(self._timer.start)
self.table_clicks = QtWidgets.QTableWidget(0, 2)
self.table_clicks.horizontalHeader().setSectionResizeMode(QtWidgets.QHeaderView.Stretch)
other_widget = QtWidgets.QLabel("Other widgets",
font=QtGui.QFont("Times", 60, QtGui.QFont.Bold),
alignment=QtCore.Qt.AlignCenter)
# layouts
layout = QtWidgets.QGridLayout(self._main)
layout.addWidget(dynamic_canvas, 0, 0)
layout.addWidget(self.table_clicks, 0, 1)
layout.addWidget(other_widget, 1, 0)
button_layout = QtWidgets.QVBoxLayout()
button_layout.addWidget(button_stop)
button_layout.addWidget(button_start)
layout.addLayout(button_layout, 1, 1)
layout.setColumnStretch(0, 2)
layout.setColumnStretch(1, 1)
def _update_window(self):
self._dynamic_ax.clear()
global x, y1, y2, y3, N, count_iter, last_number_clicks
x.append(x[count_iter] + 0.01)
y1.append(np.random.random())
idx_inf = max([count_iter-N, 0])
if last_number_clicks < len(clicks):
for new_click in clicks[last_number_clicks:(len(clicks))]:
rowPosition = self.table_clicks.rowCount()
self.table_clicks.insertRow(rowPosition)
self.table_clicks.setItem(rowPosition,0, QtWidgets.QTableWidgetItem(str(new_click)))
self.table_clicks.setItem(rowPosition,1, QtWidgets.QTableWidgetItem("Descripcion"))
last_number_clicks = len(clicks)
self._dynamic_ax.plot(x[idx_inf:count_iter], y1[idx_inf:count_iter],'-o', color='b')
count_iter += 1
self._dynamic_ax.figure.canvas.draw()
#%%
if __name__ == "__main__":
pressed_key = {}
clicks = []
last_number_clicks = len(clicks)
N = 25
y1 = [np.random.random()]
x = [0]
count_iter = 0
qapp = QtWidgets.QApplication(sys.argv)
app = ApplicationWindow()
app.show()
sys.exit(qapp.exec_())

I would personally separate the different parts of the program in their own class and use several vertical and horizontal layouts to position the widgets. This especially helps if you want to add features. Especially for large applications this helps to keep the MainWindow, which always tends to become a mess, to be more simple and easier to understand
import sys
import numpy as np
from matplotlib.backends.qt_compat import QtWidgets
from matplotlib.backends.backend_qt5agg import FigureCanvas
from matplotlib.figure import Figure
def onclick(event):
global clicks
clicks.append(event.xdata)
return
class TableWidget(QtWidgets.QWidget):
def __init__(self,parent,*args,**kwargs):
super().__init__(*args,**kwargs)
self.parent = parent
layout = QtWidgets.QVBoxLayout(self)
self.table_clicks = QtWidgets.QTableWidget()
self.table_clicks.setRowCount(0)
self.table_clicks.setColumnCount(2)
layout.addWidget(self.table_clicks)
button_widget = QtWidgets.QWidget(self)
layout.addWidget(button_widget)
button_layout = QtWidgets.QHBoxLayout(button_widget)
button_stop = QtWidgets.QPushButton('Stop', self)
button_layout.addWidget(button_stop)
button_stop.clicked.connect(self.parent.plot_widget.button_pressed)
button_start = QtWidgets.QPushButton('Start', self)
button_layout.addWidget(button_start)
button_start.clicked.connect(self.parent.plot_widget.button_pressed)
class PlotWidget(QtWidgets.QWidget):
def __init__(self,parent,*args,**kwargs):
super().__init__(parent,*args,**kwargs)
self.parent = parent
layout = QtWidgets.QVBoxLayout(self)
dynamic_canvas = FigureCanvas(Figure(figsize=(10, 10)))
layout.addWidget(dynamic_canvas)
self._dynamic_ax = dynamic_canvas.figure.subplots()
dynamic_canvas.figure.canvas.mpl_connect('button_press_event', onclick)
self._dynamic_ax.grid()
self._timer = dynamic_canvas.new_timer(
100, [(self._update_window, (), {})])
self._timer.start()
def button_pressed(self):
if self.sender().text() == 'Stop':
self._timer.stop()
if self.sender().text() == 'Start':
self._timer.start()
def _update_window(self):
self._dynamic_ax.clear()
global x, y1, y2, y3, N, count_iter, last_number_clicks
x.append(x[count_iter] + 0.01)
y1.append(np.random.random())
idx_inf = max([count_iter-N, 0])
if last_number_clicks < len(clicks):
for new_click in clicks[last_number_clicks:(len(clicks))]:
rowPosition = self.parent.table_widget.table_clicks.rowCount()
self.parent.table_widget.table_clicks.insertRow(rowPosition)
self.parent.table_widget.table_clicks.setItem(rowPosition,0, QtWidgets.QTableWidgetItem(str(new_click)))
self.parent.table_widget.table_clicks.setItem(rowPosition,1, QtWidgets.QTableWidgetItem("Descripcion"))
last_number_clicks = len(clicks)
self._dynamic_ax.plot(x[idx_inf:count_iter], y1[idx_inf:count_iter],'-o', color='b')
count_iter += 1
self._dynamic_ax.figure.canvas.draw()
class ApplicationWindow(QtWidgets.QMainWindow):
def __init__(self):
super(ApplicationWindow, self).__init__()
self._title = 'Prueba real-time'
self.setWindowTitle(self._title)
self._main = QtWidgets.QWidget()
self.setCentralWidget(self._main)
main_layout = QtWidgets.QHBoxLayout(self._main)
self.plot_widget = PlotWidget(self)
main_layout.addWidget(self.plot_widget)
self.table_widget = TableWidget(self)
main_layout.addWidget(self.table_widget)
#%%
if __name__ == "__main__":
pressed_key = {}
clicks = []
last_number_clicks = len(clicks)
N = 25
y1 = [np.random.random()]
x = [0]
count_iter = 0
qapp = QtWidgets.QApplication(sys.argv)
app = ApplicationWindow()
app.show()
qapp.exec_()

matplotlib onPick Event registering twice

As part of a larger project I am updating a graph on matplotlib embedded in Pyqt5. I have an onpick event that adds and removes annotation to a scatter point. After I updated my plot in a fashion similar to below the onPick feature registers twice. There is something underlying that is not getting removed correctly. I was wondering what I might clear, besides the figure, that would correct my issue.
Simple Example Highlighting the issue:
import sys
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
class plot(QWidget):
def __init__(self):
super().__init__()
self.figure = plt.figure()
self.canvas = FigureCanvas(self.figure)
self.Layout = QVBoxLayout()
self.xarray = [1,2,3,4,5,6]
self.yarray = [6,7,5,4,2,1]
update_btn = QPushButton("Update Plot", self)
self.Layout.addWidget(update_btn, 1)
update_btn.clicked.connect(self.updateplot)
self.createplot()
self.setLayout(self.Layout)
def updateplot(self):
self.xarray = [6,7,5,3,2,1]
self.figure.clear()
self.createplot()
def createplot(self):
ax = self.figure.add_subplot(1,1,1)
ax.grid()
val = self.displayval(ax)
self.plot = ax.plot(self.xarray, self.yarray,'o', marker = 'o', c= 'b', picker = 5)[0]
self.Layout.addWidget(self.canvas, 2)
self.canvas.draw()
def displayval(self, ax):
def onPick(event):
print("connecting")
plot = event.artist
xval = plot.get_xdata()
yval = plot.get_ydata()
ind = event.ind
if xval[ind].size > 1 or yval[ind].size > 1: return
xy = (xval[ind][0], yval[ind][0])
ann = ax.annotate('(%f , %f)' % xy, xy= xy)
self.figure.canvas.draw()
self.figure.canvas.mpl_connect('pick_event', onPick)
return onPick
if __name__ == '__main__':
appl = QApplication(sys.argv)
main = plot()
main.show()
sys.exit(appl.exec_())
Note: I have tried updating the axis values with something like
ax.set_xaxis()
However this does not render the data correctly in my program, therefore an alternative answer would be preferred.

Here is a Solution to the issue. Thanks to #ImportanceOfBeingErnest for explaining why the issue was occurring. From there I was able to fix the problem. Once updated the on click annotation only occurs once. The solution is only to call displayval once and change ax to 'self.ax' and update the object variable.
import sys
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from PyQt5.QtCore import *
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt5agg import NavigationToolbar2QT as NavigationToolbar
from mpl_toolkits.mplot3d import Axes3D
import matplotlib.pyplot as plt
class plot(QWidget):
def __init__(self):
super().__init__()
self.figure = plt.figure()
self.canvas = FigureCanvas(self.figure)
self.Layout = QVBoxLayout()
self.xarray = [1,2,3,4,5,6]
self.yarray = [6,7,5,4,2,1]
self.init_trigger = True
update_btn = QPushButton("Update Plot", self)
self.Layout.addWidget(update_btn, 1)
update_btn.clicked.connect(self.updateplot)
self.createplot()
self.setLayout(self.Layout)
def updateplot(self):
self.xarray = [6,7,5,3,2,1]
self.figure.clear()
self.createplot()
def createplot(self):
self.ax = self.figure.add_subplot(1,1,1)
self.ax.grid()
if self.init_trigger: val = self.displayval()
self.plot = self.ax.plot(self.xarray, self.yarray,'o', marker = 'o', c= 'b', picker = 5)[0]
self.Layout.addWidget(self.canvas, 2)
self.canvas.draw()
self.init_trigger = False
def displayval(self):
def onPick(event):
print("connecting")
plot = event.artist
xval = plot.get_xdata()
yval = plot.get_ydata()
ind = event.ind
if xval[ind].size > 1 or yval[ind].size > 1: return
xy = (xval[ind][0], yval[ind][0])
ann = self.ax.annotate('(%f , %f)' % xy, xy= xy)
self.figure.canvas.draw()
self.figure.canvas.mpl_connect('pick_event', onPick)
return onPick
if __name__ == '__main__':
appl = QApplication(sys.argv)
main = plot()
main.show()
sys.exit(appl.exec_())

Embed Matplotlib in PyQt with multiple plot

everyone! I want to embed my data into Gui. Here I created 2 Plot button so that I showed my data one by one.Plot1 contained 2 subplot, Plot2 contained 1 plot.
But when I clicked Plot1 and then clicked Plot2, I can't see my data in Plot2, It looks like coordinate doesn't change. How should I fix this?
import matplotlib.pyplot as plt
import numpy as np
import sys
from PyQt4 import QtGui
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QT as NavigationToolbar
class PrettyWidget(QtGui.QWidget):
def __init__(self):
super(PrettyWidget, self).__init__()
self.initUI()
def initUI(self):
self.setGeometry(100,100,800,600)
self.center()
self.setWindowTitle('S Plot')
grid = QtGui.QGridLayout()
self.setLayout(grid)
btn1 = QtGui.QPushButton('Plot 1 ',self)
btn1.resize(btn1.sizeHint())
btn1.clicked.connect(self.plot1)
grid.addWidget(btn1,5,0)
btn2 = QtGui.QPushButton('Plot 2 ',self)
btn2.resize(btn2.sizeHint())
btn2.clicked.connect(self.plot2)
grid.addWidget(btn2,5,1)
self.figure = plt.figure(figsize = (15,5))
self.canvas = FigureCanvas(self.figure)
self.toolbar = NavigationToolbar(self.canvas, self)
grid.addWidget(self.canvas, 3,0,1,2)
grid.addWidget(self.canvas, 3,0,1,2)
self.show()
def plot1(self):
plt.cla()
ax1 = self.figure.add_subplot(211)
x1 = [i for i in range(100)]
y1 = [i**0.5 for i in x1]
ax1.plot(x1,y1,'b.-')
ax2 = self.figure.add_subplot(212)
x2 = [i for i in range(100)]
y2 = [i for i in x2]
ax2.plot(x2,y2,'b.-')
self.canvas.draw()
def plot2(self):
plt.cla()
ax3 = self.figure.add_subplot(111)
x = [i for i in range(100)]
y = [i**0.5 for i in x]
ax3.plot(x,y,'r.-')
ax3.set_title('Square Root Plot')
self.canvas.draw()
def center(self):
qr = self.frameGeometry()
cp = QtGui.QDesktopWidget().availableGeometry().center()
qr.moveCenter(cp)
self.move(qr.topLeft())
app = QtGui.QApplication(sys.argv)
app.aboutToQuit.connect(app.deleteLater)
GUI = PrettyWidget()
sys.exit(app.exec_())

I strongly advise against using pyplot whe doing embedding, the global state management and the FigureManager classes will get in your way.
import sys
from PyQt4 import QtGui
import matplotlib
import matplotlib.figure
from matplotlib.backends.backend_qt4agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt4agg import NavigationToolbar2QT as NavigationToolbar
class PrettyWidget(QtGui.QWidget):
def __init__(self):
super(PrettyWidget, self).__init__()
self.initUI()
def initUI(self):
self.setGeometry(100, 100, 800, 600)
self.center()
self.setWindowTitle('S Plot')
grid = QtGui.QGridLayout()
self.setLayout(grid)
btn1 = QtGui.QPushButton('Plot 1 ', self)
btn1.resize(btn1.sizeHint())
btn1.clicked.connect(self.plot1)
grid.addWidget(btn1, 5, 0)
btn2 = QtGui.QPushButton('Plot 2 ', self)
btn2.resize(btn2.sizeHint())
btn2.clicked.connect(self.plot2)
grid.addWidget(btn2, 5, 1)
self.figure = matplotlib.figure.Figure()
self.canvas = FigureCanvas(self.figure)
self.toolbar = NavigationToolbar(self.canvas, self)
grid.addWidget(self.canvas, 3, 0, 1, 2)
# grid.addWidget(self.toolbar, ??)
self.show()
def plot1(self):
self.figure.clf()
ax1 = self.figure.add_subplot(211)
x1 = [i for i in range(100)]
y1 = [i**0.5 for i in x1]
ax1.plot(x1, y1, 'b.-')
ax2 = self.figure.add_subplot(212)
x2 = [i for i in range(100)]
y2 = [i for i in x2]
ax2.plot(x2, y2, 'b.-')
self.canvas.draw_idle()
def plot2(self):
self.figure.clf()
ax3 = self.figure.add_subplot(111)
x = [i for i in range(100)]
y = [i**0.5 for i in x]
ax3.plot(x, y, 'r.-')
ax3.set_title('Square Root Plot')
self.canvas.draw_idle()
def center(self):
qr = self.frameGeometry()
cp = QtGui.QDesktopWidget().availableGeometry().center()
qr.moveCenter(cp)
self.move(qr.topLeft())
app = QtGui.QApplication(sys.argv)
app.aboutToQuit.connect(app.deleteLater)
GUI = PrettyWidget()
sys.exit(app.exec_())