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I want to add a cross hair that snaps to data points and be updated on mouse move. I found this example that works well:
import numpy as np
import matplotlib.pyplot as plt
class SnappingCursor:
"""
A cross hair cursor that snaps to the data point of a line, which is
closest to the *x* position of the cursor.
For simplicity, this assumes that *x* values of the data are sorted.
"""
def __init__(self, ax, line):
self.ax = ax
self.horizontal_line = ax.axhline(color='k', lw=0.8, ls='--')
self.vertical_line = ax.axvline(color='k', lw=0.8, ls='--')
self.x, self.y = line.get_data()
self._last_index = None
# text location in axes coords
self.text = ax.text(0.72, 0.9, '', transform=ax.transAxes)
def set_cross_hair_visible(self, visible):
need_redraw = self.vertical_line.get_visible() != visible
self.vertical_line.set_visible(visible)
self.horizontal_line.set_visible(visible)
self.text.set_visible(visible)
return need_redraw
def on_mouse_move(self, event):
if not event.inaxes:
self._last_index = None
need_redraw = self.set_cross_hair_visible(False)
if need_redraw:
self.ax.figure.canvas.draw()
else:
self.set_cross_hair_visible(True)
x, y = event.xdata, event.ydata
index = min(np.searchsorted(self.y, y), len(self.y) - 1)
if index == self._last_index:
return # still on the same data point. Nothing to do.
self._last_index = index
x = self.x[index]
y = self.y[index]
# update the line positions
self.horizontal_line.set_ydata(y)
self.vertical_line.set_xdata(x)
self.text.set_text('x=%1.2f, y=%1.2f' % (x, y))
self.ax.figure.canvas.draw()
y = np.arange(0, 1, 0.01)
x = np.sin(2 * 2 * np.pi * y)
fig, ax = plt.subplots()
ax.set_title('Snapping cursor')
line, = ax.plot(x, y, 'o')
snap_cursor = SnappingCursor(ax, line)
fig.canvas.mpl_connect('motion_notify_event', snap_cursor.on_mouse_move)
plt.show()
But I get into trouble when I want to adapt the code with the PyQt5 and show the plot in a GUI. My code is:
from PyQt5.QtWidgets import QApplication, QMainWindow, QWidget, QVBoxLayout
import sys
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
import numpy as np
class SnappingCursor:
"""
A cross hair cursor that snaps to the data point of a line, which is
closest to the *x* position of the cursor.
For simplicity, this assumes that *x* values of the data are sorted.
"""
def __init__(self, ax, line):
self.ax = ax
self.horizontal_line = ax.axhline(color='k', lw=0.8, ls='--')
self.vertical_line = ax.axvline(color='k', lw=0.8, ls='--')
self.x, self.y = line.get_data()
self._last_index = None
# text location in axes coords
self.text = ax.text(0.72, 0.9, '', transform=ax.transAxes)
def set_cross_hair_visible(self, visible):
need_redraw = self.vertical_line.get_visible() != visible
self.vertical_line.set_visible(visible)
self.horizontal_line.set_visible(visible)
self.text.set_visible(visible)
return need_redraw
def on_mouse_move(self, event):
if not event.inaxes:
self._last_index = None
need_redraw = self.set_cross_hair_visible(False)
if need_redraw:
self.ax.figure.canvas.draw()
else:
self.set_cross_hair_visible(True)
x, y = event.xdata, event.ydata
index = min(np.searchsorted(self.y, y), len(self.y) - 1)
if index == self._last_index:
return # still on the same data point. Nothing to do.
self._last_index = index
x = self.x[index]
y = self.y[index]
# update the line positions
self.horizontal_line.set_ydata(y)
self.vertical_line.set_xdata(x)
self.text.set_text('x=%1.2f, y=%1.2f' % (x, y))
self.ax.figure.canvas.draw()
class Window(QMainWindow):
def __init__(self):
super().__init__()
widget=QWidget()
vbox=QVBoxLayout()
plot1 = FigureCanvas(Figure(tight_layout=True, linewidth=3))
ax = plot1.figure.subplots()
x = np.arange(0, 1, 0.01)
y = np.sin(2 * 2 * np.pi * x)
line, = ax.plot(x, y, 'o')
snap_cursor = SnappingCursor(ax, line)
plot1.mpl_connect('motion_notify_event', snap_cursor.on_mouse_move)
vbox.addWidget(plot1)
widget.setLayout(vbox)
self.setCentralWidget(widget)
self.setWindowTitle('Example')
self.show()
App = QApplication(sys.argv)
window = Window()
sys.exit(App.exec())
By running the above code, the data is plotted properly, but the cross hair is only shown in its initial position and does not move by mouse movement. Data values are also not displayed.
I have found a similar question here too, but the question is not answered clearly.
There are 2 problems:
snap_cursor is a local variable that will be removed when __init__ finishes executing. You must make him a member of the class.
The initial code of the tutorial is designed so that the point that information is displayed is the horizontal line that passes through the cursor and intersects the curve. In your initial code it differs from the example and also does not work for your new curve so I restored the logic of the tutorial.
import sys
from PyQt5.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QWidget
import numpy as np
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.figure import Figure
class SnappingCursor:
"""
A cross hair cursor that snaps to the data point of a line, which is
closest to the *x* position of the cursor.
For simplicity, this assumes that *x* values of the data are sorted.
"""
def __init__(self, ax, line):
self.ax = ax
self.horizontal_line = ax.axhline(color="k", lw=0.8, ls="--")
self.vertical_line = ax.axvline(color="k", lw=0.8, ls="--")
self.x, self.y = line.get_data()
self._last_index = None
# text location in axes coords
self.text = ax.text(0.72, 0.9, "", transform=ax.transAxes)
def set_cross_hair_visible(self, visible):
need_redraw = self.vertical_line.get_visible() != visible
self.vertical_line.set_visible(visible)
self.horizontal_line.set_visible(visible)
self.text.set_visible(visible)
return need_redraw
def on_mouse_move(self, event):
if not event.inaxes:
self._last_index = None
need_redraw = self.set_cross_hair_visible(False)
if need_redraw:
self.ax.figure.canvas.draw()
else:
self.set_cross_hair_visible(True)
x, y = event.xdata, event.ydata
index = min(np.searchsorted(self.x, x), len(self.x) - 1)
if index == self._last_index:
return # still on the same data point. Nothing to do.
self._last_index = index
x = self.x[index]
y = self.y[index]
# update the line positions
self.horizontal_line.set_ydata(y)
self.vertical_line.set_xdata(x)
self.text.set_text("x=%1.2f, y=%1.2f" % (x, y))
self.ax.figure.canvas.draw()
class Window(QMainWindow):
def __init__(self):
super().__init__()
widget = QWidget()
vbox = QVBoxLayout(widget)
x = np.arange(0, 1, 0.01)
y = np.sin(2 * 2 * np.pi * x)
canvas = FigureCanvas(Figure(tight_layout=True, linewidth=3))
ax = canvas.figure.subplots()
ax.set_title("Snapping cursor")
(line,) = ax.plot(x, y, "o")
self.snap_cursor = SnappingCursor(ax, line)
canvas.mpl_connect("motion_notify_event", self.snap_cursor.on_mouse_move)
vbox.addWidget(canvas)
self.setCentralWidget(widget)
self.setWindowTitle("Example")
app = QApplication(sys.argv)
w = Window()
w.show()
app.exec()
Problem description:
I'm building an interface for my lab, I intergrarted matplotlib with pyqt5 widget, there is a real time video display widget working on multi-thread and queue. I managed to show single shot with cross-section plot by adding divider. However, when I remove the cross-section plots, and redraw the figure_idle, the video frame can never moved back to its initial position with its initial size. I adjust the figure with navigator_tool_bar (top, bottom...), However it seems that there are blank areas left after removing the cross-section plots. Do you have any idea?
The initial figure:
Display cross-sections:
Clear cross-section and redraw:
Video widget code:
class VideoViewer(FigureCanvas):
def __init__(self, parent=None, width=4, height=4, dpi=70):
self.figwidth = width
self.figheight = height
self.fig = Figure(figsize=(self.figwidth, self.figheight), dpi=dpi)
FigureCanvas.__init__(self, self.fig)
FigureCanvas.setSizePolicy(self, QSizePolicy.Expanding, QSizePolicy.Expanding)
FigureCanvas.updateGeometry(self)
self.axes = self.fig.add_subplot()
self.fig.subplots_adjust(top=0.975,bottom=0.048,left=0.029,right=0.983,hspace=0.2,wspace=0.2)
Cross section code:
#create cross-sections
self.divider = make_axes_locatable(self.axes)
self.top_ax = self.divider.append_axes("top", 1.05, pad=0.2,sharex=self.axes)
self.right_ax = self.divider.append_axes("right", 1.05,pad=0.2,sharey=self.axes)
#create lines
self.v_line = self.axes.axvline(xvlinepos, color='r')
self.h_line = self.axes.axhline(yhlinepos, color='g')
self.v_cross, = self.right_ax.plot(Norm_xvlinedata,np.arange(self.ImageData.shape[0]), 'r-')
self.h_cross, = self.top_ax.plot(np.arange(self.ImageData.shape[1]),Norm_yhlinedata, 'g-')
Clear cross-section code:
def ClearCrossSection(self):
self.fig.canvas.mpl_disconnect(self.pick_event_v)
self.fig.canvas.mpl_disconnect(self.pick_event_h)
self.h_line.remove()
self.v_line.remove()
self.v_cross.remove()
self.h_cross.remove()
self.right_ax.remove()
self.top_ax.remove()
self.fig.canvas.draw_idle()
What I did:
Light_layout + subplot_adjust -----> does not work.
Constrained_layout -----> does not work.
Constrained_layout + GridSpec by declaring at beginning self.axes takes all cols and rows.-----> Does not work.
An exemple of the problem:
import sys
# GUI
from PyQt5.QtWidgets import*
from PyQt5.QtCore import *
from PyQt5.QtGui import *
# Matplotlib
import matplotlib
matplotlib.use('Qt5Agg')
import matplotlib.pyplot as plt
from matplotlib.figure import Figure
import matplotlib.gridspec as gridspec
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
from matplotlib.backends.backend_qt5 import NavigationToolbar2QT as NavigationToolbar
from mpl_toolkits.axes_grid1 import make_axes_locatable
from PIL import Image
import matplotlib.lines as lines
# Generate data
import numpy as np
'''
need to update video frame, I'm using blitting, so better not clear the whole figure.
the whole code could be too long to show here.
'''
class Window(QMainWindow):
def __init__(self):
super(Window, self).__init__()
self.resize(800,600)
self.setGeometry(350,250,950,600)
# Creat MainWidget
self.MainWidget = QWidget()
self.LayoutMainWidget = QGridLayout()
self.MainWidget.setLayout(self.LayoutMainWidget)
# Matplotlib widget
self.MatplotViewer = VideoViewer()
self.FigureTool = NavigationToolbar(self.MatplotViewer, self)
# Button plot image
self.ButtPltImg = QPushButton("Plot Image")
# BUtton plot cross
self.ButtPltCross = QPushButton("Cross View")
self.ButtPltCross.setCheckable(True)
self.ButtPltCross.setStyleSheet("background-color: Green")
# add widgets
self.LayoutMainWidget.addWidget(self.MatplotViewer,0,0,7,7)
self.LayoutMainWidget.addWidget(self.FigureTool, 7,0,1,7)
self.LayoutMainWidget.addWidget(self.ButtPltImg, 2,7,1,1)
self.LayoutMainWidget.addWidget(self.ButtPltCross, 3,7,1,1)
# Set central widget
self.setCentralWidget(self.MainWidget)
self.connection()
def GenerateImage(self, state):
if self.ButtPltCross.isChecked():
self.ButtPltCross.setChecked(False)
self.MatplotViewer.ClearCrossSection()
self.MatplotViewer.UpdateFrame()
else:
self.MatplotViewer.UpdateFrame()
def PlotCrossSection(self, state):
if self.ButtPltCross.isChecked():
self.MatplotViewer.PlotCrossSection()
def ClearCrossSection(self, state):
if not(self.ButtPltCross.isChecked()):
self.MatplotViewer.ClearCrossSection()
def connection(self):
self.ButtPltImg.clicked.connect(lambda state=True: self.GenerateImage(state))
self.ButtPltCross.clicked.connect(lambda state=True: self.PlotCrossSection(state))
self.ButtPltCross.clicked.connect(lambda state=True: self.ClearCrossSection(state))
class VideoViewer(FigureCanvas):
def __init__(self, parent=None, width=4, height=4, dpi=70):
# Figure
self.fig = Figure(figsize=(width, height), dpi=dpi)
# Init Parent
FigureCanvas.__init__(self, self.fig)
FigureCanvas.setSizePolicy(self, QSizePolicy.Expanding, QSizePolicy.Expanding)
FigureCanvas.updateGeometry(self)
# Ax
self.axes = self.fig.add_subplot(111)
self.fig.subplots_adjust(top=0.975,bottom=0.048,left=0.029,right=0.983,hspace=0.2,wspace=0.2)
# Plot init image
self.PlotInitFrame()
def PlotInitFrame(self):
self.ImageData = self.ImageGenerate()
self.image = self.axes.imshow(self.ImageData, cmap='Greys', interpolation='none')
self.fig.canvas.draw_idle()
def UpdateFrame(self):
self.ImageData = self.ImageGenerate()
self.image.set_data(self.ImageData)
self.fig.canvas.draw_idle()
def PlotCrossSection(self):
# create axes
self.divider = make_axes_locatable(self.axes)
self.top_ax = self.divider.append_axes("top", 1.05, pad=0.2,sharex=self.axes)
self.right_ax = self.divider.append_axes("right", 1.05, pad=0.2,sharey=self.axes)
self.top_ax.xaxis.set_tick_params(labelbottom=False)
self.right_ax.yaxis.set_tick_params(labelleft=False)
# set cross section limit
self.right_ax.set_xlim(right=1.05)
self.top_ax.set_ylim(top=1.05)
# some pars
xmin, xmax = self.axes.get_xlim()
ymin, ymax = self.axes.get_ylim()
v_mid = int((xmin + xmax)/2)
h_mid = int((ymin + ymax)/2)
# set line
self.v_line = lines.Line2D([v_mid, v_mid], [ymin, ymax], color='r', pickradius=5)
self.axes.add_line(self.v_line)
self.h_line = lines.Line2D([xmin, xmax], [h_mid, h_mid], color='g', pickradius=5)
self.axes.add_line(self.h_line)
# set cross section data
Norm_xvlinedata = self.NormalizeData(self.ImageData[:,v_mid])
self.v_cross, = self.right_ax.plot(Norm_xvlinedata, np.arange(self.ImageData.shape[0]), 'r-')
Norm_yhlinedata = self.NormalizeData(self.ImageData[h_mid,:])
self.h_cross, = self.top_ax.plot(np.arange(self.ImageData.shape[1]), Norm_yhlinedata, 'g-')
self.fig.canvas.draw_idle()
def NormalizeData(self, data_temp):
min_temp = np.min(data_temp)
max_temp = np.max(data_temp)
if min_temp != max_temp:
return (data_temp-min_temp)/(max_temp-min_temp)
else:
return data_temp/data_temp
def ClearCrossSection(self):
self.v_line.remove()
self.h_line.remove()
self.top_ax.remove()
self.right_ax.remove()
self.fig.canvas.draw_idle()
def ImageGenerate(self):
xx,yy = np.meshgrid(np.linspace(-502,502,1024),np.linspace(-502,502,1024))
r = np.sqrt(xx**2+yy**2)
AMP = np.random.randint(150,250)
SIG = np.random.randint(200,250)
T = np.random.randint(115,135)
return AMP*np.exp(-(r)**2/(2*SIG**2))*np.cos(2*np.pi/T*r)
if __name__ == '__main__':
app = QApplication(sys.argv)
MainWindow = Window()
MainWindow.showMaximized()
sys.exit(app.exec_())
I am using matplotlib figure embedded in pyqt5 to draw a frame taking the height and the width from line edit entries.It works well but when I change the values inside the line edits and click on the push button it will draw another frame over the previous one. I have tried plt.gcf().clear() and ax.clear and they did not work.
class Window(QMainWindow):
def __init__(self):
super().__init__()
self.setWindowTitle("Draw Frame")
self.setGeometry(100,100,680, 450)
# Creation of figure and canvas
self.figure = plt.figure()
self.canvas = FigureCanvas(self.figure)
self.ax = self.figure.add_subplot(111)
self.ax.axis("off")
#self.toolbar = NavigationToolbar(self.canvas, self)
self.plot_widget = QWidget(self)
self.plot_widget.setGeometry(250, 10, 400, 400)
plot_box = QVBoxLayout()
plot_box.addWidget(self.canvas)
self.plot_widget.setLayout(plot_box)
self.label1=QLabel("Frame height",self)
self.label1.move(10,30)
self.label2 = QLabel("Frame height", self)
self.label2.move(10, 70)
self.lineEdit1=QLineEdit(self)
self.lineEdit1.move(100,30)
self.lineEdit1.setText("10")
self.lineEdit2 = QLineEdit(self)
self.lineEdit2.move(100, 70)
self.lineEdit2.setText("20")
self.button = QPushButton('Draw Frame', self)
self.button.clicked.connect(self.plot)
self.button.move(70, 350)
self.show()
def plot(self):
if len(self.lineEdit1.text())!=0:
self.h=int(self.lineEdit1.text())
else:
self.h=0
if len(self.lineEdit2.text()) != 0:
self.w=int(self.lineEdit2.text())
else:
self.w=0
x = [0, 0, self.w, self.w]
y = [0, self.h, self.h, 0]
self.ax.plot(x, y)
self.canvas.draw()
Picture of the app
Instead of clearing the axes you may update the line that is drawn with the new coordinates.
from PyQt5.QtWidgets import *
import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
import sys
class Window(QMainWindow):
def __init__(self):
super().__init__()
self.setWindowTitle("Draw Frame")
self.setGeometry(100,100,680, 450)
# Creation of figure and canvas
self.figure = plt.figure()
self.canvas = FigureCanvas(self.figure)
self.ax = self.figure.add_subplot(111)
self.ax.axis("off")
self.line, = self.ax.plot([])
self.ax.axis([0,100,0,100])
#self.toolbar = NavigationToolbar(self.canvas, self)
self.plot_widget = QWidget(self)
self.plot_widget.setGeometry(250, 10, 400, 400)
plot_box = QVBoxLayout()
plot_box.addWidget(self.canvas)
self.plot_widget.setLayout(plot_box)
self.label1=QLabel("Frame height",self)
self.label1.move(10,30)
self.label2 = QLabel("Frame height", self)
self.label2.move(10, 70)
self.lineEdit1=QLineEdit(self)
self.lineEdit1.move(100,30)
self.lineEdit1.setText("10")
self.lineEdit2 = QLineEdit(self)
self.lineEdit2.move(100, 70)
self.lineEdit2.setText("20")
self.button = QPushButton('Draw Frame', self)
self.button.clicked.connect(self.plot)
self.button.move(70, 350)
self.show()
def plot(self):
if len(self.lineEdit1.text())!=0:
self.h=int(self.lineEdit1.text())
else:
self.h=0
if len(self.lineEdit2.text()) != 0:
self.w=int(self.lineEdit2.text())
else:
self.w=0
x = [0, 0, self.w, self.w]
y = [0, self.h, self.h, 0]
self.line.set_data(x,y)
self.canvas.draw()
if __name__=='__main__':
app = QApplication(sys.argv)
w = Window()
app.exec_()
As mentioned in the comment above, you need to call self.ax.clear() every time you click the button. Otherwise you will be redrawing on the same plot. Not sure why your graph doesnt reset on clear(), but here is the code I ran which worked fine. Let me know if it works for you:
from PyQt5.QtWidgets import *
import matplotlib.pyplot as plt
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
import sys
class Window(QMainWindow):
def __init__(self):
super().__init__()
self.setWindowTitle("Draw Frame")
self.setGeometry(100,100,680, 450)
# Creation of figure and canvas
self.figure = plt.figure()
self.canvas = FigureCanvas(self.figure)
self.ax = self.figure.add_subplot(111)
self.ax.axis("off")
#self.toolbar = NavigationToolbar(self.canvas, self)
self.plot_widget = QWidget(self)
self.plot_widget.setGeometry(250, 10, 400, 400)
plot_box = QVBoxLayout()
plot_box.addWidget(self.canvas)
self.plot_widget.setLayout(plot_box)
self.label1=QLabel("Frame height",self)
self.label1.move(10,30)
self.label2 = QLabel("Frame height", self)
self.label2.move(10, 70)
self.lineEdit1=QLineEdit(self)
self.lineEdit1.move(100,30)
self.lineEdit1.setText("10")
self.lineEdit2 = QLineEdit(self)
self.lineEdit2.move(100, 70)
self.lineEdit2.setText("20")
self.button = QPushButton('Draw Frame', self)
self.button.clicked.connect(self.plot)
self.button.move(70, 350)
self.show()
def plot(self):
self.ax.clear()
if len(self.lineEdit1.text())!=0:
self.h=int(self.lineEdit1.text())
else:
self.h=0
if len(self.lineEdit2.text()) != 0:
self.w=int(self.lineEdit2.text())
else:
self.w=0
x = [0, 0, self.w, self.w]
y = [0, self.h, self.h, 0]
self.ax.plot(x, y)
self.canvas.draw()
if __name__=='__main__':
app = QApplication(sys.argv)
w = Window()
app.exec_()
I have a plot from matplotlib for which I would like to display labels on the marker points when hover over with the mouse.
I found this very helpful working example on SO and I was trying to integrate the exact same plot into a pyqt5 application.
Unfortunately when having the plot in the application the hovering doesn't work anymore.
Here is a full working example based on the mentioned SO post:
import matplotlib.pyplot as plt
import scipy.spatial as spatial
import numpy as np
from PyQt5.QtCore import *
from PyQt5.QtGui import *
from PyQt5.QtWidgets import *
from matplotlib.backends.backend_qt5agg import FigureCanvasQTAgg as FigureCanvas
import sys
pi = np.pi
cos = np.cos
def fmt(x, y):
return 'x: {x:0.2f}\ny: {y:0.2f}'.format(x=x, y=y)
class FollowDotCursor(object):
"""Display the x,y location of the nearest data point.
https://stackoverflow.com/a/4674445/190597 (Joe Kington)
https://stackoverflow.com/a/13306887/190597 (unutbu)
https://stackoverflow.com/a/15454427/190597 (unutbu)
"""
def __init__(self, ax, x, y, tolerance=5, formatter=fmt, offsets=(-20, 20)):
try:
x = np.asarray(x, dtype='float')
except (TypeError, ValueError):
x = np.asarray(mdates.date2num(x), dtype='float')
y = np.asarray(y, dtype='float')
mask = ~(np.isnan(x) | np.isnan(y))
x = x[mask]
y = y[mask]
self._points = np.column_stack((x, y))
self.offsets = offsets
y = y[np.abs(y-y.mean()) <= 3*y.std()]
self.scale = x.ptp()
self.scale = y.ptp() / self.scale if self.scale else 1
self.tree = spatial.cKDTree(self.scaled(self._points))
self.formatter = formatter
self.tolerance = tolerance
self.ax = ax
self.fig = ax.figure
self.ax.xaxis.set_label_position('top')
self.dot = ax.scatter(
[x.min()], [y.min()], s=130, color='green', alpha=0.7)
self.annotation = self.setup_annotation()
plt.connect('motion_notify_event', self)
def scaled(self, points):
points = np.asarray(points)
return points * (self.scale, 1)
def __call__(self, event):
ax = self.ax
# event.inaxes is always the current axis. If you use twinx, ax could be
# a different axis.
if event.inaxes == ax:
x, y = event.xdata, event.ydata
elif event.inaxes is None:
return
else:
inv = ax.transData.inverted()
x, y = inv.transform([(event.x, event.y)]).ravel()
annotation = self.annotation
x, y = self.snap(x, y)
annotation.xy = x, y
annotation.set_text(self.formatter(x, y))
self.dot.set_offsets((x, y))
bbox = ax.viewLim
event.canvas.draw()
def setup_annotation(self):
"""Draw and hide the annotation box."""
annotation = self.ax.annotate(
'', xy=(0, 0), ha = 'right',
xytext = self.offsets, textcoords = 'offset points', va = 'bottom',
bbox = dict(
boxstyle='round,pad=0.5', fc='yellow', alpha=0.75),
arrowprops = dict(
arrowstyle='->', connectionstyle='arc3,rad=0'))
return annotation
def snap(self, x, y):
"""Return the value in self.tree closest to x, y."""
dist, idx = self.tree.query(self.scaled((x, y)), k=1, p=1)
try:
return self._points[idx]
except IndexError:
# IndexError: index out of bounds
return self._points[0]
class MainWindow(QMainWindow):
def __init__(self):
super().__init__()
self.width = 1000
self.height = 800
self.setGeometry(0, 0, self.width, self.height)
canvas = self.get_canvas()
w = QWidget()
w.layout = QHBoxLayout()
w.layout.addWidget(canvas)
w.setLayout(w.layout)
self.setCentralWidget(w)
self.show()
def get_canvas(self):
fig, ax = plt.subplots()
x = np.linspace(0.1, 2*pi, 10)
y = cos(x)
markerline, stemlines, baseline = ax.stem(x, y, '-.')
plt.setp(markerline, 'markerfacecolor', 'b')
plt.setp(baseline, 'color','r', 'linewidth', 2)
cursor = FollowDotCursor(ax, x, y, tolerance=20)
canvas = FigureCanvas(fig)
return canvas
app = QApplication(sys.argv)
win = MainWindow()
sys.exit(app.exec_())
What would I have to do to make the labels also show when hovering over in the pyqt application?
The first problem may be that you don't keep a reference to the FollowDotCursor.
So to make sure the FollowDotCursor stays alive, you can make it a class variable
self.cursor = FollowDotCursor(ax, x, y, tolerance=20)
instead of cursor = ....
Next make sure you instatiate the Cursor class after giving the figure a canvas.
canvas = FigureCanvas(fig)
self.cursor = FollowDotCursor(ax, x, y, tolerance=20)
Finally, keep a reference to the callback inside the FollowDotCursor and don't use plt.connect but the canvas itself:
self.cid = self.fig.canvas.mpl_connect('motion_notify_event', self)
I tried assigning a plotting function with the wx.Timer so that the graph is plotted every 1000 milliseconds. Yet, the graph is not appearing at at all.
class GPanel0(wx.Panel):
def __init__(self, parent):
wx.Panel.__init__(self, parent)
self.figure = Figure()
self.axes = self.figure.add_subplot(111)
self.canvas = FigureCanvas(self, -1, self.figure)
self.sizer = wx.BoxSizer(wx.VERTICAL)
self.sizer.Add(self.canvas, 1, wx.LEFT | wx.TOP | wx.GROW)
self.SetSizer(self.sizer)
self.timer = wx.Timer(self)
self.Bind(wx.EVT_TIMER, self.draw, self.timer)
self.timer.Start(1000)
def draw(self, event):
y, x=np.loadtxt('bv.txt',delimiter=',', unpack=True)
self.axes.plot(x, y)
def ShowYourself(self):
self.Raise()
self.SetPosition((0,2))
self.Fit()
self.Show()
yet the graph does not plot a single set of variables at all. It seems as if the timer function does not work with plotting.
I am pretty new to this so please do mind errors and mistakes in the question.