Is it possible to recreate a pyqtgraph without data - pyqt5

Question

I have a pyqt5 based application where I open a file and plot 2 different plots based on the data from the file. Now I want to open another similar file, but I want to save the status/view of the 2 plots, so that I could come quickly back to the previous plots/views, without having to plot it again by reading the data. Is it possible at all to save the state/view of the plots to recreate it very quickly?

Answer 1

You can guide from this answer .
Basically, you can use the PlotWidget class from pyqtgraph.
Generate a PlotWidget.
import pyqtgraph as pg
plot_widget = pg.PlotWidget()
Use the plot() method and store the PlotDataItem in a variable. The PlotDataItem will contain the information of that specific plot: x-data, y-data, the color of the line, the line width, ...
plot_item = plot_widget.plot(xData, yData)
With this you can add/remove the item from the plot every time you want with the addItem() and removeItem() methods
plot_widget.removeItem(plot_item)
plot_widget.addItem(plot_item)
EDIT:
To get the view state of the plot, you can use the viewRect() method of the PlotWidget class. It will return a QRectF object which contains the information of the view state like this:
PyQt5.QtCore.QRectF(x_0, y_0, w, h)
Where:
x_0 and y_0 are the coordinates where the view starts.
w and h are the width and height of the view area.
Also, you can restore the view using the setRange() method of the PlotWidget class.
Example:
Here is an example of the implementation of this:
import sys
import numpy as np
import pyqtgraph as pg
from pyqtgraph.Qt import QtGui
class MyApp(QtGui.QWidget):
def __init__(self):
QtGui.QWidget.__init__(self)
self.central_layout = QtGui.QVBoxLayout()
self.buttons_layout = QtGui.QVBoxLayout()
self.boxes_layout = QtGui.QHBoxLayout()
self.save = QtGui.QPushButton('Save View')
self.set = QtGui.QPushButton('Set View')
self.boxes = [QtGui.QCheckBox(f"Box {i+1}") for i in range(3)]
self.plot_widget = pg.PlotWidget()
self.plot_data = [None for _ in range(3)]
self.state = [False for _ in range(3)]
self.setLayout(self.central_layout)
self.central_layout.addWidget(self.plot_widget)
self.central_layout.addLayout(self.buttons_layout)
self.buttons_layout.addLayout(self.boxes_layout)
self.buttons_layout.addWidget(self.save)
self.buttons_layout.addWidget(self.set)
for i in range(3):
self.boxes_layout.addWidget(self.boxes[i])
self.boxes[i].stateChanged.connect(self.box_changed)
self.create_data()
self.save.clicked.connect(self.save_view)
self.set.clicked.connect(self.set_view)
self.view_state = None
self.save_view()
def create_data(self):
x = np.linspace(0, 3.14, 100)
y = [np.sin(x), np.cos(x), np.sin(x)**2]
for i in range(3):
self.plot_data[i] = pg.PlotDataItem(x, y[i])
def box_changed(self):
for i in range(3):
if self.boxes[i].isChecked() != self.state[i]:
self.state[i] = self.boxes[i].isChecked()
if self.state[i]:
if self.plot_data[i] is not None:
self.plot_widget.addItem(self.plot_data[i])
else:
self.plot_data[i] = self.plot_widget.plot(*self.box_data[i])
else:
self.plot_widget.removeItem(self.plot_data[i])
break
def save_view(self):
self.view_state = self.plot_widget.viewRect()
def set_view(self):
self.plot_widget.setRange(self.view_state)
if __name__ == '__main__':
app = QtGui.QApplication(sys.argv)
window = MyApp()
window.show()
sys.exit(app.exec_())