Slider widget for PyQtGraph

Question

Is it possible to get a slider widget for PyQtGraph? So that e.g. one or more widgets could control parameters from a plot. Like in this example below (made with enaml/chaco):

I could find nothing like this in the examples or in the list of PyQtGraph widgets. Perhaps one can use a widget from Qt and link it to the PyQtGraph plot object?

Answer 1

It is possible to use any widget of Qt next to pyqtgraph, the graphic objects of pyqtgraph inherit from QWidget, that is to say, they are generics widgets. Here is an example.

import sys

from PyQt5.QtCore import Qt
from PyQt5.QtWidgets import QApplication, QHBoxLayout, QLabel, QSizePolicy, QSlider, QSpacerItem, \
    QVBoxLayout, QWidget

import pyqtgraph as pg
import numpy as np


class Slider(QWidget):
    def __init__(self, minimum, maximum, parent=None):
        super(Slider, self).__init__(parent=parent)
        self.verticalLayout = QVBoxLayout(self)
        self.label = QLabel(self)
        self.verticalLayout.addWidget(self.label)
        self.horizontalLayout = QHBoxLayout()
        spacerItem = QSpacerItem(0, 20, QSizePolicy.Expanding, QSizePolicy.Minimum)
        self.horizontalLayout.addItem(spacerItem)
        self.slider = QSlider(self)
        self.slider.setOrientation(Qt.Vertical)
        self.horizontalLayout.addWidget(self.slider)
        spacerItem1 = QSpacerItem(0, 20, QSizePolicy.Expanding, QSizePolicy.Minimum)
        self.horizontalLayout.addItem(spacerItem1)
        self.verticalLayout.addLayout(self.horizontalLayout)
        self.resize(self.sizeHint())

        self.minimum = minimum
        self.maximum = maximum
        self.slider.valueChanged.connect(self.setLabelValue)
        self.x = None
        self.setLabelValue(self.slider.value())

    def setLabelValue(self, value):
        self.x = self.minimum + (float(value) / (self.slider.maximum() - self.slider.minimum())) * (
        self.maximum - self.minimum)
        self.label.setText("{0:.4g}".format(self.x))


class Widget(QWidget):
    def __init__(self, parent=None):
        super(Widget, self).__init__(parent=parent)
        self.horizontalLayout = QHBoxLayout(self)
        self.w1 = Slider(-10, 10)
        self.horizontalLayout.addWidget(self.w1)

        self.w2 = Slider(-1, 1)
        self.horizontalLayout.addWidget(self.w2)

        self.w3 = Slider(-10, 10)
        self.horizontalLayout.addWidget(self.w3)

        self.w4 = Slider(-10, 10)
        self.horizontalLayout.addWidget(self.w4)

        self.win = pg.GraphicsWindow(title="Basic plotting examples")
        self.horizontalLayout.addWidget(self.win)
        self.p6 = self.win.addPlot(title="My Plot")
        self.curve = self.p6.plot(pen='r')
        self.update_plot()

        self.w1.slider.valueChanged.connect(self.update_plot)
        self.w2.slider.valueChanged.connect(self.update_plot)
        self.w3.slider.valueChanged.connect(self.update_plot)
        self.w4.slider.valueChanged.connect(self.update_plot)

    def update_plot(self):
        a = self.w1.x
        b = self.w2.x
        c = self.w3.x
        d = self.w4.x
        x = np.linspace(0, 10, 100)
        data = a + np.cos(x + c * np.pi / 180) * np.exp(-b * x) * d
        self.curve.setData(data)


if __name__ == '__main__':
    app = QApplication(sys.argv)
    w = Widget()
    w.show()
    sys.exit(app.exec_())