CODEWITHSUNDEEP
pythonpyqtpyqt5autoscalingpyqtgraph
Rémi Baudoux
Rémi Baudoux

Reputation: 559

link auto-scale on multiple plots in pyqtgraph

Is it possible link the auto-scale of several plots? I want to scale all the plots with which ever is the biggest range on all curves of all plots.

Is there way to make it with a pyqtgraph function, or should I find the max, min and set the scale with a custom function?

I am using pyqtgraph on PyQt5

Upvotes: 1

Views: 1525

Answers (1)

nathancy
nathancy

Reputation: 46630

Pyqtgraph should automatically scale the y-axis on multiple plots with which ever has the largest range. Here's an example widget with auto-scaling plots in PyQt4 but the concept should be the same for PyQt5.

Example gif

import pyqtgraph as pg
from pyqtgraph.Qt import QtCore, QtGui
import numpy as np
import sys
import random

class AutoScaleMultiplePlotWidget(QtGui.QWidget):
    def __init__(self, parent=None):
        super(AutoScaleMultiplePlotWidget, self).__init__(parent)

        self.NUMBER_OF_PLOTS = 4
        self.LEFT_X = 0 
        self.RIGHT_X = 5
        self.SPACING = 1
        self.x_axis = np.arange(self.LEFT_X, self.RIGHT_X + 1, self.SPACING)
        self.buffer_size = int((abs(self.LEFT_X) + abs(self.RIGHT_X) + 1)/self.SPACING)

        self.auto_scale_plot_widget = pg.PlotWidget()
        self.auto_scale_plot_widget.setLabel('left', 'left axis')

        # Create plots
        self.left_plot1 = self.auto_scale_plot_widget.plot()
        self.left_plot2 = self.auto_scale_plot_widget.plot()
        self.left_plot3 = self.auto_scale_plot_widget.plot()
        self.left_plot4 = self.auto_scale_plot_widget.plot()

        self.left_plot1.setPen((173,255,129), width=1)
        self.left_plot2.setPen((172,187,255), width=1)
        self.left_plot3.setPen((255,190,116), width=1)
        self.left_plot4.setPen((204,120,255), width=1)

        self.initialize_plot_buffers()
        self.initialize_data_buffers()

        self.layout = QtGui.QGridLayout()
        self.layout.addWidget(self.auto_scale_plot_widget)

        self.start()

    def initialize_data_buffers(self):
        """Create blank data buffers for each curve"""

        self.data_buffers = []
        for trace in range(self.NUMBER_OF_PLOTS):
            self.data_buffers.append([0])

    def initialize_plot_buffers(self):
        """Add plots into buffer for each curve"""

        self.plots = []
        self.plots.append(self.left_plot1)
        self.plots.append(self.left_plot2)
        self.plots.append(self.left_plot3)
        self.plots.append(self.left_plot4)

    def update_plot(self):
        """Generates new random value and plots curve onto plot"""

        for trace in range(self.NUMBER_OF_PLOTS):
            if len(self.data_buffers[trace]) >= self.buffer_size:
                self.data_buffers[trace].pop(0)
            data_point = self.data_buffers[trace][-1] + random.randint(10,50)
            self.data_buffers[trace].append(float(data_point))

            self.plots[trace].setData(self.x_axis[len(self.x_axis) - len(self.data_buffers[trace]):], self.data_buffers[trace])

    def get_auto_scale_plot_layout(self):
        return self.layout

    def start(self):
        self.multiple_axis_plot_timer = QtCore.QTimer()
        self.multiple_axis_plot_timer.timeout.connect(self.update_plot)
        self.multiple_axis_plot_timer.start(500)

if __name__ == '__main__':

    # Create main application window
    app = QtGui.QApplication([])
    app.setStyle(QtGui.QStyleFactory.create("Cleanlooks"))
    mw = QtGui.QMainWindow()
    mw.setWindowTitle('Auto Scale Multiple Plot Example')

    # Create plot
    auto_scale_plot = AutoScaleMultiplePlotWidget()

    # Create and set widget layout
    # Main widget container
    cw = QtGui.QWidget()
    ml = QtGui.QGridLayout()
    cw.setLayout(ml)
    mw.setCentralWidget(cw)

    # Add plot to main layout
    ml.addLayout(auto_scale_plot.get_auto_scale_plot_layout(),0,0)

    mw.show()

    if(sys.flags.interactive != 1) or not hasattr(QtCore, 'PYQT_VERSION'):
        QtGui.QApplication.instance().exec_()

Upvotes: 1

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