CODEWITHSUNDEEP
pythonpyqt5mouseeventpyqtgraphviewbox
kalzso
kalzso

Reputation: 536

PyQtGraph disable mouse wheel, but leave other functions of the mouse untouched

I have a pyqtgraph.ViewBox widget with an image in it. The mouse is enabled, so I can select a rectangle on the image and it will be zoomed. But there is an unwanted feature, the zooming occurs on the mouse wheel scrolling aswell.

How can I disable the mouse wheel only, and leave the rest as is?

from PyQt5.QtWidgets import QApplication, QMainWindow
import pyqtgraph as pg
import cv2


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        pg.setConfigOption('imageAxisOrder', 'row-major')
        pg.setConfigOption('leftButtonPan', False)  # if False, then dragging the left mouse button draws a rectangle
    
        self.grid = pg.GraphicsLayoutWidget()
        self.top_left = self.grid.addViewBox(row=1, col=1)

        image = cv2.imread('/path/to/your/image.jpg', cv2.IMREAD_UNCHANGED)
        self.image_item = pg.ImageItem()
        self.image_item.setImage(image)
        self.top_left.addItem(self.image_item)

        self.setCentralWidget(self.grid)


def main():
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()


if __name__ == '__main__':
    main()

Upvotes: 0

Views: 2731

Answers (2)

Edward Kigwana
Edward Kigwana

Reputation: 334

It is way simpler than the accepted answer. Use setMouseEnabled on the ViewBox:

from PyQt5.QtWidgets import QApplication, QMainWindow
import pyqtgraph as pg
import cv2


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        pg.setConfigOption('imageAxisOrder', 'row-major')
        pg.setConfigOption('leftButtonPan', False)  # if False, then dragging the left mouse button draws a rectangle

        self.grid = pg.GraphicsLayoutWidget()
        self.top_left = self.grid.addViewBox(row=1, col=1)
        self.top_left.setMouseEnabled(x=False, y=False)  # <--- Add this line

        image = cv2.imread('/path/to/your/image.jpg', cv2.IMREAD_UNCHANGED)
        self.image_item = pg.ImageItem()
        self.image_item.setImage(image)
        self.top_left.addItem(self.image_item)

        self.setCentralWidget(self.grid)


def main():
    app = QApplication([])
    window = MainWindow()
    window.show()
    app.exec_()


if __name__ == '__main__':
    main()

Upvotes: 2

alec
alec

Reputation: 6122

You can install an event filter on the ViewBox and catch the mouse wheel event, in this case QEvent.GraphicsSceneWheel.

from PyQt5.QtWidgets import QApplication, QMainWindow
from PyQt5.QtCore import QEvent
import pyqtgraph as pg
import cv2


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        pg.setConfigOption('imageAxisOrder', 'row-major')
        pg.setConfigOption('leftButtonPan', False)  # if False, then dragging the left mouse button draws a rectangle
    
        self.grid = pg.GraphicsLayoutWidget()
        self.top_left = self.grid.addViewBox(row=1, col=1)
        self.top_left.installEventFilter(self)

        image = cv2.imread('/path/to/your/image.jpg', cv2.IMREAD_UNCHANGED)
        self.image_item = pg.ImageItem()
        self.image_item.setImage(image)
        self.top_left.addItem(self.image_item)

        self.setCentralWidget(self.grid)

    def eventFilter(self, watched, event):
        if event.type() == QEvent.GraphicsSceneWheel:
            return True
        return super().eventFilter(watched, event)

Upvotes: 1

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