Issue with Image Clipping in Multiple Viewboxes about vispy HOT 3 CLOSED

from vispy import app, scene
import numpy as np
from vispy.scene.cameras import TurntableCamera
from vispy.io import load_data_file, read_png


class Blending_image(scene.visuals.Image):

    def __init__(self):
        scene.visuals.Image.__init__(self, parent=None)
        self.unfreeze()
        self.overlaid_images = [self]

        # NOTE: Here, I set img2's parent as img1.
        # So when apply some transform on img1, 
        # img2 can be add the same effect.
        img2 = scene.visuals.Image(parent=self) 
        self.overlaid_images.append(img2)
        # Set GL state. Must check depth test, otherwise weird in 3D.
        self.set_gl_state(depth_test=True,
                          depth_func='lequal',
                          blend_func=('src_alpha', 'one_minus_src_alpha'))
        self.freeze()

    def set_data2(self, img1, img2):
        self.set_data(img1)
        self.overlaid_images[1].set_data(img2)

canvas = scene.SceneCanvas(keys='interactive', bgcolor='white')

vb1 = scene.widgets.ViewBox(parent=canvas.scene)
vb2 = scene.widgets.ViewBox(parent=canvas.scene)

grid = canvas.central_widget.add_grid()
grid.padding = 20
grid.add_widget(vb1, 0, 0)
grid.add_widget(vb2, 0, 1)

vb1.camera = TurntableCamera(fov=45, azimuth=0, elevation=-90)
vb2.camera = TurntableCamera(fov=45, azimuth=0, elevation=-90)

# Create the image
root = 'mona_lisa/mona_lisa_sm.png'
img_data1 = read_png(load_data_file(root))[:500, :500, :]
img_data2 = read_png(load_data_file(root))[-500:, :500, :]

img_ov1data = np.ones((500, 500, 4)).astype(np.float32)
img_ov1data[:, :, 3] = 0.5
img_ov2data = np.random.rand(500, 500, 4).astype(np.float32)
img_ov2data[:, :, 3] = 0.5

image1 = Blending_image()
image1.set_data2(img_data1, img_ov1data)
image2 = Blending_image()
image2.set_data2(img_data2, img_ov2data)

vb1.add(image1)
vb2.add(image2)

vb1.camera.set_range()
vb2.camera.set_range()
vb1.camera.link(vb2.camera)

canvas.show()
app.run()

vb1.add(image1)
vb1.add(image1.overlaid_images[-1])
vb2.add(image2)
vb2.add(image2.overlaid_images[-1])

class Blending_image(scene.visuals.Image):
    ......
    ......
    def _set_clipper(self, node, clipper):
        """
        To clipper its children

        Assign a clipper that is inherited from a parent node.

        If *clipper* is None, then remove any clippers for *node*.
        """
        super()._set_clipper(node, clipper)

        for im in self.children:
            if isinstance(im, scene.visuals.Image):
                if node in im._clippers:
                    im.detach(self._clippers.pop(node))
                if clipper is not None:
                    im.attach(clipper)
                    im._clippers[node] = clipper