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# Display an Isocurve

Simple use of SceneCanvas to display an Isocurve visual.

    import sys
    from vispy import app, scene, visuals
    from vispy.util.filter import gaussian_filter
    import numpy as np

    canvas = scene.SceneCanvas(keys='interactive', title='Isocurve(s) overlayed '
                               'over Random Image Example')
    canvas.size = 800, 600
    canvas.show()

    # Set up a viewbox to display the image with interactive pan/zoom
    view = canvas.central_widget.add_view()

    # Create the image
    img_data = np.empty((200, 100, 3), dtype=np.ubyte)
    noise = np.random.normal(size=(200, 100), loc=50, scale=150)
    noise = gaussian_filter(noise, (4, 4, 0))
    img_data[:] = noise[..., np.newaxis]
    image = scene.visuals.Image(img_data, parent=view.scene)
    # move image behind curves
    image.transform = visuals.transforms.STTransform(translate=(0, 0, 0.5))

    # level and color setup
    levels = [40, 50, 60]
    color_lev = [(1, 0, 0, 1),
                 (1, 0.5, 0, 1),
                 (1, 1, 0, 1)]

    # Create isocurve, make a child of the image to ensure the two are always
    # aligned.
    curve = scene.visuals.Isocurve(noise, levels=levels, color_lev=color_lev,
                                   parent=view.scene)

    # Set 2D camera
    view.camera = scene.PanZoomCamera(aspect=1)
    # the camera will scale to the contents in the scene
    view.camera.set_range()

    if __name__ == '__main__' and sys.flags.interactive == 0:
        app.run()

Total running time of the script: (0 minutes 0.747 seconds)

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