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      "source": [
        "%gui qt"
      ]
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      "cell_type": "markdown",
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      "source": [
        "\n# Display an Isocurve\n\nSimple use of SceneCanvas to display an Isocurve visual.\n"
      ]
    },
    {
      "cell_type": "code",
      "execution_count": null,
      "metadata": {
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      "source": [
        "import sys\nfrom vispy import app, scene, visuals\nfrom vispy.util.filter import gaussian_filter\nimport numpy as np\n\ncanvas = scene.SceneCanvas(keys='interactive', title='Isocurve(s) overlayed '\n                           'over Random Image Example')\ncanvas.size = 800, 600\ncanvas.show()\n\n# Set up a viewbox to display the image with interactive pan/zoom\nview = canvas.central_widget.add_view()\n\n# Create the image\nimg_data = np.empty((200, 100, 3), dtype=np.ubyte)\nnoise = np.random.normal(size=(200, 100), loc=50, scale=150)\nnoise = gaussian_filter(noise, (4, 4, 0))\nimg_data[:] = noise[..., np.newaxis]\nimage = scene.visuals.Image(img_data, parent=view.scene)\n# move image behind curves\nimage.transform = visuals.transforms.STTransform(translate=(0, 0, 0.5))\n\n# level and color setup\nlevels = [40, 50, 60]\ncolor_lev = [(1, 0, 0, 1),\n             (1, 0.5, 0, 1),\n             (1, 1, 0, 1)]\n\n# Create isocurve, make a child of the image to ensure the two are always\n# aligned.\ncurve = scene.visuals.Isocurve(noise, levels=levels, color_lev=color_lev,\n                               parent=view.scene)\n\n# Set 2D camera\nview.camera = scene.PanZoomCamera(aspect=1)\n# the camera will scale to the contents in the scene\nview.camera.set_range()\n\nif __name__ == '__main__' and sys.flags.interactive == 0:\n    app.run()"
      ]
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