v_slice.py

# -*- coding: utf-8 -*-
import dash
import dash_core_components as dcc
import dash_html_components as html
import numpy as np
import plotly.graph_objects as go
from scipy import ndimage

external_stylesheets = ['https://codepen.io/chriddyp/pen/bWLwgP.css']

app = dash.Dash(__name__, external_stylesheets=external_stylesheets)

# Generate nicely looking random 3D-field
np.random.seed(0)
l = 30
X, Y, Z = np.mgrid[:l, :l, :l]
vol = np.zeros((l, l, l))
pts = (l * np.random.rand(3, 15)).astype(np.int)
vol[tuple(indices for indices in pts)] = 1
vol = ndimage.gaussian_filter(vol, 4)
vol /= vol.max()

fig = go.Figure(data=go.Volume(
    x=X.flatten(), y=Y.flatten(), z=Z.flatten(), 
    value=vol.flatten(),
    isomin=0.2,
    isomax=0.7,
    opacity=0.1,
    surface_count=25,
    slices_z=dict(fill=1, show=True, locations=[10.0]),
    surface=dict(fill=1),
    caps= dict(x_show=False, y_show=False, z_show=False), # no caps
    ))

fig.layout = dict(
    uirevision=True,
    height=600
)

camera = dict(eye=dict(x=2.5, y=0., z=0.8))

fig.update_layout(scene_camera=camera)

app.layout = html.Div([
    html.Div([
        html.Div([
            html.P(children='volume fill'),
            dcc.Slider(id='fill', min=0, max=1, step=0.1, value=1),
            html.P(children='z slice position'),
            dcc.Slider(id='z_slider', min=0, max=29.0, step=0.1, value=10.0),
            dcc.Graph(id='volume', figure=fig)
        ], className="six columns"),
        html.Div([
            dcc.Graph(id='contour', figure={})
        ], className="six columns"),
    ], className="row")
])

@app.callback(
    [dash.dependencies.Output('volume', 'figure'),
    dash.dependencies.Output('contour', 'figure')],
    [dash.dependencies.Input('z_slider', 'value'),
    dash.dependencies.Input('fill', 'value')])
def move_slice_v(slider_position, fill):
    fig['data'][0]['slices_z']['locations'] = [slider_position]
    fig['data'][0]['surface']['fill'] = fill
    index = int(slider_position/29.0 * 29.0)
    contour_data = vol[:,:,index]
    contour = go.Figure(
        data=go.Contour(z = contour_data, connectgaps=False),
        layout=go.Layout(
            height=500, width=500, 
            title='z-plane: z={0}'.format(slider_position),
            yaxis=go.YAxis(autorange="reversed")
        )
    )
    return fig, contour

if __name__ == '__main__':
    app.run_server(debug=True)