Carpet plots: showlegend not working

[pfbuxton]

In this example the showlegend does not cause a legend to show.

import dash
import dash_core_components as dcc
import dash_html_components as html
import plotly.graph_objs as go

app = dash.Dash(__name__)

traces = []
traces.append(go.Carpet(
    a = [4, 4, 4, 4.5, 4.5, 4.5, 5, 5, 5, 6, 6, 6],
    b = [1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3],
    y = [2, 3.5, 4, 3, 4.5, 5, 5.5, 6.5, 7.5, 8, 8.5, 10],
    name='test',
    showlegend=True
))

layout = []

app.layout = html.Div(children=[
    html.H1(children='showlegend within Carpet not showing'),
    
    html.Div([
        dcc.Graph(
            id='Recon_plasma_image',
            config=dict( displayModeBar=False ),
            figure=dict( data=traces, layout=layout )
        )
    ], style={ 'width':'500px', 'height':'600px' }),
])

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

Also in this example legendgroup does not seem to work either.

import dash
import dash_core_components as dcc
import dash_html_components as html
import plotly.graph_objs as go

app = dash.Dash(__name__)

traces = []
traces.append(go.Carpet(
    a = [4, 4, 4, 4.5, 4.5, 4.5, 5, 5, 5, 6, 6, 6],
    b = [1, 2, 3, 1, 2, 3, 1, 2, 3, 1, 2, 3],
    y = [2, 3.5, 4, 3, 4.5, 5, 5.5, 6.5, 7.5, 8, 8.5, 10],
    name='test',
    showlegend=False,
    carpet='c1',
    legendgroup='group1',
))
traces.append(go.Scatter(
    x=[0.1, 0.2],
    y=[1, 2],
    showlegend=False,
    legendgroup='group1',
    mode='lines',
    line=dict( color='black', dash='solid' ),
))
traces.append(go.Scatter(
    x=[1, 2],
    y=[1, 2],
    showlegend=True,
    name='group1 name',
    legendgroup='group1',
    mode='lines',
    line=dict( color='black', dash='solid' ),
))

layout = []

app.layout = html.Div(children=[
    html.H1(children='legendgroup not working with the Carpet plot'),
    
    html.Div([
        dcc.Graph(
            id='Recon_plasma_image',
            config=dict( displayModeBar=False ),
            figure=dict( data=traces, layout=layout )
        )
    ], style={ 'width':'500px', 'height':'600px' }),
])

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

Have I understood this correctly and should showlegend and legendgroup do what I thought?

Thanks,
Peter

[jonmmease]

Hi @pfbuxton,

Carpet traces don't support legend entries unfortunately. Prior to plotly.py version 3.8 the showlegend and legendgroup properties were included in every trace, including those that don't support legends. This was cleaned up in version 3.8 and there is not a validation error raised what these properties are provided to traces that don't support legends.

Feel free to open a feature request in the Plotly.js project (https://github.com/plotly/plotly.js/issues) for carpet legend support.

[pfbuxton]

Feature requested on Plotly.js:
plotly/plotly.js#3828