Plot Subtitle

I was wondering if there is a way to add a plot subtitle in plotly. Sometimes it would be very important to be able to add extra information regarding the plot in a line below the main title. It would also be great if it would be possible to add this subtitle within a “subtitle” tag on the layout description of the plot. Something such as:

var layout = { -----title: ‘Plot Title’, -----subtitle: ‘Plot Subtitle’, -----xaxis: { ----------title: ‘x Axis’, ----------titlefont: { ----------family: ‘Courier New, monospace’, ----------size: 18, ----------color: ‘#7f7f7f’ ----------} -----}, -----yaxis: { ----------title: ‘y Axis’, ----------titlefont: { ---------------family: ‘Courier New, monospace’, ---------------size: 18, ---------------color: ‘#7f7f7f’ ---------------} -----} };

I have searched on internet and I couldn’t find any way to implement this subtitle on plotly. Even though I couldn’t find anything I could edit the source code loaded on my browser to insert a subtitle within the <text class="gtitle" ...> ... </text> by adding a <tspan style="..."> </span>. Even though this worked for the plot display then the “download plot as a png” option from the “modebar” of the plot was not capable to save this change in a picture.

I know this might be an enhancement, hopefully it is not hardcoding and it is easy to implement.

Thank you very much!

[floriandierickx]

@leonardotrp, I had the same issue. The small tag does not seem to work. I created a small subtitle by rendering with a break and using the allowed <sub> tag:

'layout': {
            'title': 'Historical Emissions and Future Emission Budget for {} <br><sub>Source: @FlorianDRX</sub>'.format(selected_country) ,
            'xaxis': {
                'title': 'Year'
            },
            'yaxis': {
                'title': 'National Emissions (Megatons CO2)'
            },
        },

Which renders the title as:

[cyberosa]

In plot there is already this feature, you have “main” and “sub”
https://www.statmethods.net/advgraphs/axes.html

I sum my vote also to have this feature in plotly!