Get width and height of plotly figure

Question

e.g. if I write

import plotly.express as px

df = px.data.tips()
fig = px.scatter(df, x="total_bill", y="tip", facet_col="sex")

then how can I get the width and height of fig?

If I do

fig.layout.width

then I get None.

Answer 1

That is the correct way to get the width.

fig.layout.width is None because the width has not been set yet.

If you set it explicitly you can retrieve it

fig = px.scatter(df, x="total_bill", y="tip", facet_col="sex", width=200)
>>> fig.layout.width
200

If not set explicitly the width is initialised when executing the show method based on defaults defined by plotly.js.

show(*args, **kwargs) Show a figure using either the default renderer(s) or the renderer(s) specified by the renderer argument

Parameters
...
width (int or float) – An integer or float that determines the number of pixels wide the plot is. The default is set in plotly.js.
...

If we look at the plotly.js documentation we see the default width is 700 and the default height is 450.

If you set fig.layout.autosize = False you can see that these defaults are correct. Otherwise the width and height are re-initialised on each relayout.

autosize: Determines whether or not a layout width or height that has been left undefined by the user is initialized on each relayout. Note that, regardless of this attribute, an undefined layout width or height is always initialized on the first call to plot.

https://plotly.com/javascript/reference/layout/#layout-autosize