Supported CSS Colors in Python

A list of supported named CSS Colors

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Supported CSS Colors¶

Many properties in Plotly.py for configuring colors support named CSS colors. For example, marker colors:

In [1]:

import plotly.graph_objects as go

fig = go.Figure([
    go.Bar(
        x=['Jan', 'Feb', 'Mar', 'Apr'],
        y=[20, 14, 25, 16],
        name='Primary Product',
        # Named CSS color
        marker_color='royalblue'
    )
])

fig.show()

These colors are supported in Plotly.py when a property accepts a named CSS color.

Other Color Formats¶

Changed in 7.0

As well as named colors, color properties accept color strings in the formats defined by the CSS Color 4 specification, including rgb(), rgba(), hsl(), hsla(), hwb(), lab(), lch(), oklab(), oklch(), color(), and hexadecimal notation with a leading #.

Version 7 parses these strings according to that specification. Four formats that earlier versions accepted no longer give the same result. A string that cannot be parsed at all falls back to the property's default:

No longer works	Example	Use instead
The `hsv()` color function	`"hsv(200, 80%, 80%)"`	`"hsl(200, 67%, 47%)"`, `"hwb()"`, hexadecimal, or `"rgb()"`
Comma separated saturation and lightness values without percent units	`"hsl(0, 100, 40)"`	`"hsl(0, 100%, 40%)"`, or the space separated `"hsl(0 100 40)"`
Channel values given as fractions of 1	`"rgb(0.5, 0.5, 0.5)"` (now renders as near black)	`"rgb(128, 128, 128)"`
Hexadecimal values without a leading `#`	`"fff"`	`"#fff"`

These rules apply to color strings only. Numeric arrays used with a colorscale are unaffected.

Converting a Hexadecimal Color to RGB¶

Changed in 7.1

plotly.colors.hex_to_rgb converts a hexadecimal color string to a tuple of red, green, and blue values. It takes 3 or 6 hexadecimal digits, with or without a leading #:

In [3]:

import plotly.colors as colors

print(colors.hex_to_rgb("#EF553B"))
print(colors.hex_to_rgb("#FFF"))

(239, 85, 59)
(255, 255, 255)

A 4-digit or 8-digit string carries an alpha channel, which a tuple of red, green, and blue values cannot hold. hex_to_rgb drops the alpha channel, warns, and returns the 3 remaining values. Earlier versions returned 4 values instead of 3.

Any other length raises a ValueError, which version 7.1 added. Earlier versions returned a tuple of the wrong length. hex_to_rgb("#FFFF0") returned 5 values, one for each digit.

What About Dash?¶

Dash is an open-source framework for building analytical applications, with no Javascript required, and it is tightly integrated with the Plotly graphing library.

Learn about how to install Dash at https://dash.plot.ly/installation.

Everywhere in this page that you see fig.show(), you can display the same figure in a Dash application by passing it to the figure argument of the Graph component from the built-in dash_core_components package like this:

import plotly.graph_objects as go # or plotly.express as px
fig = go.Figure() # or any Plotly Express function e.g. px.bar(...)
# fig.add_trace( ... )
# fig.update_layout( ... )

from dash import Dash, dcc, html

app = Dash()
app.layout = html.Div([
    dcc.Graph(figure=fig)
])

app.run(debug=True, use_reloader=False)  # Turn off reloader if inside Jupyter