Themes

Default Theme

Deneb's default theme (:default) consists of a toplevel config property that sets the default size and enables tooltips by default:

print_theme()

{
  "config": {
    "view": {
      "continuousWidth": 300,
      "continuousHeight": 300,
      "step": 25
    },
    "mark": {
      "tooltip": true
    }
  }
}

The rendered chart reflects this configuration:

chart = Data(
    url="https://vega.github.io/vega-datasets/data/stocks.csv"
) * Mark(
    :line, point=true
) * Encoding(
    "year(date):T",
    "mean(price):Q",
    color=:symbol,
)
chart

The choice to increase VegaLite's default size and to enable tooltips by default is an opinionated one. The next section explains how to disable Deneb's default theme and use VegaLite's instead.

Changing the theme

The method set_theme! changes the theme during the length of your Julia session. For instance, the theme :empty disables the toplevel config so Vega-Lite's defaults are used:

set_theme!(:empty)
print_theme()

{}

The chart renders as:

chart

Note the smaller figure size and that tooltips aren't enabled.

A default theme with the default figure size but no tooltips, :default_no_tooltip:, is also available:

set_theme!(:default_no_tooltip)
print_theme()

{
  "config": {
    "view": {
      "continuousWidth": 300,
      "continuousHeight": 300,
      "step": 25
    }
  }
}

chart

Vega themes

Other available themes are Vega Themes. For example, the :quartz theme:

set_theme!(:quartz)
chart

And the :fivethirtyeight theme:

set_theme!(:fivethirtyeight)
chart

User defined themes

A custom theme can be specified by defining a top level config using a NamedTuple. For example, the following user defined theme is equivalent to the Vega :dark theme:

config = (
  background="#333",
  title=(color="#fff", subtitleColor="#fff"),
  style=(;Symbol("guide-label")=>(;fill="#fff"), Symbol("guide-title")=>(;fill="#fff")),
  axis=(domainColor="#fff", gridColor="#888", tickColor="#fff")
)
set_theme!(config)
chart