Themes

Many parameters controlling the appearance of plots can be overridden by passing a Theme object to the plot function. Or setting the Theme as the current theme using push_theme (see also pop_theme and with_theme below).

The constructor for Theme takes zero or more named arguments each of which overrides the default value of the field.

The Theme stack

Gadfly maintains a stack of themes and applies theme values from the topmost theme in the stack. This can be useful when you want to set a theme for multiple plots and then switch back to a previous theme.

push_theme(t::Theme) and pop_theme() will push and pop from this stack respectively. You can use with_theme(f, t::Theme) to set a theme as the current theme and call f().

style

You can use style to override the fields on top of the current theme at the top of the stack. style(...) returns a Theme. So it can be used with push_theme and with_theme.

Parameters

These parameters can either be used with Theme or style

• default_color: When the color aesthetic is not bound, geometry uses this color for drawing. (Color)

• point_size: Size of points in the point, boxplot, and beeswarm geometries. (Measure)

• point_size_min: Minimum size of points in the point geometry. (Measure)

• point_size_max: Maximum size of points in the point geometry. (Measure)

• point_shapes: Shapes of points in the point geometry. (Function in circle, square, diamond, cross, xcross, utriangle, dtriangle, star1, star2, hexagon, octagon, hline, vline)

• line_width: Width of lines in the line geometry. (Measure)

• line_style: Style of lines in the line geometry. (Symbol in :solid, :dash, :dot, :dashdot, :dashdotdot, or Vector of Measures)

• panel_fill: Background color used in the main plot panel. ( Color or Nothing)

• panel_opacity: Opacity of the plot background panel. (Float in [0.0, 1.0])

• panel_stroke: Border color of the main plot panel. (Color or Nothing)

• background_color: Background color for the entire plot. If nothing, no background. (Color or Nothing)

• plot_padding: How much padding should be put around the plot as a whole (Measure)

• grid_color: Color of grid lines. (Color or Nothing)

• grid_color_focused: In the D3 backend, mousing over the plot makes the grid lines emphasised by transitioning to this color. (Color or Nothing)

• grid_line_width: Width of grid lines. (Measure)

• minor_label_font: Font used for minor labels such as guide entries and labels. (String)

• minor_label_font_size: Font size used for minor labels. (Measure)

• minor_label_color: Color used for minor labels. (Color)

• major_label_font: Font used for major labels such as guide titles and axis labels. (String)

• major_label_font_size: Font size used for major labels. (Measure)

• major_label_color: Color used for major labels. (Color)

• key_position: Where key should be placed relative to the plot panel. One of :left, :right, :top, :bottom, or :none. Setting to :none disables the key. (Symbol)

• key_title_font: Font used for titles of keys. (String)

• key_title_font_size: Font size used for key titles. (Measure)

• key_title_color: Color used for key titles. (Color)

• key_label_font: Font used for key entry labels. (String)

• key_label_font_size: Font size used for key entry labels. (Measure)

• key_label_color: Color used for key entry labels. (Color)

• key_max_columns: Maximum number of columns for key entry labels. (Int)

• bar_spacing: Spacing between bars in Geom.bar. (Measure)

• boxplot_spacing: Spacing between boxplots in Geom.boxplot. (Measure)

• errorbar_cap_length: Length of caps on error bars. (Measure)

• highlight_width: Width of lines drawn around plot geometry like points, and boxplot rectangles. (Measure)

• discrete_highlight_color and continuous_highlight_color: Color used to outline plot geometry. This is a function that alters (e.g. darkens) the fill color of the geometry. (Function)

• lowlight_color: Color used to draw background geometry, such as Geom.ribbon. This is a function that alters the fill color of the geometry. (Function)

• lowlight_opacity: Opacity of background geometry such as Geom.ribbon. (Float64)

• middle_color: Color altering function used to draw the midline in boxplots. (Function)

• middle_width: Width of the middle line in boxplots. (Measure)

• guide_title_position: One of :left, :center, :right indicating the placement of the title of color key guides. (Symbol)

• colorkey_swatch_shape: The shape used in color swatches in the color key guide. Either :circle or :square (Symbol)

• bar_highlight: Color used to stroke bars in bar plots. If a function is given, it's used to transform the fill color of the bars to obtain a stroke color. (Function, Color, or Nothing)

• discrete_color_scheme: A DiscreteColorScale see Scale.color_discrete_hue

• continuous_color_scheme: A ContinuousColorScale see Scale.color_continuous

Examples

dark_panel = Theme(
    panel_fill="black",
    default_color="orange"
)

plot(x=rand(10), y=rand(10), dark_panel)

Setting the font to Computer Modern to create a LaTeX-like look, and choosing a font size:

Gadfly.push_theme(dark_panel)

p = plot(x=rand(10), y=rand(10),
     style(major_label_font="CMU Serif",minor_label_font="CMU Serif",
           major_label_font_size=16pt,minor_label_font_size=14pt))

# can plot more plots here...

Gadfly.pop_theme()

Same effect can be had with with_theme

Gadfly.with_theme(dark_panel) do

  plot(x=rand(10), y=rand(10),
       style(major_label_font="CMU Serif",minor_label_font="CMU Serif",
             major_label_font_size=16pt,minor_label_font_size=14pt))
end

or

Gadfly.push_theme(dark_panel)

Gadfly.with_theme(
       style(major_label_font="CMU Serif",minor_label_font="CMU Serif",
             major_label_font_size=16pt,minor_label_font_size=14pt)) do

  plot(x=rand(10), y=rand(10))

end

Gadfly.pop_theme()

Named themes

To register a theme by name, you can extend Gadfly.get_theme(::Val{:theme_name}) to return a Theme object.

Gadfly.get_theme(::Val{:orange}) =
    Theme(default_color="orange")

Gadfly.with_theme(:orange) do
  plot(x=[1:10;], y=rand(10), Geom.bar)
end

Gadfly comes built in with 2 named themes: :default and :dark. You can also set a theme to use by default by setting the GADFLY_THEME environment variable before loading Gadfly.

The Dark theme

This is one of the two themes the ship with Gadfly the other being :default. Here are a few plots that use the dark theme.

Gadfly.push_theme(:dark)

plot(dataset("datasets", "iris"),
    x="SepalLength", y="SepalWidth", color="Species", Geom.point)

using RDatasets

gasoline = dataset("Ecdat", "Gasoline")

plot(gasoline, x=:Year, y=:LGasPCar, color=:Country,
         Geom.point, Geom.line)

using DataFrames

xs = 0:0.1:20

df_cos = DataFrame(
    x=xs,
    y=cos.(xs),
    ymin=cos.(xs) .- 0.5,
    ymax=cos.(xs) .+ 0.5,
    f="cos"
)

df_sin = DataFrame(
    x=xs,
    y=sin.(xs),
    ymin=sin.(xs) .- 0.5,
    ymax=sin.(xs) .+ 0.5,
    f="sin"
)

df = vcat(df_cos, df_sin)
p = plot(df, x=:x, y=:y, ymin=:ymin, ymax=:ymax, color=:f, Geom.line, Geom.ribbon)

using Distributions

X = rand(MultivariateNormal([0.0, 0.0], [1.0 0.5; 0.5 1.0]), 10000);
plot(x=X[1,:], y=X[2,:], Geom.hexbin(xbincount=100, ybincount=100))

Gadfly.pop_theme()

Gadfly.Theme(RGB{N0f8}(0.996,0.263,0.396),0.9mm,0.45mm,1.8mm,Function[Compose.circle,Gadfly.square,Gadfly.diamond,Gadfly.cross,Gadfly.xcross,Gadfly.utriangle,Gadfly.dtriangle,Gadfly.star1,Gadfly.star2,Gadfly.hexagon,Gadfly.octagon,Gadfly.hline,Gadfly.vline],0.3mm,:solid,RGB{N0f8}(0.133,0.157,0.192),nothing,1.0,RGB{N0f8}(0.133,0.157,0.192),5.0mm,RGB{N0f8}(0.341,0.341,0.341),Measures.Length{:mm,Float64}[0.5mm,0.5mm],RGB{N0f8}(0.627,0.627,0.627),0.2mm,"'PT Sans Caption','Helvetica Neue','Helvetica',sans-serif",2.822222222222222mm,RGB{N0f8}(0.631,0.631,0.631),"'PT Sans','Helvetica Neue','Helvetica',sans-serif",3.880555555555555mm,RGB{N0f8}(0.631,0.631,0.631),"'PT Sans Caption','Helvetica Neue','Helvetica',sans-serif",2.822222222222222mm,RGB{N0f8}(0.298,0.251,0.294),"'PT Sans','Helvetica Neue','Helvetica',sans-serif",3.880555555555555mm,RGB{N0f8}(0.631,0.631,0.631),"'PT Sans','Helvetica Neue','Helvetica',sans-serif",2.822222222222222mm,RGB{N0f8}(0.631,0.631,0.631),40,-0.05mm,1.0mm,3.0mm,Gadfly.default_stroke_color,0.3mm,Gadfly.border_color,Gadfly.default_continuous_highlight_color,Gadfly.lowlight_color,0.6,Gadfly.default_middle_color,0.6mm,:left,:square,:right,nothing,2.0mm,1000,10.0,0.5,0.2,4,Gadfly.Scale.DiscreteColorScale(Gadfly.gen_dark_colors,nothing,nothing,true),Gadfly.Scale.ContinuousColorScale(Gadfly.Scale.f,Gadfly.Scale.ContinuousScaleTransform(identity,identity,Gadfly.Scale.identity_formatter),nothing,nothing))