violin

Makie.violin Function

violin(x, y)

Draws a violin plot which consists of pairs of density plots draw side by side. The density pairs can be sourced from the same or from different data.

Arguments

• x: positions of the categories

• y: variables whose density is computed

Plot type

The plot type alias for the violin function is Violin.

source

Examples

using CairoMakie
categories = rand(1:3, 1000)
values = randn(1000)

violin(categories, values)

using CairoMakie
fig = Figure()
xs = vcat([fill(i, i * 1000) for i in 1:4]...)
ys = vcat(randn(6000), randn(4000) * 2)
for (i, scale) in enumerate([:area, :count, :width])
    ax = Axis(fig[i, 1])
    violin!(ax, xs, ys; scale, show_median=true)
    Makie.xlims!(0.2, 4.8)
    ax.title = "scale=:$(scale)"
end
fig

using CairoMakie
categories = rand(1:3, 1000)
values = map(categories) do x
    return x == 1 ? randn() : x == 2 ? 0.5 * randn() : 5 * rand()
end

violin(categories, values, datalimits = extrema)

using CairoMakie
N = 1000
categories = rand(1:3, N)
dodge = rand(1:2, N)
side = rand([:left, :right], N)
color = @. ifelse(side === :left, :orange, :teal)
values = map(side) do s
    return s === :left ? randn() : rand()
end

violin(categories, values, dodge = dodge, side = side, color = color)

using CairoMakie
N = 1000
categories = rand(1:3, N)
side = rand([:left, :right], N)
color = map(categories, side) do x, s
    colors = s === :left ? [:red, :orange, :yellow] : [:blue, :teal, :cyan]
    return colors[x]
end
values = map(side) do s
    return s === :left ? randn() : rand()
end

violin(categories, values, side = side, color = color)

Using statistical weights

using CairoMakie
using Distributions

N = 100_000
categories = rand(1:3, N)
values = rand(Uniform(-1, 5), N)

w = pdf.(Normal(), categories .- values)

fig = Figure()

violin(fig[1,1], categories, values)
violin(fig[1,2], categories, values, weights = w)

fig

Horizontal axis

using CairoMakie
fig = Figure()

categories = rand(1:3, 1000)
values = randn(1000)

ax_vert = Axis(fig[1,1];
    xlabel = "categories",
    ylabel = "values",
    xticks = (1:3, ["one", "two", "three"])
)
ax_horiz = Axis(fig[1,2];
    xlabel="values", # note that x/y still correspond to horizontal/vertical axes respectively
    ylabel="categories",
    yticks=(1:3, ["one", "two", "three"])
)

# Note: same order of category/value, despite different axes
violin!(ax_vert, categories, values) # `orientation=:vertical` is default
violin!(ax_horiz, categories, values; orientation=:horizontal)

fig

Attributes

bandwidth

Defaults to automatic

Kernel density bandwidth, determined automatically if automatic.

boundary

Defaults to automatic

Boundary of the density estimation, determined automatically if automatic.

clip_planes

Defaults to @inherit clip_planes automatic

Clip planes offer a way to do clipping in 3D space. You can set a Vector of up to 8 Plane3f planes here, behind which plots will be clipped (i.e. become invisible). By default clip planes are inherited from the parent plot or scene. You can remove parent clip_planes by passing Plane3f[].

color

Defaults to @inherit patchcolor

Sets the color of violin plots. Can be given per data point to set the color for individual violins or densities. For this the color within each data set must be consistent.

cycle

Defaults to [:color => :patchcolor]

Sets which attributes to cycle when creating multiple plots. The values to cycle through are defined by the parent Theme. Multiple cycled attributes can be set by passing a vector. Elements can

• directly refer to a cycled attribute, e.g. :color

• map a cycled attribute to a palette attribute, e.g. :linecolor => :color

• map multiple cycled attributes to a palette attribute, e.g. [:linecolor, :markercolor] => :color

datalimits

Defaults to (-Inf, Inf)

Specify values to trim the violin. Can be a Tuple or a Function (e.g. datalimits=extrema).

depth_shift

Defaults to 0.0

Adjusts the depth value of a plot after all other transformations, i.e. in clip space, where -1 <= depth <= 1. This only applies to GLMakie and WGLMakie and can be used to adjust render order (like a tunable overdraw).

dodge

Defaults to automatic

Dodge can be used to separate violins drawn at the same x position/category. For this each violin is given an integer value corresponding to its position relative to the given x positions. E.g. with positions = [1, 1, 1, 2, 2, 2] we have 3 violins at each position which can be separated by dodge = [1, 2, 3, 1, 2, 3].

dodge_gap

Defaults to 0.03

Sets the gap between dodged violins relative to their size.

fxaa

Defaults to true

Adjusts whether the plot is rendered with fxaa (fast approximate anti-aliasing, GLMakie only). Note that some plots implement a better native anti-aliasing solution (scatter, text, lines). For them fxaa = true generally lowers quality. Plots that show smoothly interpolated data (e.g. image, surface) may also degrade in quality as fxaa = true can cause blurring.

gap

Defaults to 0.2

Size of the gap between violins. The modified width is width * (1 - gap).

inspectable

Defaults to @inherit inspectable

Sets whether this plot should be seen by DataInspector. The default depends on the theme of the parent scene.

inspector_clear

Defaults to automatic

Sets a callback function (inspector, plot) -> ... for cleaning up custom indicators in DataInspector.

inspector_hover

Defaults to automatic

Sets a callback function (inspector, plot, index) -> ... which replaces the default show_data methods.

inspector_label

Defaults to automatic

Sets a callback function (plot, index, position) -> string which replaces the default label generated by DataInspector.

max_density

Defaults to automatic

Sets the maximum density value to which violin plots are scaled.

mediancolor

Defaults to @inherit linecolor

Sets the color of the median line.

medianlinewidth

Defaults to @inherit linewidth

Sets the width of the median line.

model

Defaults to automatic

Sets a model matrix for the plot. This overrides adjustments made with translate!, rotate! and scale!.

n_dodge

Defaults to automatic

Sets the maximum integer for dodge. This sets how many violins can be placed at a given position, controlling their width.

npoints

Defaults to 200

Number of points used per density plot.

orientation

Defaults to :vertical

Orientation of the violins (:vertical or :horizontal)

overdraw

Defaults to false

Controls if the plot will draw over other plots. This specifically means ignoring depth checks in GL backends

scale

Defaults to :area

Scale density by area (:area), count (:count), or width (:width).

show_median

Defaults to false

Show median as midline.

side

Defaults to :both

Specify :left or :right to only plot the density on one side of the violin. This can be set for each data point to source the left and right densities from different data sets.

space

Defaults to :data

Sets the transformation space for box encompassing the plot. See Makie.spaces() for possible inputs.

ssao

Defaults to false

Adjusts whether the plot is rendered with ssao (screen space ambient occlusion). Note that this only makes sense in 3D plots and is only applicable with fxaa = true.

strokecolor

Defaults to @inherit patchstrokecolor

Sets the outline color of violins or densities (if sampled separately). This requires strokewidth > 0.

strokewidth

Defaults to @inherit patchstrokewidth

Sets the width of the outline of violins or densities (if sampled separately).

transformation

Defaults to :automatic

Controls the inheritance or directly sets the transformations of a plot. Transformations include the transform function and model matrix as generated by translate!(...), scale!(...) and rotate!(...). They can be set directly by passing a Transformation() object or inherited from the parent plot or scene. Inheritance options include:

• :automatic: Inherit transformations if the parent and child space is compatible

• :inherit: Inherit transformations

• :inherit_model: Inherit only model transformations

• :inherit_transform_func: Inherit only the transform function

• :nothing: Inherit neither, fully disconnecting the child's transformations from the parent

Another option is to pass arguments to the transform!() function which then get applied to the plot. For example transformation = (:xz, 1.0) which rotates the xy plane to the xz plane and translates by 1.0. For this inheritance defaults to :automatic but can also be set through e.g. (:nothing, (:xz, 1.0)).

transparency

Defaults to false

Adjusts how the plot deals with transparency. In GLMakie transparency = true results in using Order Independent Transparency.

visible

Defaults to true

Controls whether the plot gets rendered or not.

weights

Defaults to automatic

Vector of statistical weights (length of data). By default, each observation has weight 1.

width

Defaults to automatic

Sets the width of the bounding box of each violin. When dodge is used this sets combined width of all dodged violins in a single category/x value.