geomtext and geomlabel

geom_text() adds text labels to a plot. Text labels are useful for annotating data points, adding titles to specific regions, or displaying values directly on the plot. geom_label() is similar but is intended to display text with a background rectangle (note: background rectangle is not yet implemented in TidierPlots).

Arguments

• plot::GGPlot (optional): a plot object to add this geom to. This is typically used to facilitate creating your ggplot as part of a @chain.
• data (DataFrame): Data to use for this geom. If not provided, the geom will inherit the data from ggplot.
• aes(...): the names of the columns in the DataFrame that will be used in the mapping
• inherit_aes: should the geom inherit aes from the ggplot?
• ...: options that are not mapped to a column (passed to Makie.Text)

Text Alignment

Use the align argument to control text positioning relative to the (x, y) coordinates. Specify a tuple of horizontal and vertical alignment:

• Horizontal: :left, :center, :right
• Vertical: :top, :center, :bottom

For example, align = (:left, :bottom) positions text so that (x, y) is at the bottom-left corner of the text.

Required Aesthetics

• x
• y
• text (can be provided as aesthetic or argument)

Optional Aesthetics (see aes)

• color / colour

Optional Arguments

• color / colour: text color
• colormap / palette: colormap for colored text
• align: tuple of (horizontal, vertical) alignment (e.g., (:left, :bottom))
• font: font family (e.g., :bold, :italic)
• fontsize: size of text
• rotation: angle of rotation in radians
• justification: text justification
• strokewidth: outline width
• strokecolor: outline color
• glowwidth / glow: glow effect width
• glowcolor / glowcolour: glow effect color
• word_wrap_width: maximum width before wrapping
• alpha

using TidierPlots
using TidierData
using DataFrames

penguins = penguins_data();

Basic Text Labels

Create a simple plot with text at specified positions:

df = DataFrame(
    x = [1, 1, 2, 2],
    y = [1, 2, 1, 2],
    t = ["A", "B", "C", "D"]
)

ggplot(df, @aes(x = x, y = y, text = t)) +
    geom_text()

Add color based on the text value:

ggplot(df, @aes(x = x, y = y, text = t, color = t)) +
    geom_text()

Combining with Points

Text labels work well with points to label data:

ggplot(df, @aes(x = x, y = y, color = t)) +
    geom_point(size = 20) +
    geom_text(@aes(text = t), fontsize = 24, align = (:left, :bottom)) +
    lims(x = (0, 3), y = (0, 3))

Font Styling

Customize font size, style, and color:

ggplot(df, @aes(x = x, y = y, text = t)) +
    geom_text(fontsize = 30, font = :bold, color = :steelblue)

Text Alignment

Control where the text appears relative to the point:

ggplot(df, @aes(x = x, y = y)) +
    geom_point(size = 15) +
    geom_text(@aes(text = t), fontsize = 20, align = (:center, :bottom)) +
    lims(x = (0.5, 2.5), y = (0.5, 2.5))

Different alignment options:

ggplot(df, @aes(x = x, y = y)) +
    geom_point(size = 15) +
    geom_text(@aes(text = t), fontsize = 20, align = (:left, :center)) +
    lims(x = (0.5, 2.5), y = (0.5, 2.5))

Labeling Real Data

Label species on a scatterplot (using summarized data):

import Statistics: mean

species_centroids = @chain penguins begin
    @group_by(species)
    @summarize(
        bill_length_mm = mean(bill_length_mm),
        bill_depth_mm = mean(bill_depth_mm)
    )
end

ggplot(penguins, @aes(x = bill_length_mm, y = bill_depth_mm)) +
    geom_point(@aes(color = species), alpha = 0.5) +
    geom_text(data = species_centroids, @aes(text = species),
        fontsize = 20, font = :bold)

Text with Outline

Use strokewidth and strokecolor for better visibility:

ggplot(df, @aes(x = x, y = y, text = t)) +
    geom_text(fontsize = 40, strokewidth = 2, strokecolor = :black, color = :white)

Rotated Text

Use the rotation argument (in radians):

ggplot(df, @aes(x = x, y = y, text = t)) +
    geom_text(fontsize = 30, rotation = pi/4)

geom_label

geom_label() works the same as geom_text(). Note that the background rectangle feature is not yet implemented:

ggplot(df, @aes(x = x, y = y, text = t, color = t)) +
    geom_label(fontsize = 24)

Combining label with points:

ggplot(df, @aes(x = x, y = y, color = t)) +
    geom_label(@aes(text = t), fontsize = 24, align = (:left, :bottom), font = :bold) +
    geom_point() +
    lims(x = (0, 3), y = (0, 3))

Practical Example: Annotating Bar Charts

summary_df = @chain penguins begin
    @group_by(species)
    @summarize(count = n())
end

ggplot(summary_df, @aes(x = species, y = count)) +
    geom_col() +
    geom_text(@aes(text = count), fontsize = 20, align = (:center, :bottom))

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