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Significance-table annotations for ggplot2 discrete x-axes

Source: R/geom-sig-table.R
geom_sig_table.Rd

Helpers to add significance labels and optional brackets to ggplot2 plots from a user-supplied comparison table.

Returns an object that can be added directly to a ggplot with +.

Usage

geom_sig_table(
  p_table,
  y_npc,
  group1_col = "group1",
  group2_col = "group2",
  label_col = "significance",
  x_levels = NULL,
  facet_cols = NULL,
  draw_brackets = TRUE,
  bracket_tip_npc = 0.015,
  bracket_margin_npc = 0.02,
  text_size_pt = NULL,
  star_y_npc_offset = -0.05,
  text_family = NULL,
  text_face = NULL,
  text_colour = "black",
  bracket_colour = "black",
  bracket_linewidth = 0.2,
  bracket_linetype = 1,
  bracket_lineend = "round",
  vjust = 0
)

Arguments

p_table

A data frame containing at minimum group1, group2, and significance columns.

y_npc

Numeric vector of label y positions in npc coordinates.

group1_col, group2_col, label_col

Column names in p_table.

x_levels

Optional character vector giving x-axis order.

facet_cols

Optional character vector naming the facet columns in p_table. If NULL, they are auto-detected.

draw_brackets

Logical; whether brackets should be drawn.

bracket_tip_npc

Length of bracket tips in npc units.

bracket_margin_npc

Gap between label and bracket top line in npc units.

text_size_pt

Text size in points. Defaults to theme text size minus 2.

star_y_npc_offset

Upward offset, in npc units, applied only to star-only labels like "*", "**", "***".

text_family, text_face, text_colour

Text styling parameters.

bracket_colour, bracket_linewidth, bracket_linetype

Bracket styling.

bracket_lineend

Line ending for bracket segments. Defaults to "round".

vjust

Vertical justification for text.

Value

An object that can be added to a ggplot with +.

Details

Notes:

  • Facet-aware: if p_table contains facet columns matching the plot facets, annotations are placed only in matching panels. Otherwise they are repeated across all panels.

  • PDF-safe significance stars: star-only labels like "", "", "" remain ASCII and are nudged upward slightly so they sit more like "ns".

  • Bracket segment ends default to lineend = "round".