make_alignment_dummies() helps you to visually align genes across molecules that have been faceted with a free x scale. The output of this function is a data frame of dummy genes. If these dummy genes are added to a 'ggplot2' plot with ggplot::geom_blank(), they will extend the x axis range in such a way that the start or end of a selected gene is visually aligned across the facets.

make_alignment_dummies(data, mapping, on, side = "left")



Data frame of genes. This is almost certainly the same data frame that will later be passed to ggplot2::ggplot().


Aesthetic mapping, created with ggplot2::aes(). Must contain the following aesthetics: xmin, xmax, y, and id (a unique identifier for each gene).


Name of gene to be visually aligned across facets. This gene must be present in 'data', in the column mapped to the id aesthetic.


Should the visual alignment be of the 'left' (default) or 'right' side of the gene?


dummies <- make_alignment_dummies(example_genes, ggplot2::aes(xmin = start,
  xmax = end, y = molecule, id = gene), on = "genE")

ggplot2::ggplot(example_genes, ggplot2::aes(xmin = start, xmax = end,
    y = molecule, fill = gene)) +
  geom_gene_arrow() +
  ggplot2::geom_blank(data = dummies) +
  ggplot2::facet_wrap(~ molecule, scales = "free", ncol = 1)