Preview the grid layout of a SeqPlotR plot — seq_preview

Renders a schematic toy representation of the intended plot layout — no data required. Each track region is drawn as a filled, labeled rectangle. Useful for verifying a layout string or operator chain before adding data.

Usage

seq_preview_layout(
  plot_obj = NULL,
  layout = NULL,
  labels = TRUE,
  colors = NULL,
  margins = TRUE,
  margin_size = 0.05
)

Arguments

plot_obj: A seq_plot object built with the operator chain, or NULL. If provided, the layout is extracted from the object.
layout: A multiline layout string (e.g. "##AA\n##AA\nBBBC\nBBBD"), or NULL. Used when plot_obj is not provided.
labels: Logical. If TRUE (default), draw the track ID label centered in each region.
colors: Optional named character vector mapping track IDs to fill colors (e.g. c(A = "#FF0000", B = "#00FF00")). Unspecified IDs receive automatic colors.
margins: Logical. If TRUE (default), draw a thin border rectangle indicating the outer canvas margin.
margin_size: Numeric in the range 0 to 0.5. Fractional canvas margin on each side. Default 0.05.

Value

A named list of npc bounding boxes (invisibly): each element is list(x0, x1, y0, y1) keyed by track ID.

Examples

if (FALSE) { # \dontrun{
# Preview a patchwork layout string directly
layout <- "
##AA
##AA
BBBC
BBBD
"
seq_preview_layout(layout = layout)

# Preview a layout built with operators
p <- seq_plot() |>
  (\(x) x %|% seq_track(track_id = "Signal",  track_width = 3))() |>
  (\(x) x %|% seq_track(track_id = "Ideogram", track_width = 1))() |>
  (\(x) x %__% seq_track(track_id = "Genes"))()
seq_preview_layout(plot_obj = p)
} # }