Module refline 

Reference lines: geom_hline, geom_vline, geom_abline.

Each geom draws one line per row of its layer data when the matching aesthetic column is present (yintercept, xintercept, or slope/intercept — ggplot2’s data-mapped form, which also honours per-row color / linetype / alpha and facet panels), and otherwise falls back to the constant stored in the geom. As in ggplot2:

• xintercept / yintercept train the x / y position scale (the line is always inside the panel); slope / intercept train nothing;
• reference lines do not inherit the plot-level mapping (inherit.aes = FALSE);
• geom_abline lives in data space (in the scales’ transformed space for e.g. scale_x_log10), clipped to the panel.

Structs

GeomAbline

Line y = intercept + slope · x in data space, spanning the panel and clipped to it.

GeomHline

Horizontal reference line spanning the panel width.

GeomVline

Vertical reference line spanning the panel height.