Curved arcs

plotk: draws an arc, optionally ending in an arrow, between each consecutive pair of points – a curved alternative to tda_pl_lines for showing a directed relationship without the line hiding what is under it. Fixed along the way: a genuine rendering bug where a shallow arc (TDA's technique for one – a small slice of a large-radius circle) was measured by the full circle's radius when sizing the plot, inflating the bounding box to fit an almost entirely off-screen circle and shrinking everything else into a corner; the fix (using the arc segment's actual extent) is general, not specific to this function.

Usage

tda_pl_arc(p, x, y, curvature = 0, arrow = NULL, lty = NULL, lw = NULL, ...)

Arguments

p

a tda_ps session.

x, y

coordinates the arcs connect, in order; at least two points.

curvature

how much the arc bows out, as a fraction of the distance between the two points; 0 is a straight line. TDA's own sc=.

arrow

size of an arrowhead at the end of each arc, as c(length, width) in mm; no arrowhead if not given.

lty, lw

line type and line width in mm for the arc.

...

further options for the command.

Value

The session, with the command added.

See also

Other plotting: plot.tda_ple(), tda_check_ps(), tda_pl(), tda_pl_axis(), tda_pl_graph(), tda_pl_hist, tda_pl_panel(), tda_pl_regression(), tda_pl_scatter(), tda_plot_ps(), tda_ps(), tda_ps3(), tda_read_ps()

Examples

p <- tda_ps(xlim = c(0, 10), ylim = c(0, 10))
p <- tda_pl_frame(p)
p <- tda_pl_arc(p, c(2, 8), c(2, 8), curvature = 3, arrow = c(1.5, 1))
plot(p)