R/ternary.legend.R

In trifield: Some basic facilities for ternary fields and plots

ternary.legend <-
function(x0 = 0.2, y0 = 0.8, radius = 0.1,
                          lab1 = 'A', lab2 = 'B', lab3 = 'C',
                          infl = 1.5, cex = 0.75, length = 0.05, ...)
{
	lx = 2 / sqrt(3)
	x1 = x0
	y1 = y0 + radius
	arrows(x0, y0, x1, y1, length = length, ...)
	y1 = y0 + infl * radius
	text(x1, y1, lab1, cex = cex)
	x1 = x0 - radius * cos(pi / 6)
	y1 = y0 - radius * sin(pi / 6)
	arrows(x0, y0, x1, y1, length = length, ...)
	x1 = x0 - infl * radius * cos(pi / 6)
	y1 = y0 - infl * radius * sin(pi / 6)
	text(x1, y1, lab2, cex = cex)
	x1 = x0 + radius * cos(pi / 6)
	y1 = y0 - radius * sin(pi / 6)
	arrows(x0, y0, x1, y1, length = length, ...)
	x1 = x0 + infl * radius * cos(pi / 6)
	y1 = y0 - infl * radius * sin(pi / 6)
	text(x1, y1, lab3, cex = cex)
}