The R Project SVN R

contour <-
function (x = seq(0, 1, len = nrow(z)), y = seq(0, 1, len = ncol(z)),
      z,
      nlevels = 10, levels = pretty(zlim, nlevels),
      xlim = range(x, finite = TRUE),
          ylim = range(y, finite = TRUE),
      zlim = range(z, finite = TRUE),
      labcex = 0,
      col = par("fg"), lty = par("lty"), add = FALSE, ...)
{
    ## labcex is disregarded since we do NOT yet put  ANY labels...
    if (missing(z)) {
    if (!missing(x)) {
        if (is.list(x)) {
        z <- x$z; y <- x$y; x <- x$x
        } else {
        z <- x
        x <- seq(0, 1, len = nrow(z))
        }
    } else stop("no `z' matrix specified")
    } else if (is.list(x)) {
    y <- x$y
    x <- x$x
    }
    if (any(diff(x) <= 0) || any(diff(y) <= 0))
    stop("increasing x and y values expected")
    if (!is.matrix(z) || nrow(z) <= 1 || ncol(z) <= 1)
    stop("no proper `z' matrix specified")
    if (!add) {
    plot.new()
    plot.window(xlim, ylim, "")
    title(...)
    }
    ##- don't lose  dim(.)
    if (!is.double(z)) storage.mode(z) <- "double"
    .Internal(contour(as.double(x), as.double(y), z, as.double(levels),
              col = col, lty = lty))
    if (!add) {
    axis(1)
    axis(2)
    box()
    }
    invisible()
}