library(rggobi)
library(scagnostics)

.GGobiCall <- getNamespace("rggobi")$.GGobiCall

 ggobi_display_set_tour_projection <- 
function (gd, value) 
{
    normal <- all(colSums(value^2) - 1 < 0.001)
    orthog <- all(crossprod(value, value) - diag(ncol(value)) < 
        0.001)
    if (!normal) 
        stop("Matrix is not normal (colSums do not equal 1)")
    if (!orthog) 
        stop("Matrix is not orthogonal")
    invisible(.GGobiCall("setTourProjection", gd, pmode(gd), 
        value))
}

 ggobi_display_get_tour_projection <- 
function (gd) 
{
    mat <- .GGobiCall("getTourProjection", gd, pmode(gd))
    mat[, 1:2]
}

getproj <- function(p, x=NULL) {
	pp <- rnorm(p)
	if (length(x) > 0) {
		pp <- pp - crossprod(x,pp)*x
	}

	return(pp/sqrt(crossprod(pp)))
}

proj <- function(df) {
	df <- as.matrix(df)
	cols <- ncol(df)
	pp1 <- getproj(cols)
	pp2 <- getproj(cols, pp1)

#	plot(df %*% pp1, df %*% pp2)
	return(cbind(pp1,pp2))
}

ortho <- function(x) {
	pp1 <- x[,1]/sqrt(crossprod(x[,1]))
	pp2 <- x[,2] - crossprod(x[,2],pp1)*pp1
	pp2 <- pp2/sqrt(crossprod(pp2))
	return(cbind(pp1,pp2))
}