Animated phylomorphospace projection

The so-called 'phylomorphospace' is a projection of the tree into phenotypic space for quantitative traits. Consequently, I thought it might be fun to try & animate this projection - that is, to visualize the transformation of the tree from the way it's typically projected into a phylomorphospace.

This could look something like the following:

project.phylomorphospace<-function(tree,X,nsteps=1000,sleep=0,...){
    tree<-minRotate(reorder(tree,"cladewise"),X[,2],print=FALSE)
    X<-X[tree$tip.label,]
    A<-cbind(fastAnc(tree,X[,1]),fastAnc(tree,X[,2]))
    cladogram<-tree
    cladogram$edge.length<-NULL
    mar<-par()$mar
    plotTree(cladogram,type="cladogram",nodes="centered",plot=FALSE)
    obj<-get("last_plot.phylo",envir=.PlotPhyloEnv)
    obj$xx<-obj$xx*(max(c(X[,1],A[,1]))-min(c(X[,1],A[,1])))+
        min(c(X[,1],A[,1]))
    xlim<-range(obj$xx)
    xlim[2]<-xlim[2]+max(strwidth(tree$tip.label))
    obj$yy<-(obj$yy-min(obj$yy))/(max(obj$yy)-min(obj$yy))*
        (max(c(X[,2],A[,2]))-min(c(X[,2],A[,2])))+min(c(X[,2],A[,2]))
    ylim<-range(obj$yy)
    X0<-cbind(obj$xx[1:Ntip(tree)],obj$yy[1:Ntip(tree)])
    rownames(X0)<-tree$tip.label
    A0<-cbind(obj$xx[1:tree$Nnode+Ntip(tree)],
        obj$yy[1:tree$Nnode+Ntip(tree)])
    rownames(A0)<-1:tree$Nnode+Ntip(tree)
    par(mar=mar)
    phylomorphospace(tree,X0,A0,label="horizontal",xlim=xlim,
        ylim=ylim,...)
    for(i in 1:nsteps){
        Sys.sleep(sleep)
        dev.hold()
        phylomorphospace(tree,((nsteps-i)*X0+i*X)/nsteps,
            ((nsteps-i)*A0+i*A)/nsteps,xlim=xlim,ylim=ylim,
                ...)
        dev.flush()
    }
}

And if we try it out:

library(phytools)
project.phylomorphospace(tree,X,xlab="",ylab="",
    node.size=c(0,1.2))

Kinda neat?

The .gif I generated as follows:

png(file="ppm-%04d.png",width=600,height=600,res=120)
par(mar=c(2.1,2.1,1.1,1.1))
project.phylomorphospace(tree,X,xlab="",ylab="",
    node.size=c(0,1),lwd=1,nsteps=100,fsize=0.6)
dev.off()
system("ImageMagick convert -delay 10 -loop 2 *.png 14Mar18c-post.gif")
file.remove(list.files(pattern=".png"))

Finally, here's how I simulated the tree & data:

tree<-pbtree(n=26,tip.label=LETTERS)
vcv<-matrix(c(1,-0.8,-0.8,1),2,2)
X<-sim.corrs(tree,vcv)