[R] Gantt chart problem after upgrade to R 2.4.0

[Jim Lemon]

John Kane wrote:
> I am having a problem with a  gantt  chart since
> moving to R2.4.0. from 2.3.1
> ...

Okay, I think I have fixed the problem. I don't yet know why it worked 
on Windows and not Linux, but this should work on both. I have added 
another argument to the gantt.chart function and it seems to overcome 
the problem. Haven't tested it extensively, so I would appreciate any 
information about bugs that have sprung from the ichor of the one I 
squashed. There will be another version of plotrix shortly and this will 
be in it.

Jim

Watch out for the line breaks that have crept into the code.

gantt.chart<-function(x=NULL,format="%Y/%m/%d",xlim=NULL,taskcolors=NULL,
  priority.legend=FALSE,vgridpos=NULL,vgridlab=NULL,vgrid.format="%Y/%m/%d",
  half.height=0.25,hgrid=FALSE,main="",ylab="") {

  oldpar<-par(no.readonly=TRUE)
  if(is.null(x)) x<-get.gantt.info(format=format)
  ntasks<-length(x$labels)
  plot.new()
  charheight<-strheight("M",units="inches")
  maxwidth<-max(strwidth(x$labels,units="inches"))*1.5
  if(is.null(xlim)) xlim=range(c(x$starts,x$ends))
  npriorities<-max(x$priorities)
  if(is.null(taskcolors))
   taskcolors<-color.gradient(c(255,0),c(0,0),c(0,255),npriorities)
  else {
   if(length(taskcolors) < npriorities)
    taskcolors<-rep(taskcolors,length.out=npriorities)
  }
  bottom.margin<-ifelse(priority.legend,0.5,0)
  par(mai=c(bottom.margin,maxwidth,charheight*5,0.1))
  par(omi=c(0.1,0.1,0.1,0.1),xaxs="i",yaxs="i")
  plot(x$starts,1:ntasks,xlim=xlim,ylim=c(0.5,ntasks+0.5),
   main="",xlab="",ylab=ylab,axes=FALSE,type="n")
  box()
  if(nchar(main)) mtext(main,3,2)
  if(is.null(vgridpos)) tickpos<-axis.POSIXct(3,xlim,format=vgrid.format)
  else tickpos<-vgridpos
  # if no tick labels, use the grid positions if there
  if(is.null(vgridlab) && !is.null(vgridpos))
   vgridlab<-format.POSIXct(vgridpos,vgrid.format)
  # if vgridpos wasn't specified, use default axis ticks
  if(is.null(vgridlab)) axis.POSIXct(3,xlim,format=vgrid.format)
  else axis(3,at=tickpos,labels=vgridlab)
  topdown<-seq(ntasks,1)
  axis(2,at=topdown,labels=x$labels,las=2)
  abline(v=tickpos,col="darkgray",lty=3)
  for(i in 1:ntasks) {
   rect(x$starts[i],topdown[i]-half.height,
   x$ends[i],topdown[i]+half.height,
   col=taskcolors[x$priorities[i]],
   border=FALSE)
  }
  if(hgrid)
 
abline(h=(topdown[1:(ntasks-1)]+topdown[2:ntasks])/2,col="darkgray",lty=3)
  if(priority.legend) {
   par(xpd=TRUE)
   plim<-par("usr")
   gradient.rect(plim[1],0,plim[1]+(plim[2]-plim[1])/4,0.3,col=taskcolors)
   text(plim[1],0.2,"Priorities  ",adj=c(1,0.5))
   text(c(plim[1],plim[1]+(plim[2]-plim[1])/4),c(0.4,0.4),c("High","Low"))
  }
  par(oldpar)
  invisible(x)
}