graphShade <- function(x,y, col.line, breaks, shade=TRUE, col.shade=col.line, ... ) {
  # Initialize
  nb = length(breaks)
  plot(x,y, type="n", ...)

  # Plot the lines
  part = which(x<=breaks[1])
  lines(x[part],y[part], col=col.line[1])
  for(i in 2:nb) {
    part = which(x<=breaks[i] & x>breaks[i-1])
    lines(x[part],y[part], col=col.line[i])
  }
  part = which(x>breaks[nb])
  lines(x[part],y[part], col=col.line[nb+1])


  if(shade) {  # Shade the areas ?
    part = which(x<=breaks[1])
    polyx = c(x[part],rev(x[part]))
    polyy = c(y[part],rep(0,length(part)))
    polygon(polyx,polyy,col=col.shade[1],border=col.line[1])
    for(i in 2:nb) {
      part = which(x<=breaks[i] & x>breaks[i-1])
      polyx = c(x[part],rev(x[part]))
      polyy = c(y[part],rep(0,length(part)))
      polygon(polyx,polyy,col=col.shade[i],border=col.line[i])
    }
    part = which(x>breaks[nb])
    polyx = c(x[part],rev(x[part]))
    polyy = c(y[part],rep(0,length(part)))
    polygon(polyx,polyy,col=col.shade[nb+1],border=col.line[nb+1])
  }

}