R/plotROCframe.R

In jvanheld/stats4bioinfo: Utilities for the book "Statistics for bioinformatics"

################################################################
## Plot an empty frame for the ROC curve:
## - axes from 0 to 1
## - diagonals
## - grid every 0.1
#' @title Plot an empty frame to draw a ROC curve
#' @author Jacques van Helden (\email{Jacques.van-Helden@@univ-amu.fr})
#' @description Plot an empty frame to draw a ROC curve
#' @details
#' First version: 2015-04
#' Last modification: 2015-04
#' @param main="ROC curve"  Main title for the plot
#' @param xlab="False Positive Rate (FPR)"  Label for the abcsissa
#' @param ylab="True Positive Rate (TPR)" Label for the ordinate
#' @param xlim=c(0,1)  Limits for the abcsissa
#' @param ylim=c(0,1)  Limits for the ordinates
#' @param grid.bars=seq(from=0,to=1,by=0.1) Grid bars
#' @param plot.limits=TRUE Plot a black rectangle with the limits.
#' @param plot.diagonal=TRUE Plot the diagonal to indicate random expectation.
#' @param ... Additional parameters are passed to plot().
#' @export
plotROCframe <- function(main="ROC curve",
                         xlab="FPR",
                         ylab="Sensitivity",
                         xlim=c(0,1),
                         ylim=c(0,1),
                         grid.bars = seq(from=0,to=1,by=0.1),
                         plot.limits=TRUE,
                         plot.diagonal=TRUE,
                         ...) {
  
  ## Plot the frame
  plot(0, 
       0, 
       xlab=xlab, 
       ylab=ylab, 
       xlim=xlim, 
       ylim=ylim, 
       type="n",
       main=main, ...)
  
  ## Plot grid every 10%
  abline(v=grid.bars,col="#DDDDDD")
  abline(h=grid.bars,col="#DDDDDD")
  
  ## Plot limits
  if (plot.limits) {
    abline(h=0:1,col="#888888")
    abline(v=0:1,col="#888888")
  }
  
  ## Highlight the diagonal
  if (plot.diagonal) {
    abline(a=0,b=1,col="#888888")
    #  abline(a=1,b=-1,col="#BBBBBB")
  }
}