I am releasing the version 1.1 of pROC.

The lines.roc family of functions allows to add a ROC curve to an existing plot with lines. Until now you had to use plot with add = TRUE. More informations with ?lines.roc. For instance:

library(pROC)
data(aSAH)
rocs100 <- roc(aSAH$outcome, aSAH$s100)
rocwfns <- roc(aSAH$outcome, aSAH$wfns)

plot(rocs100)
lines(rocwfns)

Two additions were made to the plot.roc function. First the type argument, which is directly forwarded to par, allows to change the line type. print.auc.col allows to change the color of the printed AUC independently from the ROC curve. Here is an example of what you can do now:

plot(rocs100, print.auc=TRUE, print.auc.col="blue", type="o")

Here is the full change log:

• Added lines.roc functions for ROC.
• Added type argument for both lines.roc and plot.roc.
• Added print.auc.col argument to plot.roc.
• Fixed a warning in roc.test.default when the class of predictor1 had several elements.
• Fixed an encoding failure during the checks on MacOS X (R only).

You can find the new version on ExPASy and on the CRAN. To update, type update.packages() or install.packages("pROC") if you want to update pROC only.