R/geom_polygon_auc.R

In pROC: Display and Analyze ROC Curves

geom_polygon_auc <- function(data, ...) {
  UseMethod("geom_polygon_auc")
}

geom_polygon_auc.auc <- function(data, legacy.axes = FALSE, ...) {
  # Get the roc data with coords
  roc <- attr(data, "roc")
  roc$auc <- data
  df <- get.coords.for.ggplot(roc, ignore.partial.auc = FALSE)

  # Add bottom-right point
  partial.auc <- attr(data, "partial.auc")
  one.or.hundred <- ifelse(attr(data, "percent"), 100, 1)
  if (legacy.axes) {
    if (identical(partial.auc, FALSE)) {
      df[nrow(df) + 1, ] <- c(NA, one.or.hundred, 0, one.or.hundred)
    } else if (attr(data, "partial.auc.focus") == "sensitivity") {
      df[nrow(df) + c(1, 2), ] <- c(NA, NA, one.or.hundred, one.or.hundred, partial.auc, one.or.hundred, one.or.hundred)
    } else { # partial.auc.focus == "specificity"
      df[nrow(df) + c(1, 2), ] <- c(NA, NA, rev(partial.auc), 0, 0, one.or.hundred - rev(partial.auc))
    }
  } else {
    if (identical(partial.auc, FALSE)) {
      df[nrow(df) + 1, ] <- c(NA, 0, 0, 0)
    } else if (attr(data, "partial.auc.focus") == "sensitivity") {
      df[nrow(df) + c(1, 2), ] <- c(NA, NA, 0, 0, partial.auc, 0, 0)
    } else { # partial.auc.focus == "specificity"
      df[nrow(df) + c(1, 2), ] <- c(NA, NA, rev(partial.auc), 0, 0, one.or.hundred - rev(partial.auc))
    }
  }

  # Prepare the aesthetics
  aes <- get.aes.for.ggplot(attr(data, "roc"), legacy.axes)

  # Do the plotting
  ggplot2::geom_polygon(aes$aes, data = df, ...)
}

geom_polygon_auc.roc <- function(data, ...) {
  geom_polygon_auc(data$auc, ...)
}

geom_polygon_auc.smooth.roc <- geom_polygon_auc.roc