R/EventLong.R

In sascha2schroeder/popEye: Analysis of eye-tracking data from reading experiments

# NOTE: to be used with output of TimestampToEvent() with eyelink = T

EventLong <- function(out) {
  
  if (sum(out$sac$start > 0) == 0) {
    tmplong <- rbind(out$sac)
    return(tmplong)
  } else {
    out2 <- out
    
    out2$sac$msg <- "SAC"
    out2$fix$msg <- "FIX"
    
    if (nrow(out2$blink) > 0) {
      out2$blink$msg <- "BLINK"
    }
    
    # re-assign fixatons with NA to blinks
    for (i in 1:nrow(out2$fix)) {
      if (is.na(out2$fix$xs[i]) == T) {
        out2$blink <- rbind(out2$blink, out2$fix[i, ])
        out2$fix <- out2$fix[-i, ]
      }
    }
    
    # re-assign blink message
    if (nrow(out2$blink) > 0) {
      out2$blink$msg <- "BLINK"
    }
    
    # combine  
    tmplong <- rbind(out2$sac, out2$fix, out2$blink)
    tmplong <- tmplong[order(tmplong$start), ]
    
    
    # screen for empty events
    # ------------------------
    
    tmplong$dur <- tmplong$stop - tmplong$start
    tmplong <- tmplong[tmplong$dur > 0, ]
    tmplong$dur <- NULL
    
    
    # integrate BLINK and SAC
    # ------------------------
    
    # NOTE: assumes that first event is not BLINK
    
    tmplong$del <- 0
    for (i in 1:nrow(tmplong)) {
      if (tmplong$msg[i] == "BLINK") {
        if (i == 1) next # FIX
        tmplong$start[i] <- tmplong$start[i - 1]
        tmplong$stop[i] <- tmplong$stop[i - 1]
        tmplong$xs[i] <- tmplong$xs[i - 1]
        tmplong$ys[i] <- tmplong$ys[i - 1]
        tmplong$xe[i] <- tmplong$xe[i - 1]
        tmplong$ye[i] <- tmplong$ye[i - 1]
        tmplong$del[i - 1] <- 1
      }
    }
    tmplong <- tmplong[tmplong$del == 0, ]
    tmplong$del <- NULL
    tmplong$num <- 1:nrow(tmplong)
    
    
    # compute blinks
    # ---------------
    
    tmplong$blink.before <- 0
    tmplong$blink.after <- 0
    
    for (i in 1:nrow(tmplong)) {
      if (tmplong$msg[i] == "BLINK") {
        tmplong$blink.after[i - 1] <- 1
        if (is.na(tmplong$msg[i + 1]) == F) {
          tmplong$blink.before[i + 1] <- 1  
        }
      }
    }
    
    # combine 
    tmplong$blink <- 0
    tmplong$blink[tmplong$blink.before == 1 | tmplong$blink.after == 1] <- 1
    
    tmplong$blink.before <- NULL
    tmplong$blink.after <- NULL
    
    return(tmplong) 
    
  }

}