Add nearestPOI.R

Author: davebraze

DESCRIPTION

@@ -1,8 +1,8 @@
 Package: FDBeye
 Type: Package
 Title: Functions to Ease Work with Eyetracker Data
-Version: 0.0.19
-Date: 2016-10-25
+Version: 0.0.20
+Date: 2017-06-28
 Authors@R: c(
     person("David", "Braze", email="davebraze@gmail.com", role=c("aut", "cre")),
     person("Tao", "Gong", role="aut"),
@@ -20,6 +20,7 @@ Imports:
     grid,
     plyr,
     png,
+    purrr,
     stats,
     stringr,
     tools,
@@ -35,7 +36,7 @@ License: MIT + file LICENSE
 LazyData: true
 URL: https://github.com/davebraze/FDBeye
 BugReports: https://github.com/davebraze/FDBeye/issues
-RoxygenNote: 5.0.1
+RoxygenNote: 6.0.1
 Suggests:
     knitr,
     rmarkdown

NAMESPACE

@@ -17,6 +17,7 @@ export(get_xybounds)
 export(inked)
 export(makeReport)
 export(mark_oob)
+export(nearestPOI)
 export(readELascii)
 export(reg2regdef)
 export(regdef2ias)

R/nearestPOI.R

@@ -0,0 +1,40 @@
+##' @title Find the nearest Point of Interest for each fixation.
+##'
+##' @description For each fixation in a fixation report, this function
+##'     will determine the nearest Point of Interest and the
+##'     fixation's distance from that Point of Interest.
+##'
+##' @details For each fixation in a fixation report, this function
+##'     will determine the nearest Point of Interest and the
+##'     fixation's distance from that Point of Interest.
+##'
+##'     The value of \code{supplement} determines whether to return
+##'     the POI values within an enriched version of \code{fixReport},
+##'     or as a simple two column data.frame.
+##'
+##' @param fixReport A fixation Report as may be created by
+##'     fixReport(). Must contain columns \code{xpos} and \code{ypos}.
+##' @param poiList A data.frame containing x,y coordinates for Points
+##'     of Interest. The data.frame must contain exactly two columns,
+##'     named \code{xpos} and \code{ypos}, in that order.
+##' @param supplement If TRUE, nearestPOI() will return a data.frame
+##'     consisting of fixReport suplemented with columns nearestpoi
+##'     and dist2poi. If FALSE return a 2 column data.frame with just
+##'     those two columns.
+##' @return A data.frame including columns nearestpoi and dist2poi.
+##' @author Dave Braze <davebraze@@gmail.com>
+##' @export
+nearestPOI <- function (fixReport, poiList, supplement=TRUE) {
+    f <- function(fix=fix, poiList=poiList) {
+        ## Find nearest poi for one fixation.
+        tmp <- rbind(fix[c("xpos", "ypos")], poi) ## should merge rather than rbind
+        dst <- as.matrix(dist(tmp))[-1,1]
+        .nearestpoi <- which.min(dst)
+        names(.nearestpoi) <- NULL
+        .dist2poi <- min(dst)
+        retval <- data.frame(nearestpoi=.nearestpoi, dist2poi=.dist2poi)
+    }
+    retval <- purrr::by_row(fixReport, f, poi=poi, .collate="row",
+                            .labels=supplement)
+    select(retval, -matches("^.row$"))
+}