Plot Fixations (gaze data), as for pre-analytic screening

fixation-plot.R

library(tidyverse)
library(ggplot2)
library(cowplot)

## make some data. Assume display screen stimulus display of 1024x768
n <- 2000 # n fixations

lx <- 512-200
rx <- 512+200
cx <- 512
sdx  <-  100

my <- 768/2
sdy <- 150

set.seed(1234)

L <- tibble(x=rnorm(n=n, m=lx, sd=sdx),
            y=rnorm(n=n, m=my, sd=sdy))

R <- tibble(x=rnorm(n=n, m=rx, sd=sdy))

C <- tibble(x=rnorm(n=n*.3, m=cx, sd=sdx*.33),
            y=rnorm(n=n*.3, m=my, sd=sdy*.33))

df <- bind_rows(R, L, C)

df %>%
    ggplot(aes(x=x, y=y)) +
    geom_point(size=2, alpha=.1, fill=NA) + # low values of size and alpha help see through overplotting
    annotate(geom="rect", xmin=0, xmax=1024, ymin=0, ymax=768, fill=NA, color="black") + ## display screen rect
    geom_hline(aes(yintercept=768/2), color="grey70", size=1) +
    geom_vline(aes(xintercept=1024/2), color="grey70", size=1) +
    scale_x_continuous(limits=c(0,1024), oob=scales::squish) + ## squish forces offscreen fixations to be included in plot
    scale_y_continuous(limits=c(768,0), oob=scales::squish, trans="reverse") + ## origin for most eye-trackers is UL corner
#    theme_nothing() +
    theme_cowplot()