Plot Eye Density

Draws a fixation density map on the shared eyesim density scale. Zero density is transparent, so a background stimulus shows through, and the map keeps the aspect ratio of its coordinate grid. Over a `bg_image`, thin white contour lines at five evenly spaced levels (from zero to the upper limit or the map's maximum) keep density edges visible.

Usage

# S3 method for class 'eye_density'
plot(
  x,
  alpha = 0.8,
  bg_image = NULL,
  transform = c("identity", "sqroot", "curoot", "rank"),
  colours = NULL,
  legend = TRUE,
  limits = NULL,
  ...
)

Arguments

x

An "eye_density" object.

alpha

Maximum opacity of the density layer (default: 0.8); lower densities are progressively more transparent.

bg_image

An optional image file name (or `cimg`) to use as the background.

transform

The transformation to apply to the density values (default: c("identity", "sqroot", "curoot", "rank")).

colours

Optional vector of colours for the density ramp (default: the eyesim density ramp).

legend

Whether to show the density colour bar (default: `TRUE`).

limits

Optional density limits for the colour scale (default: from zero to the map's maximum). Give several maps the same `limits` to compare them on one scale.

...

Additional args

Value

A ggplot object representing the eye density plot.

See also

Other visualization: anim_scanpath(), element_text_wrap(), eyesim_colours(), plot.fixation_group(), scale_fill_eyesim_density(), theme_eyesim()

Examples

# Create a fixation group and compute eye density
fg <- fixation_group(x = c(100, 200, 300), y = c(100, 150, 200),
                     onset = c(0, 200, 400), duration = c(200, 200, 200))
ed <- eye_density(fg, sigma = 50, xbounds = c(0, 400), ybounds = c(0, 300))
# Plot the eye density
plot(ed)