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Launch Interactive Fisheye Lens Explorer

Source: R/shiny_fisheye.R
shiny_fisheye.Rd

Launches an interactive Shiny application for exploring Focus–Glue–Context (FGC) fisheye lens transformations on geographic data. The app provides real-time lens positioning, adjustable distortion parameters, and side-by-side comparison of transformed and original views.

The application demonstrates fisheye effects on Victoria, Australia Local Government Areas (LGAs) with a network of healthcare facilities and aged care connections. Users can drag the lens to any position and adjust parameters without server-side re-rendering for smooth, responsive interaction.

Usage

shiny_fisheye(...)

Arguments

...

Additional arguments passed to shiny::runApp(). Common options include:

  • launch.browser: Logical or function to handle app launch (default = TRUE)

  • port: Integer port number (default = random available port)

  • host: Character host IP address (default = "127.0.0.1")

  • display.mode: Character display mode, "auto", "normal", or "showcase"

Value

Invisible NULL. The function is called for its side effect of launching the Shiny application. The R session will be blocked until the app is stopped (press Escape or close the browser window).

Details

Features

  • Interactive lens dragging: Click and drag anywhere on the map to reposition the fisheye lens in real-time

  • Parameter controls: Adjust inner radius (focus), outer radius (glue), zoom factor, and squeeze factor

  • Facility sampling: Randomly sample healthcare facilities and residential aged care facilities (RACFs) with adjustable sample size

  • Transfer visualization: Toggle display of patient transfer connections between facilities

  • Side-by-side comparison: Compare fisheye-transformed and original static views

Requirements

The Shiny app requires the following suggested packages:

  • shiny

  • tidyr

  • dplyr

  • purrr

  • ggthemes

If any are missing, install with:

install.packages(c("shiny", "tidyr", "dplyr", "purrr", "ggthemes"))

Implementation Notes

The app uses client-side JavaScript for smooth lens dragging without server round-trips. Fisheye transformations match the mathematical implementation in fisheye_fgc() and sf_fisheye(), applied to polygons, lines, and points in real-time using SVG rendering.

See also

Examples

if (FALSE) { # \dontrun{
# Launch the app with default settings
shiny_fisheye()

# Launch in browser on specific port
shiny_fisheye(launch.browser = TRUE, port = 8080)

# Launch in RStudio Viewer pane
shiny_fisheye(launch.browser = rstudioapi::viewer)
} # }