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Build the Shiny iframe bridge JavaScript for a draggable helper

Source: R/spatial_io.R
dragmapr_iframe_bridge.Rd

Returns the JavaScript needed to pass region and label offset state from the draggable helper iframe back into Shiny inputs via postMessage, and to poll the iframe until state arrives. The string is suitable for wrapping in tags$head(tags$script(HTML(...))).

Usage

dragmapr_iframe_bridge(
  region_input = "region_csv",
  label_input = "label_csv",
  slow_poll_ms = 2000L,
  fast_poll_ms = 500L,
  allowed_origin = "same-origin",
  iframe_selector = "iframe"
)

Arguments

region_input

Name of the Shiny input that receives the region-offset CSV text. Defaults to "region_csv".

label_input

Name of the Shiny input that receives the label-offset CSV text. Defaults to "label_csv".

slow_poll_ms

Polling interval in milliseconds once initial state has been received. Defaults to 2000.

fast_poll_ms

Polling interval in milliseconds before initial state arrives. Defaults to 500.

allowed_origin

Origin allowed to send drag state messages. Use "same-origin" to accept the current Shiny app origin, "*" to accept any origin, or a specific origin such as "https://example.com".

iframe_selector

CSS selector used to find the drag-map helper iframe in the parent document. Defaults to "iframe" (first iframe found), but a more specific selector such as "#my-helper-frame" or "iframe.studio-helper-frame" is recommended when the page may contain other iframes (e.g. Shiny download handlers).

Value

A character string of JavaScript ready for tags$head(tags$script(HTML(dragmapr_iframe_bridge()))).

Examples

# In a Shiny UI:
if(interactive()){
library(shiny)
ui <- fluidPage(
  tags$head(tags$script(HTML(
    dragmapr_iframe_bridge(iframe_selector = "#my-helper-frame")
  ))),
  uiOutput("helper")  # render tags$iframe(id = "my-helper-frame", ...)
)
}