Drive an already-rendered widget from the Shiny server

vellumwidget_proxy() is the server-to-client counterpart of the input read-back documented in vellumwidget-shiny. It returns a lightweight handle to a widget that is already on the page, so the server can change what the widget shows — set the selection, cross-filter it, zoom it — without re-rendering it (no renderVellumwidget() round-trip, no full redraw, no lost pan/zoom). This mirrors leaflet::leafletProxy() / DT::dataTableProxy() / plotly::plotlyProxy().

Usage

vellumwidget_proxy(outputId, session = NULL)

Arguments

outputId

The id of the vellumwidgetOutput() to control (the un-namespaced id, as passed to vellumwidgetOutput(); module namespacing is handled for you).

session

The Shiny session; defaults to the current reactive domain, so you rarely pass it explicitly.

Value

An object of class "vellumwidget_proxy" (invisibly from the verbs), to be piped into vw_select() and the other proxy verbs.

Details

Call it inside an observe() / observeEvent() with the same outputId you gave vellumwidgetOutput(), then pipe the handle through one or more of the verbs below. Each verb sends a single custom message to the browser and returns the proxy invisibly, so calls chain with the pipe.

vw_select()

Replace the widget's selection with keys (the element data_ids). Selecting projects across a mark's hover_group and propagates to any linked / crosstalk widgets, exactly as a user click would, and updates input$<id>_selected.

vw_clear_selection()

Clear the selection.

vw_filter()

Cross-filter: show only the elements whose key is in keys and dim/hide the rest (display tier — the data is untouched).

vw_clear_filter()

Remove the filter (show everything).

vw_zoom()

Zoom/pan the view to frame the elements in keys.

vw_reset_zoom()

Restore the original (full) view.

All keys are the element data keys — the data_id a vellumplot mark declares — the same identifiers you receive back through input$<id>_selected and friends.

See also

vw_select(), vw_filter(), vw_zoom(); vellumwidgetOutput() and vellumwidget-shiny for reading interactions back.

Examples

if (FALSE) { # \dontrun{
library(shiny)
server <- function(input, output, session) {
  output$plot <- renderVellumwidget(my_widget)
  # A server-side control drives the plot without redrawing it:
  observeEvent(input$highlight, {
    vellumwidget_proxy("plot") |> vw_select(input$highlight)
  })
  observeEvent(input$reset, {
    vellumwidget_proxy("plot") |> vw_clear_selection() |> vw_reset_zoom()
  })
}
} # }