Set up persistent manual plot layout edits across re-renders

VizModules plots are fully rebuilt on every input change, which would normally discard any layout tweaks a user made by hand: dragging the legend, moving or editing annotations, repositioning the (draggable) axis titles, or sliding a continuous-colour legend (colorbar). setup_manual_edits() together with its companion finalize_manual_edits() add this persistence to a plotting module with two short lines of wiring, so manually repositioned elements survive subsequent rebuilds.

Usage

setup_manual_edits(input, session, plot_source)

Arguments

input: The module's input object.
session: The module's session object.
plot_source: Character scalar. A unique plotly event source id for this module instance, typically session$ns("<plot-type>") (e.g. session$ns("scatter")). It scopes the captured plotly_relayout events to this plot and must match the plot_source later passed to finalize_manual_edits().

Value

A list (the "edit store") to hand to finalize_manual_edits(), with components:

edits: A shiny::reactiveValues() holding the captured legend, annotations, and colorbar edits.
rendered_fig: A shiny::reactiveVal() holding the most recently rendered figure, used to map relayout annotation indices to stable, rebuild-proof keys.

Details

Call setup_manual_edits() once, near the top of your module's shiny::moduleServer() body, so the observers it registers belong to the module's reactive domain. It creates a reactive store and registers the observers that capture plotly_relayout events (legend, annotation, and axis-title drags) plus the JavaScript-forwarded colorbar drag. Then, inside your plotly::renderPlotly(), pass the freshly built figure through finalize_manual_edits() before returning it.

Module wiring (three steps)

myPlotServer <- function(id, data) {
    moduleServer(id, function(input, output, session) {
        # 1. Unique event source + edit store (once, near the top).
        plot_source <- session$ns("myplot")
        edit_store <- setup_manual_edits(input, session, plot_source)

        output$myPlot <- renderPlotly({
            # 2. Create your plotly plot
            fig <- build_my_plotly_figure(data(), input)
            # 3. Finalize on the rebuilt figure, then return it.
            finalize_manual_edits(fig, plot_source, edit_store, session)
        })
    })
}

Author

Jared Andrews

Examples

if (FALSE) { # \dontrun{
# Call once inside a module server's moduleServer() body:
plot_source <- session$ns("myplot")
edit_store <- setup_manual_edits(input, session, plot_source)
} # }