Plot block constructors — new_plot

Blocks for data visualization using base R graphics can be created via new_plot_block().

Usage

new_plot_block(server, ui, class, ctor = sys.parent(), ...)

new_scatter_block(x = character(), y = character(), ...)

Arguments

server: A function returning shiny::moduleServer()
ui: A function with a single argument (ns) returning a shiny.tag
class: Block subclass
ctor: String-valued constructor name or function/frame number (mostly for internal use or when defining constructors for virtual classes)
...: Forwarded to new_plot_block() and new_block()
x, y: Columns to place on respective axes

Value

All blocks constructed via new_plot_block() inherit from plot_block.

Details

Due to the current block evaluation procedure, where block evaluation is separated from block "rendering" (via shiny::renderPlot()) integration of base R graphics requires some mechanism to achieve this decoupling. This is implemented by adding a plot attribute to the result of block_eval(), generated with grDevices::recordPlot() and containing the required information to re-create the plot at a later time. As part of block_output(), the attribute is retrieved and passed to grDevices::replayPlot(). Consequently, any block that inherits from plot_block is required to support this type of decoupling.

Scatter block

Mainly for demonstration purposes, this block draws a scattter plot using base::plot(). In its current simplistic implementation, apart from axis labels (fixed to the corresponding column names), no further plotting options are available and for any "production" application, a more sophisticated (set of) block(s) for data visualization will most likely be required.