R/render.venn.diagram.R

In publicus/r-veccompare: Perform Set Operations on Vectors, Automatically Generating All n-Wise Comparisons, and Create Markdown Output

#' Render (Print) a Previously-Computed Venn Diagram
#'
#' A wrapper function for printing a \code{grid}-based image using \code{grid::grid.draw()}.
#'
#' @param venn_diagram_created_with_VennDiagram_package A grid-based diagram object. For example, a Venn diagram previously generated using \code{veccompare::compare.vectors()}.
#' @param viewport_npc_width_height_for_images The scale at which to print an image. If the image is cut off at its edges, for example, this can be set lower than 1.0.
#'
#' @return The function will not return a value; rather, it will print the image.
#' @export render.venn.diagram
#'
#' @examples
#' # Create comparisons across 5 vectors, specifically creating all 4-way venn diagrams from them:
#' example <- veccompare::compare.vectors(
#'   veccompare::example.vectors.list[1:5],
#'   draw_venn_diagrams = TRUE,
#'   suppress_messages = TRUE,
#'   degrees_of_comparison_to_include = 4
#' )
#'
#' # Get the first 4-way comparison that includes a diagram:
#' diagram <- veccompare::extract.compared.vectors(
#'   example,
#'   degrees_of_comparison = 4,
#'   elements_of_output = "venn_diagram"
#' )[[1]]$venn_diagram
#'
#' # Print the diagram:
#' veccompare::render.venn.diagram(
#'   diagram,
#'   viewport_npc_width_height_for_images = .7
#'      # Scale the image down to 70%,
#'      # in case it otherwise gets cut off at the margins.
#' )
render.venn.diagram <- function(
	venn_diagram_created_with_VennDiagram_package,
	viewport_npc_width_height_for_images = 1.0
){
	grid::grid.newpage()
	grid::pushViewport(grid::viewport(
		width = grid::unit(viewport_npc_width_height_for_images, "npc"),
		height = grid::unit(viewport_npc_width_height_for_images, "npc")
	)) # Following https://stackoverflow.com/questions/21234439/how-to-force-the-labels-to-fit-in-venndiagram#comment75690400_22826211, force the output rendering mechanism to be smaller than normal, in order not to cut off diagram names.
	grid::grid.draw(venn_diagram_created_with_VennDiagram_package)
}