R/fabric_shape_add.R

In statunizaga/fabricerin: Create Easily Canvas in 'shiny' and 'RMarkdown' Documents

#' Add a shape object to a preexisting canvas element
#'
#' @param cid the id of the canvas element you want to add your shape to
#' @param shapeId the id of the shape object
#' @param shape the shape of the object. Choices include 'Circle', 'Triangle' and 'Rect'. Defaults to 'Rect'
#' @param left the shape's position from the left relative to the canvas element. Defaults to 100
#' @param top the shape's position from the top relative to the canvas element. Defaults to 100
#' @param fill the color of the shape. Defaults to 'red'
#' @param width the width of the shape. Defaults to 200
#' @param height the height of the shape. Defaults to 200
#' @param angle the angle of rotation of the shape. Defaults to 0 (no rotation)
#' @param opacity the opacity of the shape. Defaults to 1
#' @param strokecolor the stroke color of the shape. Defaults to 'darkblue'
#' @param strokewidth the stroke width of the shape. Defaults to 5.
#' @param selectable logical. If TRUE, the user can modify interactively the shape. Defaults to TRUE
#' @param radius Mandatory if the chosen shape is a 'Circle'. Defaults to NULL
#'
#' @return a shape object inside a preexisting canvas element
#' @export
#'
#' @examples
#'
#' if (interactive()) {
#'
#' ui <- fluidPage(
#'
#' use_fabric(),
#'
#' fabric_shape(cid = "canvas",
#'              shapeId = "shape1",
#'              shape = "Rect",
#'              left = 130,
#'              top = 200),
#'
#' fabric_shape_add(cid = "canvas",
#'                  shapeId = "shapo",
#'                  shape = "Circle",
#'                  radius = 30,
#'                  left = 100,
#'                  top = 100),
#'
#' fabric_shape_add(cid = "canvas",
#'                  shapeId = "shapa",
#'                  shape = "Circle",
#'                  radius = 30,
#'                  left = 200,
#'                  top = 100),
#'
#' fabric_shape_add(cid = "canvas",
#'                  shapeId = "shapox",
#'                  shape = "Circle",
#'                  radius = 30,
#'                  left = 300,
#'                  top = 100),
#'
#' fabric_shape_add(cid = "canvas",
#'                  shapeId = "shapor",
#'                  shape = "Circle",
#'                  radius = 30,
#'                  left = 300,
#'                  top = 100)
#'
#' )
#'
#'
#' server <- function(input, output) {}
#'
#' shinyApp(ui = ui, server = server)
#'
#' }



fabric_shape_add <- function(cid,
                             shapeId,
                             shape = "Rect",
                             left = "100",
                             top = "100",
                             fill = "red",
                             width = 200,
                             height = 200,
                             angle = 0,
                             opacity = 1,
                             strokecolor = "darkblue",
                             strokewidth = 5,
                             selectable = TRUE,
                             radius = NULL){


  if (!shape %in% c("Rect",
                    "Circle",
                    "Triangle")) {
    stop(paste0(shape, " shape is not available, choices are Rect, Circle and Triangle"))
  }


  if (shape == "Circle" &
      is.null(radius)) {
    stop("If you draw a Circle, you need to provide a radius")
  }


  radius <- ifelse(!is.null(radius), glue::glue("radius:{radius}"), "")

  selectable <- ifelse(selectable == TRUE, "true", "false")

  htmltools::tags$script(htmltools::HTML(glue::glue(
    "

var {shapeId} = new fabric.{shape}({{

left: {left},

top: {top},

fill: '{fill}',

width: {width},

height: {height},

angle: {angle},

opacity: {opacity},

stroke: '{strokecolor}',

strokeWidth: {strokewidth},

selectable: {selectable},

{radius}

}});

{cid}.add({shapeId});


  "
  )))


}