R/interactive_plot.R

In mosaicCalc: R-Language Based Calculus Operations for Teaching

#' Make an interactive plotly plot of a function of two variables
#'
#' An interactive plot lets you interrogate the plot to get
#' numerical values at each point. When `type = "surface"`, the
#' plot can be rotated to see the "shape" of the function from
#' various perspectives. Using the  interactive controls, you
#' can save the plot as a PNG file. But it's not possible to overlay
#' plots the way you can with `contourPlot()`.
#'
#' @param formula a formula describing a function in  the manner
#' of `mosaicCalc::makeFun()`
#' @param domain  a call to the `domain()` function giving ranges
#' using the same independent variables as in the `formula`
#' @param npts The fineness at which to evaluate the function specified
#' by the formula in the  plot. Default: 50
#' @param type Plot type: `"surface"`,  `"contour"`, `"both"`, or `"heatmap"`
#'
#' @examples \dontrun{
#' interactive_plot(
#'     sin(fred*ginger) ~ fred + ginger,
#'     domain(fred=range(0,pi),
#'            ginger = range(0, pi)),
#'     type = "both")
#' }
#'
#' @importFrom plotly plot_ly
#' @export
surface_plot <- function(formula, domain=c(-5,5),  npts=50,
                         type = c("both", "surface", "contour", "heatmap")) {
  type <- match.arg(type) # make sure it's one of the available choices
  Eval_list <- eval_as_vector_and_matrix(formula, domain, n = npts)

  if (type == "both") {
    plotly::plot_ly(x = Eval_list$x,
                    y = Eval_list$y,
                    z = Eval_list$.output.,
                    opacity = 0.7) %>%
      plotly::add_surface(
        contours = list(z=list(show=TRUE, usecolormap=TRUE,
                               highlightcolor="#ff0000",
                               project = list(z=TRUE)))
      )
  } else {
      plotly::plot_ly(x = Eval_list$x,
                  y = Eval_list$y,
                  z = Eval_list$.output.,
                  type = type)
  }

}
#' @rdname surface_plot
#' @export
interactive_plot <- surface_plot

#' @rdname surface_plot
#' @export
surface_with_contours <- function(formula, domain=c(-5,5), npts=50) {
  Eval_list <- eval_as_vector_and_matrix(formula, domain, n = npts)
  plotly::plot_ly(x = Eval_list$x,
                  y = Eval_list$y,
                  z = Eval_list$.output.,
                  opacity = 0.7) %>%
    plotly::add_surface(
      contours = list(z=list(show=TRUE, usecolormap=TRUE,
                             highlightcolor="#ff0000",
                             project = list(z=TRUE)))
    )

}