brocks: The Personal R Functions of Brendan Rocks

#' Add a watermark to a plot
#'
#' @param png_path A path to a valid png file to use for the watermark
#'
#' @export
geom_watermark <- function(png_path = Sys.getenv("WATERMARK_PNG")){
  # Insert something to write the rasterGrob to a variable within the package
  # and just use that, if it exists (otherwise, load from disk)

  img <- png::readPNG(png_path)
  g   <- grid::rasterGrob(img, interpolate=TRUE)
  ggplot2::annotation_custom(g, xmin=-Inf, xmax=Inf, ymin=-Inf, ymax=Inf)
}

# #' Brendan's ggplot2 theme
# #'
# #' Currently, pretty half-baked!
# #'
# #' @export
# theme_br <- function(){
#   # You should :: this up once you're happy with it
#   requireNamespace("ggplot2")
#   theme_bw() +
#     theme(
#       legend.position    = "top",
#       text = element_text(family = "Ubuntu"),
#       strip.text.x       = element_text(family = "Ubuntu", colour = 'white'),
#       legend.background  = element_rect(fill=scales::alpha('white', 0)),
#       strip.background   = element_rect(colour ="#FFFFFF",  fill = "#424142")
#     )
# }

#' ggplot2 categorical colour hues
#'
#' Generate the colours which \code{ggplot2} would, given a certain number of
#' categories.
#'
#' @param n The number of colours to return
#'
#' @author John Colby (taken from: \url{https://stackoverflow.com/questions/8197559/emulate-ggplot2-default-color-palette})
#' @export
#' @examples
#' barplot(1:10, col = gg_colour_hue(10))
gg_colour_hue <- function(n) {
  hues = seq(15, 375, length=n+1)
  grDevices::hcl(h=hues, l=65, c=100)[1:n]
}

# #' Add a footnote to a ggplot chart
# #'
# #' Currently, the text wrapping is based on the plot's default font size (which
# #' is usually 12pts), meaning that using something smaller (as is the default in
# #' this function), is likely to result in text which is slightly more narrow
# #' than the available horizontal space. I don't mind it. Someone smarter than I
# #' might be able to fix it with splitTextGrob!
# #'
# #' @param p A ggplot2 plot object
# #' @param text The text used for the footnote
# #' @param detect_font for ggplot2 objects, should the function attempt to
# #'   extract the default font used?
# #' @param wrap Should line breaks be added to the text to (attempt) to prevent
# #'   it overflowing?
# #' @param newlines Should a new line be appended to the start and end of the
# #'   string, for spacing?
# #' @param fontface Passed to \code{\link{gpar}}
# #' @param fontsize Passed to \code{\link{gpar}}
# #' @param col Passed to \code{\link{gpar}}
# #' @param fontfamily Passed to \code{\link{gpar}}
# #' @param ... Passed to \code{\link{gpar}}
# #' @author Brendan Rocks \email{rocks.brendan@@gmail.com}, but heavily inspired
# #'   by  Wendi (Alan) Wang: \url{http://statmodeling.com/best-way-to-add-a-footnote-to-a-plot-created-with-ggplot2.html}
# #' @export
# #' @examples
# #' \dontrun{
# #'   # Let's make a simple plot and add a footnote to it.
# #'
# #'   # Some footnote text, taken from the 'fortunes' package
# #'   footnote <- "R is Open Source and so you can modify it to emulate the bugs in other software: that is not one of the aims of its developers so please don't expect us to do so for you.\n  -- Brian D. Ripley (answering a request for a change to Excel-like non IEC 60559 standard conform rounding)\n     R-help (March 2009)"
# #'
# #'   # A ggplot2 chart
# #'   library(ggplot2)
# #'   d <- data.frame(mtcars)
# #'   p <- ggplot(d, aes(cyl, mpg)) +
# #'   geom_point() +
# #'   theme(text = element_text(family = "Garamond"))
# #'
# #'   # Let's add our footnote!
# #'   g <- gg_footnote(p, footnote)
# #'   g
# #'
# #'   # Note that the text is horizontally truncated. It will take up the full
# #'   # width if we use the default ggplot2 font size of 12pts
# #'   g <- gg_footnote(p, foot_note, fontsize = 12)
# #'   g
# #' }
# gg_footnote <- function(p, text = "This is a footnote", detect_font = TRUE,
#                         wrap = TRUE, newlines = TRUE, fontface = "italic",
#                         fontsize = 8, col = "grey50", fontfamily = NULL, ...){
#
#   if(detect_font)
#     fontfamily <- p$theme$text$family
#
#   if(newlines)
#     text <- paste0("\n", text, "\n")
#
#   if(wrap)
#     text <- RGraphics::splitString(text)
#
#   gridExtra::arrangeGrob(
#     p,
#     bottom = grid::textGrob(
#       text, x = 0.05, hjust = 0, vjust = 0.5,
#       gp = grid::gpar(fontface = fontface, fontsize = fontsize, col = col,
#                       fontfamily = fontfamily, ...))
#   )
# }
#