civilyticsR/R/logo.R

#' Plot a jpeg image as a raster
#'
#' @param path a character representing the relative or absolute path to the image
#' @param add a logical, TRUE to add the image to an existing plot, FALSE creates a new plot
#' @param upscale a logical, TRUE upscales the resolution of the graphic by a factor of 3, FALSE
#' preserves the resolution
#' @return a rasterImage
#' @export
#' @importFrom jpeg readJPEG
#' @importFrom graphics rasterImage
#' @examples
#' \dontrun{
#' img <- system.file("img","Knowles_Headshot_2019_good.jpg",package="civilytics")
#' plot_jpeg(img)
#' }
plot_jpeg <- function(path, add=FALSE, upscale = TRUE)
{
  jpg = readJPEG(path, native = TRUE) # read the file
  res = dim(jpg)[2:1] # get the resolution, [x, y]
  if (upscale){
    res <- res * 3
  }
  if (!add) # initialize an empty plot area if add==FALSE
    plot(1,1,xlim=c(1,res[1]),ylim=c(1,res[2]),asp=1,type='n',xaxs='i',yaxs='i',
         xaxt='n',yaxt='n',xlab='',ylab='',bty='n',  oma=c(0,0,1,1), mar=c(0,0,1,1)
    )
  rasterImage(jpg,1,1,res[1],res[2],interpolate=TRUE)
}


#' Plot a PNG file as a rasterGrob for inclusion in ggplot2
#'
#' @param filename a character with file path to a png file
#'
#' @return a plotted rasteGrob of a png image
#' @export
#' @importFrom png readPNG
#' @importFrom grid rasterGrob
get_png <- function(filename) {
  grid::rasterGrob(png::readPNG(filename), interpolate = TRUE)
}


#' Add a logo to a ggplot2 object
#'
#' @param plot a ggplot2 grob
#' @param logo a logo grob created by make_logo_grob()
#' @param margin_param a numeric specifying what margin to add or subtract to align the logo
#' @param font_scale Numeric. Multiplicative scaling factor applied to text
#'   sizes before composing the plot with the logo. Default `1.1` inflates
#'   text by ~10 \% to compensate for the viewport shrinkage caused by
#'   [gridExtra::arrangeGrob()]. Set to `1` to disable.
#' @param position Character. Corner placement for the logo: `"bottom-right"`
#'   (default), `"bottom-left"`, `"top-right"`, or `"top-left"`. Controls
#'   whether the logo is placed above or below the plot.
#'
#' @return a grob with a logo attached to it ready to plot
#' @importFrom ggplot2 theme
#' @importFrom gridExtra arrangeGrob
#' @export
add_logo <- function(plot, logo, margin_param = NULL, font_scale = 1.1,
                     position = c("bottom-right", "bottom-left",
                                  "top-right", "top-left")) {
  position <- match.arg(position)
  at_top <- grepl("top", position)

  # Inflate text sizes to compensate for arrangeGrob viewport shrinkage.
  # All theme text elements use rel() sizing, so scaling the root 'text'
  # element cascades to titles, axis labels, legends, captions, and strips.
  if (!is.null(font_scale) && font_scale != 1) {
    base_size <- plot$theme$text$size %||% 14
    plot <- plot + ggplot2::theme(
      text = ggplot2::element_text(size = base_size * font_scale)
    )
  }

  if (at_top) {
    # For top placement, tighten the top margin of the plot
    if (!is.null(margin_param)) {
      plot <- plot + theme(plot.margin = unit(c(margin_param, 7, 7, 7), "pt"))
    } else {
      plot <- plot + theme(plot.margin = unit(c(-14, 7, 7, 7), "pt"))
    }
    arrangeGrob(logo, plot, heights = c(0.1, 0.93),
                padding = unit(0.1, "line"))
  } else {
    # Bottom placement (original behaviour)
    if(has_caption(plot)) {
      cap_lines <- measure_caption(plot)
      if (!is.null(margin_param)) {
        plot <- plot + theme(plot.margin = unit(c(7, 7, margin_param, 7), "pt"))
      } else {
        plot <- plot + theme(plot.margin = unit(c(7, 7, cap_lines * -52, 7), "pt"))
      }
    } else {
      plot <- plot + theme(plot.margin = unit(c(7, 7, -14, 7), "pt"))
    }
    arrangeGrob(plot, logo, heights = c(0.93, 0.1),
                padding = unit(0.1, "line"))
  }
}

#' Measure a ggplot2 object caption
#'
#' @param gg a ggplot object
#'
#' @return a numeric value stating the number of lines to be added or subtracted to align a logo with
#' the caption
#' @importFrom stringr str_count
#' @export
#'
#' @examples
#' p1 <- ggplot2::ggplot(mtcars, ggplot2::aes(mpg, wt)) + ggplot2::geom_point()
#' measure_caption(p1) # Should equal 1 since no caption is present
measure_caption <- function(gg) {
  if (has_caption(gg)) {
    stringr::str_count(gg$labels$caption, pattern = "\n") + 1
  } else {
    1
  }
}


#' Test whether a ggplot2 object has a caption
#'
#' @param gg a gg object from ggplot2
#'
#' @return a logical, TRUE if a caption exists and FALSE if it does not
#' @import ggplot2
#' @export
#'
#' @examples
#' p1 <- ggplot2::ggplot(mtcars, ggplot2::aes(mpg, wt)) + ggplot2::geom_point()
#' has_caption(p1) # FALSE
has_caption <- function(gg) {
  any(names(gg$labels) == "caption")
}

#' Add a logo to multiple ggplot2 objects
#'
#' @param plot_list a list containing ggplot2 objects
#' @param logo a grob containing the logo created with `make_logo_grob`
#' @param nrow an integer, default = 1, for the number of rows to align the plots in
#' @param widths an optional vector the same length as plot_list with the widths for each plot
#' @param margin_param a number giving the adjustment up or down to help manually align logo and captions
#' @param font_scale Numeric. Multiplicative scaling factor applied to text
#'   sizes before composing. Default `1.1`. See [add_logo()] for details.
#'
#' @return a grid object
#' @note The resulting object needs to be drawn to the screen using grid.draw()
#' @importFrom gridExtra arrangeGrob
#' @importFrom ggplot2 theme
#' @importFrom grid grid.draw
#' @export
#'
#' @examples
#' \dontrun{
#' library(ggplot2); library(grid)
#' tmp_plot <- ggplot(mtcars) + aes(x = hp, y = disp) + geom_point() + theme_civilytics()
#' tmp_logo <- make_logo_grob()
#' plot_and_logo <- add_logo(tmp_plot, tmp_logo)
#' grid.draw(plot_and_logo)
#' dev.off()
#' }
add_logo_ga <- function(plot_list, logo, nrow = 1, widths = NULL,
                        margin_param = NULL, font_scale = 1.1) {
  # Inflate text sizes to compensate for viewport shrinkage
  if (!is.null(font_scale) && font_scale != 1) {
    plot_list <- lapply(plot_list, function(p) {
      base_size <- p$theme$text$size %||% 14
      p + ggplot2::theme(
        text = ggplot2::element_text(size = base_size * font_scale)
      )
    })
  }

  # Change position of logo depending on if plot has a caption
  if (!is.null(margin_param)) {
    margin <- theme(plot.margin = unit(c(7, 7, margin_param, 7), "pt"))
  } else if (any(unlist(lapply(plot_list, has_caption)))) {
    cap_lines <- max(sapply(plot_list, measure_caption))
    margin <- theme(plot.margin = unit(c(7, 7, -7 * sqrt(cap_lines), 7), "pt"))
  } else {
    margin <- theme(plot.margin = unit(c(7, 7, 7, 7), "pt"))
  }
  if (nrow > 1) {
    len <- length(plot_list)
    plot_list[[len]] <- plot_list[[len]] + margin
  } else {
    plot_list <- lapply(plot_list, "+", margin)
  }

  if (nrow != 1) {
    if (!is.null(widths)) warning("`widths` is ignored when `nrow > 1`")
    hold <- arrangeGrob(grobs = plot_list, nrow = nrow, ncol = 1)
  } else {
    hold <- arrangeGrob(grobs = plot_list, nrow = 1, ncol = length(plot_list), widths = widths)
  }

  arrangeGrob(hold, logo, heights = c(0.93, .07))
}


#' Get a Civilytics Logo grob
#'
#' Returns a ggplot object containing the Civilytics logo as a rasterGrob,
#' ready to compose with plots via [add_logo()], [add_logo_ga()], or the
#' pipe-friendly [civilytics_logo()].
#'
#' @param type Character. `"wordmark"` (default) uses the full wordmark.
#'   `"mark"` uses the compact C-pulse icon only.
#' @param variant Character. `"light"` (default) uses the dark logo for light
#'   backgrounds. `"dark"` uses the reverse (light) logo for dark backgrounds
#'   (pairs with [theme_civilytics_dark()]).
#' @param position Character. Corner placement for the logo: `"bottom-right"`
#'   (default), `"bottom-left"`, `"top-right"`, or `"top-left"`. Controls
#'   horizontal alignment of the logo grob.
#'
#' @return A ggplot object (class `"gg"`) containing the logo grob.
#' @export
#' @importFrom ggplot2 ggplot theme_void annotation_custom
#' @examples
#' logo <- make_logo_grob()                          # wordmark, light
#' logo <- make_logo_grob("mark", "dark")            # mark, dark
#' logo <- make_logo_grob(position = "bottom-left")  # left-aligned
#' class(logo)  # "gg" "ggplot"
make_logo_grob <- function(type = c("wordmark", "mark"),
                           variant = c("light", "dark"),
                           position = c("bottom-right", "bottom-left",
                                        "top-right", "top-left")) {
  type     <- match.arg(type)
  variant  <- match.arg(variant)
  position <- match.arg(position)

  img_file <- switch(
    paste(type, variant, sep = "_"),
    wordmark_light = "civilytics-wordmark.png",
    wordmark_dark  = "civilytics-wordmark-reverse.png",
    mark_light     = "civilytics-mark.png",
    mark_dark      = "civilytics-mark-reverse.png"
  )

  align_left <- grepl("left", position)

  if (align_left) {
    xmin <- 0
    xmax <- if (type == "mark") 0.07 else 0.35
  } else {
    xmin <- if (type == "mark") 0.93 else 0.65
    xmax <- 1
  }

  ggplot2::ggplot() +
    ggplot2::theme_void() +
    ggplot2::annotation_custom(
      get_png(system.file("img", img_file, package = "civilytics")),
      xmin = xmin, xmax = xmax
    )
}

#' Add a Civilytics logo to a ggplot (pipe-friendly)
#'
#' A convenience wrapper that creates the logo grob and attaches it to a
#' corner of the plot in one call. Designed for use with the base pipe `|>`.
#'
#' **Important:** R's `|>` has *higher* precedence than `+`, so you must
#' wrap the ggplot chain in parentheses before piping:
#'
#' ```
#' (ggplot(mpg, aes(displ, hwy)) +
#'   geom_point() +
#'   theme_civilytics()) |>
#'   civilytics_logo()
#' ```
#'
#' @param plot A ggplot object.
#' @param type Character. `"wordmark"` (default) or `"mark"`. Passed to
#'   [make_logo_grob()].
#' @param variant Character. `"light"` (default) or `"dark"`. Passed to
#'   [make_logo_grob()].
#' @param position Character. Corner placement for the logo: `"bottom-right"`
#'   (default), `"bottom-left"`, `"top-right"`, or `"top-left"`.
#' @param margin_param Numeric or `NULL`. Manual margin adjustment passed to
#'   [add_logo()].
#' @param font_scale Numeric. Inflate text sizes by this factor to compensate
#'   for viewport shrinkage when composing with [gridExtra::arrangeGrob()].
#'   Default `1.1` (~10 \% inflation). Set to `1` to disable.
#'
#' @return A grob (from [gridExtra::arrangeGrob()]) ready to draw with
#'   [grid::grid.draw()].
#' @export
#'
#' @examples
#' \dontrun{
#' library(ggplot2); library(grid)
#'
#' # Pipe usage — parentheses required around the ggplot chain
#' (ggplot(mpg, aes(displ, hwy)) +
#'   geom_point() +
#'   theme_civilytics()) |>
#'   civilytics_logo() |>
#'   grid.draw()
#'
#' # Top-right placement
#' (ggplot(mpg, aes(displ, hwy)) +
#'   geom_point() +
#'   theme_civilytics()) |>
#'   civilytics_logo(position = "top-right") |>
#'   grid.draw()
#'
#' # Bottom-left with mark
#' (ggplot(mpg, aes(displ, hwy)) +
#'   geom_point() +
#'   theme_civilytics()) |>
#'   civilytics_logo(type = "mark", position = "bottom-left") |>
#'   grid.draw()
#'
#' # Dark theme with mark in top-left
#' (ggplot(mpg, aes(displ, hwy)) +
#'   geom_point() +
#'   theme_civilytics_dark()) |>
#'   civilytics_logo(variant = "dark", type = "mark",
#'                   position = "top-left") |>
#'   grid.draw()
#' }
civilytics_logo <- function(plot,
                            type = c("wordmark", "mark"),
                            variant = c("light", "dark"),
                            position = c("bottom-right", "bottom-left",
                                         "top-right", "top-left"),
                            margin_param = NULL,
                            font_scale = 1.1) {
  position <- match.arg(position)
  logo <- make_logo_grob(type = type, variant = variant, position = position)
  add_logo(plot, logo, margin_param = margin_param, font_scale = font_scale,
           position = position)
}