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civilyticsR/R/logo.R
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jared 41fe2b6170
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fix: use full-bleed background rect instead of opaque logo grob
The previous fix applied the plot's background to the logo grob
directly, which made it opaque and covered caption/axis text that
overlaps into the logo area via negative margins.

Instead, wrap the entire arrangeGrob composition in a grobTree with
a background rectGrob behind it. This fills transparent areas (logo
strip, padding gaps) with the plot's background color while keeping
the logo grob itself transparent so overlapping text remains visible.
2026-05-19 22:12:03 -06:00

364 lines
13 KiB
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)
# Capture the plot's background color so we can fill the entire composed
# grob with it. The logo grob must stay transparent (theme_void) so that
# caption/axis text overlapping via negative margins remains visible.
bg_fill <- plot$theme$plot.background$fill
# Inflate text sizes to compensate for arrangeGrob viewport shrinkage.
# All theme text elements use rel() sizing, so scaling the root 'text'
# element cascades to titles, axis labels, legends, captions, and strips.
if (!is.null(font_scale) && font_scale != 1) {
base_size <- plot$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"))
}
composed <- 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"))
}
composed <- arrangeGrob(plot, logo, heights = c(0.93, 0.1),
padding = unit(0.1, "line"))
}
# Wrap with a full-bleed background rect so any transparent areas (the
# logo strip, padding gaps) pick up the plot's background color instead
# of the device default (white).
if (!is.null(bg_fill) && !is.na(bg_fill)) {
bg_rect <- grid::rectGrob(gp = grid::gpar(fill = bg_fill, col = NA))
grid::grobTree(bg_rect, composed)
} else {
composed
}
}
#' 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$labels) == "caption")
}
#' Add a logo to multiple ggplot2 objects
#'
#' @param plot_list a list containing ggplot2 objects
#' @param logo a grob containing the logo created with `make_logo_grob`
#' @param nrow an integer, default = 1, for the number of rows to align the plots in
#' @param widths an optional vector the same length as plot_list with the widths for each plot
#' @param margin_param a number giving the adjustment up or down to help manually align logo and captions
#' @param font_scale Numeric. Multiplicative scaling factor applied to text
#' sizes before composing. Default `1.1`. See [add_logo()] for details.
#'
#' @return a grid object
#' @note The resulting object needs to be drawn to the screen using grid.draw()
#' @importFrom gridExtra arrangeGrob
#' @importFrom ggplot2 theme
#' @importFrom grid grid.draw
#' @export
#'
#' @examples
#' \dontrun{
#' library(ggplot2); library(grid)
#' tmp_plot <- ggplot(mtcars) + aes(x = hp, y = disp) + geom_point() + theme_civilytics()
#' tmp_logo <- make_logo_grob()
#' plot_and_logo <- add_logo(tmp_plot, tmp_logo)
#' grid.draw(plot_and_logo)
#' dev.off()
#' }
add_logo_ga <- function(plot_list, logo, nrow = 1, widths = NULL,
margin_param = NULL, font_scale = 1.1) {
# Capture the background color from the first plot
bg_fill <- plot_list[[1]]$theme$plot.background$fill
# 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)
}
composed <- arrangeGrob(hold, logo, heights = c(0.93, .07))
if (!is.null(bg_fill) && !is.na(bg_fill)) {
bg_rect <- grid::rectGrob(gp = grid::gpar(fill = bg_fill, col = NA))
grid::grobTree(bg_rect, composed)
} else {
composed
}
}
#' 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)
}