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#' Components of a scale:
#'
#' Guide related:
#' * name
#' * breaks
#' * labels
#' * expand
#'
#' Mapping related:
#' * aesthetic
#' * limits
#' * palette
#' * trans
#'
#' Scales are an S3 class with a single mutable component implemented with
#' a reference class - the range of the data. This mutability makes working
#' with scales much easier, because it makes it possible to distribute the
#' training, without having to worry about collecting all the pieces back
#' together again.
#'
#' @name ggscale
#' @S3method print scale
NULL
#' Continuous scale constructor.
#'
#' @export
#' @inheritParams discrete_scale
#' @param minor_breaks Used with date or datetime scales. Either \code{NULL} for
#' no minor breaks, \code{waiver()} for the default breaks (one minor break
#' between each major break), a numeric vector of positions, or a function
#' that given the limits returns a vector of minor breaks.
#' @param limits A numeric vector of length two describing the scale limits.
#' @param rescaler Used by diverging and n colour gradients
#' (i.e. \code{\link{scale_colour_gradient2}}, \code{\link{scale_colour_gradientn}}).
#' @param oob What to do with values outside scale limits (out of bounds)?
#' @keywords internal
continuous_scale <- function(aesthetics, scale_name, palette, name = NULL, breaks = waiver(), minor_breaks = waiver(), labels = waiver(), legend = NULL, limits = NULL, rescaler = rescale, oob = censor, expand = waiver(), na.value = NA_real_, trans = "identity", guide="legend") {
if (!is.null(legend)) {
gg_dep("0.8.9", "\"legend\" argument in scale_XXX is deprecated. Use guide=\"none\" for suppress the guide display.")
if (legend == FALSE) guide = "none"
else if (legend == TRUE) guide = "legend"
}
bad_labels <- is.vector(breaks) && is.vector(labels) &&
length(breaks) != length(labels)
if (bad_labels) {
stop("Breaks and labels have unequal lengths", call. = FALSE)
}
if (is.null(breaks) && !is_position_aes(aesthetics) && guide != "none") {
guide <- "none"
}
trans <- as.trans(trans)
if (!is.null(limits)) {
limits <- trans$trans(limits)
}
structure(list(
call = match.call(),
aesthetics = aesthetics,
scale_name = scale_name,
palette = palette,
range = ContinuousRange$new(),
limits = limits,
trans = trans,
na.value = na.value,
expand = expand,
rescaler = rescaler, # Used by diverging and n colour gradients
oob = oob,
name = name,
breaks = breaks,
minor_breaks = minor_breaks,
labels = labels,
legend = legend,
guide = guide
), class = c(scale_name, "continuous", "scale"))
}
#' Discrete scale constructor.
#'
#' @export
#' @param aesthetics the names of the aesthetics that this scale works with
#' @param scale_name the name of the scale
#' @param palette a palette function that when called with a single integer
#' argument (the number of levels in the scale) returns the values that
#' they should take
#' @param name the name of the scale - used as the axis label or the legend
#' title
#' @param drop drop unused factor levels from the scale (\code{TRUE} or
#' \code{FALSE})
#' @param breaks control the breaks in the guide. There are four possible
#' types of input:
#' \itemize{
#' \item \code{NULL}: don't display any breaks
#' \item a character vector giving the breaks as they should appear on the
#' axis or in the legend.
#' \item \code{waiver()} to use the default break computation.
#' \item a function, that when called with a single argument, a character
#' vector giving the limits of the scale, returns a character vector
#' specifying which breaks to display.
#' }
#' This parameter does not affect in any way how the data is scaled - it
#' only affects the appearance of the legend.
#' @param limits A character vector specifying the data range for the scale.
# The limits control what levels are displayed in the plot, their order,
#' and the default order of their display in guides.
#' @param labels \code{NULL} for no labels, \code{waiver()} for default
#' labels (labels the same as breaks), a character vector the same length
#' as breaks, or a named character vector whose names are used to match
#' replacement the labels for matching breaks.
#' @param legend deprecated. Use \code{guide} instead.
#' @param expand a numeric vector of length two, giving a multiplicative and
#' additive constant used to expand the range of the scales so that there
#' is a small gap between the data and the axes.
#' @param na.value how should missing values be displayed?
#' @param guide the name of, or actual function, used to create the
#' guide.
discrete_scale <- function(aesthetics, scale_name, palette, name = NULL, breaks = waiver(), labels = waiver(), legend = NULL, limits = NULL, expand = waiver(), na.value = NA, drop = TRUE, guide="legend") {
if (!is.null(legend)) {
gg_dep("0.8.9", "\"legend\" argument in scale_XXX is deprecated. Use guide=\"none\" for suppress the guide display.")
if (legend == FALSE) guide = "none"
else if (legend == TRUE) guide = "legend"
}
bad_labels <- is.vector(breaks) && is.vector(labels) &&
length(breaks) != length(labels)
if (bad_labels) {
stop("Breaks and labels have unequal lengths", call. = FALSE)
}
if (is.null(breaks) && !is_position_aes(aesthetics) && guide != "none") {
guide <- "none"
}
structure(list(
call = match.call(),
aesthetics = aesthetics,
scale_name = scale_name,
palette = palette,
range = DiscreteRange$new(),
limits = limits,
na.value = na.value,
expand = expand,
name = name,
breaks = breaks,
labels = labels,
legend = legend,
drop = drop,
guide = guide
), class = c(scale_name, "discrete", "scale"))
}
# Train scale from a data frame.
#
# @return updated range (invisibly)
# @seealso \code{\link{scale_train}} for scale specific generic method
scale_train_df <- function(scale, df) {
if (empty(df)) return()
aesthetics <- intersect(scale$aesthetics, names(df))
for(aesthetic in aesthetics) {
scale_train(scale, df[[aesthetic]])
}
invisible()
}
# Train an individual scale from a vector of data.
#
scale_train <- function(scale, x) {
if (length(x) == 0) return()
UseMethod("scale_train")
}
#' @S3method scale_train continuous
scale_train.continuous <- function(scale, x) {
scale$range$train(x)
}
#' @S3method scale_train discrete
scale_train.discrete <- function(scale, x) {
scale$range$train(x, drop = scale$drop)
}
# Reset scale, untraining ranges
scale_reset <- function(scale, x) UseMethod("scale_reset")
#' @S3method scale_reset default
scale_reset.default <- function(scale, x) {
scale$range$reset()
}
scale_is_empty <- function(scale) UseMethod("scale_is_empty")
#' @S3method scale_is_empty default
scale_is_empty.default <- function(scale) {
is.null(scale$range$range) && is.null(scale$limits)
}
# @return list of transformed variables
scale_transform_df <- function(scale, df) {
if (empty(df)) return()
aesthetics <- intersect(scale$aesthetics, names(df))
if (length(aesthetics) == 0) return()
lapply(df[aesthetics], scale_transform, scale = scale)
}
scale_transform <- function(scale, x) UseMethod("scale_transform")
#' @S3method scale_transform continuous
scale_transform.continuous <- function(scale, x) {
scale$trans$trans(x)
}
#' @S3method scale_transform discrete
scale_transform.discrete <- function(scale, x) {
x
}
# @return list of mapped variables
scale_map_df <- function(scale, df, i = NULL) {
if (empty(df)) return()
aesthetics <- intersect(scale$aesthetics, names(df))
names(aesthetics) <- aesthetics
if (length(aesthetics) == 0) return()
if (is.null(i)) {
lapply(aesthetics, function(j) scale_map(scale, df[[j]]))
} else {
lapply(aesthetics, function(j) scale_map(scale, df[[j]][i]))
}
}
# @kohske
# scale_map tentatively accept limits argument.
# scale_map replaces oob (i.e., outside limits) values with NA.
#
# Previously limits are always scale_limits(scale).
# But if this function is called to get breaks,
# and breaks spans oob, the oob breaks is replaces by NA.
# This makes impossible to display oob breaks.
# Now coord_train calls this function with limits determined by coord (with expansion).
scale_map <- function(scale, x, limits) UseMethod("scale_map")
#' @S3method scale_map continuous
scale_map.continuous <- function(scale, x, limits = scale_limits(scale)) {
x <- scale$oob(scale$rescaler(x, from = limits))
# Points are rounded to the nearest 500th, to reduce the amount of
# work that the scale palette must do - this is particularly important
# for colour scales which are rather slow. This shouldn't have any
# perceptual impacts.
x <- round_any(x, 1 / 500)
uniq <- unique(x)
pal <- scale$palette(uniq)
scaled <- pal[match(x, uniq)]
ifelse(!is.na(scaled), scaled, scale$na.value)
}
#' @S3method scale_map discrete
scale_map.discrete <- function(scale, x, limits = scale_limits(scale)) {
n <- sum(!is.na(limits))
pal <- scale$palette(n)
if (is.null(names(pal))) {
pal_match <- pal[match(as.character(x), limits)]
} else {
pal_match <- pal[match(as.character(x), names(pal))]
pal_match <- unname(pal_match)
}
ifelse(is.na(x) | is.na(pal_match), scale$na.value, pal_match)
}
scale_limits <- function(scale) {
if (scale_is_empty(scale)) return(c(0, 1))
UseMethod("scale_limits")
}
#' @S3method scale_limits default
scale_limits.default <- function(scale) {
scale$limits %||% scale$range$range
}
# @kohske
# this (internal) function always returns a vector of length 2 of giving
# multiplicative and additive expansion constants.
# if scale' expand is specified, return it.
# if is.waive, return c(0, 0)
scale_expand <- function(scale) UseMethod("scale_expand")
#' @S3method scale_expand default
scale_expand.default <- function(scale) {
if (is.waive(scale$expand)) c(0, 0)
else scale$expand
}
# The phyical size of the scale, if a position scale
# Unlike limits, this always returns a numeric vector of length 2
# @kohske
# scale_dimension uses scale_expand(scale) for expansion by default.
scale_dimension <- function(scale, expand = scale_expand(scale)) UseMethod("scale_dimension")
#' @S3method scale_dimension continuous
scale_dimension.continuous <- function(scale, expand = scale_expand(scale)) {
expand_range(scale_limits(scale), expand[1], expand[2])
}
#' @S3method scale_dimension discrete
scale_dimension.discrete <- function(scale, expand = scale_expand(scale)) {
expand_range(length(scale_limits(scale)), expand[1], expand[2])
}
scale_breaks <- function(scale, limits = scale_limits(scale)) {
if (scale_is_empty(scale)) return(numeric())
UseMethod("scale_breaks")
}
#' @S3method scale_breaks continuous
scale_breaks.continuous <- function(scale, limits = scale_limits(scale)) {
# Limits in transformed space need to be converted back to data space
limits <- scale$trans$inv(limits)
if (is.null(scale$breaks)) {
return(NULL)
} else if (length(scale$breaks) == 1 && !is.function(scale$breaks) && is.na(scale$breaks)) {
gg_dep("0.8.9", "breaks = NA is deprecated. Please use breaks = NULL to remove breaks in the scale.")
return(NULL)
} else if (zero_range(as.numeric(limits))) {
breaks <- limits[1]
} else if (is.waive(scale$breaks)) {
breaks <- scale$trans$breaks(limits)
} else if (is.function(scale$breaks)) {
breaks <- scale$breaks(limits)
} else {
breaks <- scale$breaks
}
# Breaks in data space need to be converted back to transformed space
# And any breaks outside the dimensions need to be flagged as missing
#
# @kohske
# TODO: replace NA with something else for flag.
# guides cannot discriminate oob from missing value.
breaks <- censor(scale$trans$trans(breaks), scale$trans$trans(limits))
if (length(breaks) == 0) {
stop("Zero breaks in scale for ", paste(scale$aesthetics, collapse = "/"),
call. = FALSE)
}
breaks
}
#' @S3method scale_breaks discrete
scale_breaks.discrete <- function(scale, limits = scale_limits(scale)) {
if (is.null(scale$breaks)) {
return(NULL)
} else if (length(scale$breaks) == 1 && !is.function(scale$breaks) && is.na(scale$breaks)) {
gg_dep("0.8.9", "breaks = NA is deprecated. Please use breaks = NULL to remove breaks in the scale.")
return(NULL)
} else if (is.waive(scale$breaks)) {
breaks <- limits
} else if (is.function(scale$breaks)) {
breaks <- scale$breaks(limits)
} else {
breaks <- scale$breaks
}
# Breaks can only occur only on values in domain
in_domain <- intersect(breaks, scale_limits(scale))
structure(in_domain, pos = match(in_domain, breaks))
}
# The numeric position of scale breaks, used by coord/guide
scale_break_positions <- function(scale, range = scale_limits(scale)) {
scale_map(scale, scale_breaks(scale, range))
}
scale_breaks_minor<- function(scale, n = 2, b = scale_break_positions(scale), limits = scale_limits(scale)) {
UseMethod("scale_breaks_minor")
}
#' @S3method scale_breaks_minor continuous
scale_breaks_minor.continuous <- function(scale, n = 2, b = scale_break_positions(scale), limits = scale_limits(scale)) {
if (zero_range(as.numeric(limits))) {
return()
}
if (is.null(scale$minor_breaks)) {
return(NULL)
} else if (length(scale$minor_breaks) == 1 && !is.function(scale$minor_breaks) && is.na(scale$minor_breaks)) {
gg_dep("0.8.9", "minor_breaks = NA is deprecated. Please use minor_breaks = NULL to remove minor breaks in the scale.")
return(NULL)
} else if (is.waive(scale$minor_breaks)) {
if (is.null(b)) {
breaks <- NULL
} else {
b <- b[!is.na(b)]
if (length(b) < 2) return()
bd <- diff(b)[1]
if (min(limits) < min(b)) b <- c(b[1] - bd, b)
if (max(limits) > max(b)) b <- c(b, b[length(b)] + bd)
breaks <- unique(unlist(mapply(seq, b[-length(b)], b[-1], length=n+1,
SIMPLIFY = FALSE)))
}
} else if (is.function(scale$minor_breaks)) {
# Find breaks in data space, and convert to numeric
breaks <- scale$minor_breaks(scale$trans$inv(limits))
breaks <- scale$trans$trans(breaks)
} else {
breaks <- scale$minor_breaks
}
# Any minor breaks outside the dimensions need to be thrown away
discard(breaks, limits)
}
#' @S3method scale_breaks_minor discrete
scale_breaks_minor.discrete <- function(...) NULL
scale_breaks_minor_positions <- function(scale) {
scale_map(scale, scale_breaks_minor(scale))
}
scale_labels <- function(scale, breaks = scale_breaks(scale)) {
if (scale_is_empty(scale)) return(character())
UseMethod("scale_labels")
}
#' @S3method scale_labels continuous
scale_labels.continuous <- function(scale, breaks = scale_breaks(scale)) {
if (is.null(breaks)) return(NULL)
breaks <- scale$trans$inv(breaks)
if (is.null(scale$labels)) {
return(NULL)
} else if (length(scale$labels) == 1 && !is.function(scale$labels) && is.na(scale$labels)) {
gg_dep("0.8.9", "labels = NA is deprecated. Please use labels = NULL to remove labels in the scale.")
return(NULL)
} else if (is.waive(scale$labels)) {
labels <- scale$trans$format(breaks)
} else if (is.function(scale$labels)) {
labels <- scale$labels(breaks)
} else {
labels <- scale$labels
}
if (length(labels) != length(breaks)) {
stop("Breaks and labels are different lengths")
}
labels
}
#' @S3method scale_labels discrete
scale_labels.discrete <- function(scale, breaks = scale_breaks(scale)) {
if (is.null(breaks)) return(NULL)
if (is.null(scale$labels)) {
return(NULL)
} else if (length(scale$labels) == 1 && !is.function(scale$labels) && is.na(scale$labels)) {
gg_dep("0.8.9", "labels = NA is deprecated. Please use labels = NULL to remove labels in the scale.")
return(NULL)
}else if (is.waive(scale$labels)) {
format(scale_breaks(scale), justify = "none", trim = TRUE)
} else if (is.function(scale$labels)) {
scale$labels(breaks)
} else {
if (!is.null(names(scale$labels))) {
# If labels have names, use them to match with breaks
labels <- breaks
map <- match(names(scale$labels), labels, nomatch = 0)
labels[map] <- scale$labels[map != 0]
labels
} else {
labels <- scale$labels
# Need to ensure that if breaks were dropped, corresponding labels are too
pos <- attr(breaks, "pos")
if (!is.null(pos)) {
labels <- labels[pos]
}
labels
}
}
}
named_labels <- function(breaks, labels) {
breaks[match(names(labels), breaks, nomatch = 0)] <- labels
breaks
}
print.scale <- function(x, ...) {
print(x$call)
}
scale_clone <- function(scale) UseMethod("scale_clone")
#' @S3method scale_clone continuous
scale_clone.continuous <- function(scale) {
new <- scale
new$range <- ContinuousRange$new()
new
}
#' @S3method scale_clone discrete
scale_clone.discrete <- function(scale) {
new <- scale
new$range <- DiscreteRange$new()
new
}
scale_break_info <- function(scale, range = NULL) UseMethod("scale_break_info")
#' @S3method scale_break_info discrete
scale_break_info.discrete <- function(scale, range = NULL) {
# for discrete, limits != range
limits <- scale_limits(scale)
major <- scale_breaks(scale, limits)
if (is.null(major)) {
labels <- major_n <- NULL
} else {
labels <- scale_labels(scale, major)
labels <- labels[!is.na(labels)]
major <- scale_map(scale, major)
major <- major[!is.na(major)]
# rescale breaks [0, 1], which are used by coord/guide
major_n <- rescale(major, from = range)
}
list(range = range, labels = labels,
major = major_n, minor = NULL,
major_source = major, minor_source = NULL)
}
#' @S3method scale_break_info continuous
scale_break_info.continuous <- function(scale, range = NULL) {
# range
if (is.null(range)) range <- scale_dimension(scale)
# major breaks
major <- scale_breaks(scale, range)
# labels
labels <- scale_labels(scale, major)
# drop oob breaks/labels by testing major == NA
if (!is.null(labels)) labels <- labels[!is.na(major)]
if (!is.null(major)) major <- major[!is.na(major)]
# minor breaks
minor <- scale_breaks_minor(scale, b = major, limits = range)
if (!is.null(minor)) minor <- minor[!is.na(minor)]
# rescale breaks [0, 1], which are used by coord/guide
major_n <- rescale(major, from = range)
minor_n <- rescale(minor, from = range)
list(range = range, labels = labels,
major = major_n, minor = minor_n,
major_source = major, minor_source = minor)
}
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