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# Create a new layer
# Layer objects store the layer of an object.
#
# They have the following attributes:
#
# * data
# * geom + parameters
# * statistic + parameters
# * position + parameters
# * aesthetic mapping
# * flag for display guide: TRUE/FALSE/NA. in the case of NA, decision depends on a guide itself.
#
# Can think about grob creation as a series of data frame transformations.
Layer <- proto(expr = {
geom <- NULL
geom_params <- NULL
stat <- NULL
stat_params <- NULL
data <- NULL
mapping <- NULL
position <- NULL
params <- NULL
inherit.aes <- FALSE
new <- function (., geom=NULL, geom_params=NULL, stat=NULL, stat_params=NULL, data=NULL, mapping=NULL, position=NULL, params=NULL, ..., inherit.aes = TRUE, legend = NA, subset = NULL, show_guide = NA) {
# now, as for the guide, we can choose only if the layer is included or not in the guide: guide = TRUE or guide = FALSE
# in future, it may be better if we can choose which aes of this layer is included in the guide, e.g.: guide = c(colour = TRUE, size = FALSE)
if (!is.na(legend)) {
warning("\"legend\" argument in geom_XXX and stat_XXX is deprecated. Use show_guide = TRUE or show_guide = FALSE for display or suppress the guide display.")
show_guide = legend
}
if (!is.na(show_guide) && !is.logical(show_guide)) {
warning("`show_guide` in geom_XXX and stat_XXX must be logical.")
show_guide = FALSE
}
if (is.null(geom) && is.null(stat)) stop("Need at least one of stat and geom")
data <- fortify(data)
if (!is.null(mapping) && !inherits(mapping, "uneval")) stop("Mapping should be a list of unevaluated mappings created by aes or aes_string")
if (is.character(geom)) geom <- Geom$find(geom)
if (is.character(stat)) stat <- Stat$find(stat)
if (is.character(position)) position <- Position$find(position)$new()
if (is.null(geom)) geom <- stat$default_geom()
if (is.null(stat)) stat <- geom$default_stat()
if (is.null(position)) position <- geom$default_pos()$new()
match.params <- function(possible, params) {
if ("..." %in% names(possible)) {
params
} else {
params[match(names(possible), names(params), nomatch=0)]
}
}
if (is.null(geom_params) && is.null(stat_params)) {
params <- c(params, list(...))
params <- rename_aes(params) # Rename American to British spellings etc
geom_params <- match.params(geom$parameters(), params)
stat_params <- match.params(stat$parameters(), params)
stat_params <- stat_params[setdiff(names(stat_params),
names(geom_params))]
} else {
geom_params <- rename_aes(geom_params)
}
proto(.,
geom=geom, geom_params=geom_params,
stat=stat, stat_params=stat_params,
data=data, mapping=mapping, subset=subset,
position=position,
inherit.aes = inherit.aes,
show_guide = show_guide,
)
}
clone <- function(.) {
as.proto(as.list.environment(., all.names=TRUE))
}
use_defaults <- function(., data) {
df <- aesdefaults(data, .$geom$default_aes(), NULL)
# Override mappings with atomic parameters
gp <- intersect(c(names(df), .$geom$required_aes), names(.$geom_params))
gp <- gp[unlist(lapply(.$geom_params[gp], is.atomic))]
# Check that mappings are compatable length: either 1 or the same length
# as the data
param_lengths <- vapply(.$geom_params[gp], length, numeric(1))
bad <- param_lengths != 1L & param_lengths != nrow(df)
if (any(bad)) {
stop("Incompatible lengths for set aesthetics: ",
paste(names(bad), collapse = ", "), call. = FALSE)
}
df[gp] <- .$geom_params[gp]
df
}
layer_mapping <- function(., mapping = NULL) {
# For certain geoms, it is useful to be able to ignore the default
# aesthetics and only use those set in the layer
if (.$inherit.aes) {
aesthetics <- compact(defaults(.$mapping, mapping))
} else {
aesthetics <- .$mapping
}
# Drop aesthetics that are set or calculated
set <- names(aesthetics) %in% names(.$geom_params)
calculated <- is_calculated_aes(aesthetics)
aesthetics[!set & !calculated]
}
pprint <- function(.) {
if (is.null(.$geom)) {
cat("Empty layer\n")
return(invisible());
}
if (!is.null(.$mapping)) {
cat("mapping:", clist(.$mapping), "\n")
}
.$geom$print(newline=FALSE)
cat(clist(.$geom_params), "\n")
.$stat$print(newline=FALSE)
cat(clist(.$stat_params), "\n")
.$position$print()
}
compute_aesthetics <- function(., data, plot) {
aesthetics <- .$layer_mapping(plot$mapping)
if (!is.null(.$subset)) {
include <- data.frame(eval.quoted(.$subset, data, plot$env))
data <- data[rowSums(include, na.rm = TRUE) == ncol(include), ]
}
# Override grouping if set in layer.
if (!is.null(.$geom_params$group)) {
aesthetics["group"] <- .$geom_params$group
}
scales_add_defaults(plot$scales, data, aesthetics, plot$plot_env)
# Evaluate aesthetics in the context of their data frame
evaled <- compact(
eval.quoted(aesthetics, data, plot$plot_env))
lengths <- vapply(evaled, length, integer(1))
n <- if (length(lengths) > 0) max(lengths) else 0
wrong <- lengths != 1 & lengths != n
if (any(wrong)) {
stop("Aesthetics must either be length one, or the same length as the data",
"Problems:", paste(aesthetics[wrong], collapse = ", "), call. = FALSE)
}
if (empty(data) && n > 0) {
# No data, and vectors suppled to aesthetics
evaled$PANEL <- 1
} else {
evaled$PANEL <- data$PANEL
}
data.frame(evaled)
}
calc_statistic <- function(., data, scales) {
if (empty(data)) return(data.frame())
check_required_aesthetics(.$stat$required_aes,
c(names(data), names(.$stat_params)),
paste("stat_", .$stat$objname, sep=""))
res <- NULL
try(res <- do.call(.$stat$calculate_groups, c(
list(data=as.name("data"), scales=as.name("scales")),
.$stat_params)
))
if (is.null(res)) return(data.frame())
res
}
map_statistic <- function(., data, plot) {
if (empty(data)) return(data.frame())
# Assemble aesthetics from layer, plot and stat mappings
aesthetics <- .$mapping
if (.$inherit.aes) {
aesthetics <- defaults(aesthetics, plot$mapping)
}
aesthetics <- defaults(aesthetics, .$stat$default_aes())
aesthetics <- compact(aesthetics)
new <- strip_dots(aesthetics[is_calculated_aes(aesthetics)])
if (length(new) == 0) return(data)
# Add map stat output to aesthetics
stat_data <- as.data.frame(lapply(new, eval, data, baseenv()))
names(stat_data) <- names(new)
# Add any new scales, if needed
scales_add_defaults(plot$scales, data, new, plot$plot_env)
# Transform the values, if the scale say it's ok
# (see stat_spoke for one exception)
if (.$stat$retransform) {
stat_data <- scales_transform_df(plot$scales, stat_data)
}
cunion(stat_data, data)
}
reparameterise <- function(., data) {
if (empty(data)) return(data.frame())
.$geom$reparameterise(data, .$geom_params)
}
adjust_position <- function(., data) {
ddply(data, "PANEL", function(data) {
.$position$adjust(data)
})
}
make_grob <- function(., data, scales, cs) {
if (empty(data)) return(zeroGrob())
data <- .$use_defaults(data)
check_required_aesthetics(.$geom$required_aes,
c(names(data), names(.$geom_params)),
paste("geom_", .$geom$objname, sep=""))
do.call(.$geom$draw_groups, c(
data = list(as.name("data")),
scales = list(as.name("scales")),
coordinates = list(as.name("cs")),
.$geom_params
))
}
class <- function(.) "layer"
})
#' Create a new layer
#'
#' @keywords internal
#' @export
layer <- Layer$new
# Determine if aesthetic is calculated
is_calculated_aes <- function(aesthetics) {
match <- "\\.\\.([a-zA-z._]+)\\.\\."
stats <- rep(FALSE, length(aesthetics))
grepl(match, sapply(aesthetics, deparse))
}
# Strip dots from expressions
strip_dots <- function(aesthetics) {
match <- "\\.\\.([a-zA-z._]+)\\.\\."
strings <- lapply(aesthetics, deparse)
strings <- lapply(strings, gsub, pattern = match, replacement = "\\1")
lapply(strings, function(x) parse(text = x)[[1]])
}
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