genomewalker
4/26/2017 - 7:52 PM

## From http://sahir.moosvi.com/2017-01-22-data_does_not_lie/

``````# somewhat hackish solution to:
# based mostly on copy/pasting from ggplot2 geom_violin source:
# altered minorly to allow directionality of density plot
#

library(ggplot2)
library(dplyr)

"%||%" <- function(a, b) {
if (!is.null(a)) a else b
}

#' @rdname ggplot2-ggproto
#' @format NULL
#' @usage NULL
#' @export
GeomFlatViolin <-
ggproto("GeomFlatViolin", Geom,

setup_data = function(data, params) {
data\$width <- data\$width %||%
params\$width %||% (resolution(data\$x, FALSE) * 0.9)

## (3) Here we take the value the user givss and determines which direction the user wants.
if (params\$direction == 1) {
direction <-  +1
} else if (params\$direction == 2) {
direction <-  -1
}

# ymin, ymax, xmin, and xmax define the bounding rectangle for each group
data %>%
group_by(group) %>%
mutate(ymin = min(y),
ymax = max(y),
xmin = x,
## (4) Now we can multiply by the direction to change it.
xmax = x + (direction * width / 2))
},

draw_group = function(data, panel_scales, coord) {
# Find the points for the line to go all the way around
data <- transform(data, xminv = x,
xmaxv = x + violinwidth * (xmax - x))

# Make sure it's sorted properly to draw the outline
newdata <- rbind(plyr::arrange(transform(data, x = xminv), y),
plyr::arrange(transform(data, x = xmaxv), -y))

# Close the polygon: set first and last point the same
# Needed for coord_polar and such
newdata <- rbind(newdata, newdata[1,])

ggplot2:::ggname("geom_flat_violin", GeomPolygon\$draw_panel(newdata, panel_scales, coord))

},

draw_key = draw_key_polygon,

# (5) We also specify the default setting of the direction here
default_aes = aes(weight = 1, colour = "white", fill = "white", size = 0.5,
alpha = 0.5, linetype = "solid", direction = 1),

required_aes = c("x", "y")
)

geom_flat_violin <- function(mapping = NULL, data = NULL, stat = "ydensity",
position = "dodge", trim = TRUE, scale = "area",
show.legend = NA, inherit.aes = TRUE, direction = 1, ...) {

## (1) Right above here is where I added 'direction = 1'
ggplot2::layer(
data = data,
mapping = mapping,
stat = stat,
## This calls the ggproto object
geom = GeomFlatViolin,
position = position,
show.legend = show.legend,
inherit.aes = inherit.aes,
params = list(
trim = trim,
scale = scale,
direction = direction, ## (2), told the layer function that this is a parameter
...
)
)
}``````