R/geom_miropeats.R

In daewoooo/SVbyEye: Visualization of genomic structural variants

#' A 'ggplot2' geom to draw genomic alignments in a miropeats style.
#'
#' `geom_miropeats()` draws miropeat style polygons between query to target genomic alignments.
#'
#' This geom draws polygons between query to target alignments defined in PAF format.
#' Such alignments are first loaded using \code{\link{readPaf}} function into a \code{tibble} object.
#' Then loaded alignments are converted into the plotting coordinates using \code{\link{paf2coords}} function.
#' molecule. Resulting \code{data.frame} object contains required aesthetics `x` and `y` coordinates as well as
#' `group` field that is required in order to determine which coordinates represent a single alignment.
#'
#' @section Aesthetics:
#' `geom_miropeats()` require or can take the following aesthetics
#' (required aesthetics are in bold):
#'
#' - **x**
#' - **y**
#' - **group**
#' - color
#' - linewidth
#' - linetype
#' - alpha
#' - fill
#' - size
#'
#' @inheritParams ggplot2::geom_polygon
#' @inheritParams ggplot2::stat_identity
#'
#' @param mapping,data,stat,position,na.rm,show.legend,inherit.aes,... As is standard for ggplot2.
#' @param n The number of points to create for each alignment polygon (Default : `100`).
#' @param strength The proportion to move the control point along the y-axis
#' towards the other end of the alignment polygon (Default : `0.5`).
#'
#' @seealso [readPaf()], [paf2coords()]
#' @author David Porubsky
#'
#' @name geom_miropeats
#' @rdname geom_miropeats
#'
#' @examples
#' ## Get PAF to plot
#' paf.file <- system.file("extdata", "test1.paf", package = "SVbyEye")
#' ## Read in PAF
#' paf.table <- readPaf(paf.file = paf.file, include.paf.tags = TRUE, restrict.paf.tags = "cg")
#' ## Convert PAF alignments to plotting coordinates
#' coords <- paf2coords(paf.table = paf.table)
#' ## Make a plot
#' ggplot2::ggplot(coords) +
#'     geom_miropeats(ggplot2::aes(x, y, group = group, fill = direction), alpha = 0.5)
#'
NULL

#' A ggproto class definition to extend the functionality of ggplot2.
#' @importFrom ggforce StatBezier
#' @format NULL
#' @usage NULL
#' @export
StatMiropeats <- ggplot2::ggproto("StatMiropeats", ggplot2::Stat,
    setup_data = function(data, params) {
        if (any(table(data$group) != 4)) {
            stop("Each group must consist of 4 points")
        }
        data
    },
    compute_panel = function(data, scales, strength = 0.5, n = 100) {
        data <- data[order(data$group, data$y), ]
        coords1 <- data[c(TRUE, FALSE, TRUE, FALSE), ]
        coords2 <- data[c(FALSE, TRUE, FALSE, TRUE), ]
        coords1 <- add.control.points(coords1, strength)
        coords1 <- ggforce::StatBezier$compute_panel(coords1, scales, n)
        coords2 <- add.control.points(coords2[rev(seq_len(nrow(coords2))), ], strength)
        coords2 <- ggforce::StatBezier$compute_panel(coords2, scales, n)
        diagonals <- rbind(coords1, coords2)

        # data <- data[order(data$group, data$x, data$y), ]
        # lower <- data[c(TRUE, FALSE, TRUE, FALSE), ]
        # upper <- data[c(FALSE, TRUE, FALSE, TRUE), ]
        # lower <- add_controls(lower, strength)
        # upper <- add_controls(upper[rev(seq_len(nrow(upper))), ], strength)
        # lower <- StatBezier$compute_panel(lower, scales, n)
        # upper <- StatBezier$compute_panel(upper, scales, n)
        # diagonals <- rbind(lower, upper)
        # diagonals$index <- NULL
        # diagonals[order(diagonals$group), ]
    },
    required_aes = c("x", "y", "group"),
    extra_params = c("na.rm", "n", "strength")
)

#' @rdname geom_miropeats
#' @export
geom_miropeats <- function(mapping = NULL, data = NULL, geom = "polygon",
                           stat = "miropeats", position = "identity",
                           n = 100, na.rm = FALSE, strength = 0.5,
                           show.legend = NA, inherit.aes = TRUE, ...) {
    ggplot2::layer(
        data = data, mapping = mapping, stat = stat, geom = geom,
        position = position, show.legend = show.legend, inherit.aes = inherit.aes,
        params = list(na.rm = na.rm, n = n, strength = strength, ...)
    )
}