R/geom_seed.R

In YuLab-SMU/ggmsa: Plot Multiple Sequence Alignment using 'ggplot2'

##' Highlighting the seed in miRNA sequences
##'
##'
##' @title geom_seed
##' @param seed a character string.Specifying the miRNA seed sequence
##'  like 'GAGGUAG'.
##' @param star a logical value indicating whether asterisks should 
##' be displayed.
##' @return a ggplot layer
##' @author Lang Zhou
##' @examples
##' miRNA_sequences <- system.file("extdata/seedSample.fa", package="ggmsa")
##' ggmsa(miRNA_sequences, font = 'DroidSansMono', 
##'       color = "Chemistry_NT", none_bg = TRUE) +
##' geom_seed(seed = "GAGGUAG", star = FALSE)
##' ggmsa(miRNA_sequences, font = 'DroidSansMono', 
##'       color = "Chemistry_NT") +
##' geom_seed(seed = "GAGGUAG", star = TRUE)
##' @export
geom_seed <- function(seed, star = FALSE) {
    structure(list(seed = seed,
                   star = star),
              class = "seed")
}


geom_seed1 <- function(tidyData, seed, star) {
    get_asteriskScale(tidyData)
    tidyData$y <- as.numeric(tidyData$name)
    seq_first <- tidyData[tidyData$y == 1,]
    char <- seq_first$character
    char <- paste(char, collapse = "")
    seedPos <- regexpr(seed,char)
    #locate <- str_locate(char, seed)
    #df_locate <- as.data.frame(locate)
    #seedPos <- df_locate$start # start position of seed region
    seedLen <- nchar(seed) # length of seed region
    numSeq <- max(tidyData$y) # number of sequences
    shadingLen <- getOption("shadingLen") #shading width
    shading_alpha <- getOption("shading_alpha")

    x <- seedPos - .5 #the x coordinate of the lower left corner
    y <- 1 - .5 - shadingLen #the y coordinate of the lower left corner
    yy <- numSeq + .5 + shadingLen # #the y coordinate of the top right corner
    xx <- x + seedLen #the x coordinate of the top right corner

    shadingData <- data.frame(x = c(x, x, xx, xx),
                    y = c(y, yy, yy, y),
                    t = c('a', 'a', 'a','a'))
    starData <- data.frame(star_x = seq(seedPos, length.out = nchar(seed)),
                            star_y = rep(y, times = nchar(seed)))

    if(isTRUE(star)) {
        ly_star <- geom_asterisk(data = starData, 
                                 aes_(x = ~star_x, y = ~star_y))
        return(ly_star)
    }

    mapping <- aes_(x= ~x, y= ~y, group= ~t, fill = ~I('#bebebe'))
    ly_seed <- geom_polygon(data = shadingData, 
                            mapping = mapping, 
                            alpha = shading_alpha)
    return(ly_seed)
 }


get_asteriskScale <- function(tidyData) {
    m <- max(tidyData$position)
    seq_name <- factor(tidyData$name, levels = unique(tidyData$name))
    n <- max(as.numeric(seq_name))
    char_scale <- diff(range(star$x))/diff(range(star$y))
    char_scale_2 <- char_scale * 3/2 * n/m

    return(options("char_scale_2" = char_scale_2))

}