Connected Barplot in R for Series Data Visualization

connectedBarplot.R

#' Plots a series of barplots and connects them 
#' Modified from https://stackoverflow.com/questions/22560850/barplot-with-connected-series
#' 
#' @param dat NxM matrix with N rows as features and M columns as samples
#' @param color Vector of N colors
#' @param space Space between barplots
#' @param alpha Alpha for area connecting barplots
#' 
#' @examples
#' dat <- matrix(rnorm(100),10,10)
#' dat <- abs(matrix(rnorm(100),10,10)) 
#' connectedBarplot(dat, color=rainbow(nrow(dat)))
#'
connectedBarplot <- function(dat, color=rainbow(nrow(dat)), space=1, alpha=0.5, ...) {  
    b <- barplot(dat, col=color, space = space, ...)                     

    for (i in seq_len(ncol(dat) - 1)) {     
        lines(c(b[i]+0.5, b[i+1]-0.5), c(0, 0)) ## bottom line       
                  
        for (j in seq_len(nrow(dat))) {     
            if (j == 1) {                   
                lines(c(b[i]+0.5, b[i+1]-0.5), c(dat[j,i], dat[j,i+1]))                       
                polygon(c(b[i]+0.5, b[i]+0.5, b[i+1]-0.5, b[i+1]-0.5),                        
                        c(0, dat[j,i], dat[j,i+1], 0),               
                        col=adjustcolor(color[j], alpha.f=alpha))    
            }      
            if (j == 2) {                   
                lines(c(b[i]+0.5, b[i+1]-0.5), c(colSums(dat[1:j,])[i], colSums(dat[1:j,])[i+1]))                      
                polygon(c(b[i]+0.5, b[i]+0.5, b[i+1]-0.5, b[i+1]-0.5),                        
                        c(dat[1,i], colSums(dat[1:j,])[i], colSums(dat[1:j,])[i+1], dat[1,i+1]),                       
                        col=adjustcolor(color[j], alpha.f=alpha))    
            }      
            if (j > 2) {                    
                lines(c(b[i]+0.5, b[i+1]-0.5), c(colSums(dat[1:j,])[i], colSums(dat[1:j,])[i+1]))                      
                polygon(c(b[i]+0.5, b[i]+0.5, b[i+1]-0.5, b[i+1]-0.5),                        
                        c(colSums(dat[1:(j-1),])[i], colSums(dat[1:j,])[i], colSums(dat[1:j,])[i+1], colSums(dat[1:(j-1),])[i+1]),              
                        col=adjustcolor(color[j], alpha.f=alpha))    
            }      
        }          
    }              
}