R/multiplot.R

Defines functions multiplot

Documented in multiplot

#' Multiple plot function
#'
#' @param plotlist
#' list of ggplot objects.
#'
#' @param ...
#' ggplot objects
#'
#' @param cols
#' Number of columns in layout
#'
#' @param layout
#' A matrix specifying the layout. If present, 'cols' is ignored.
#'
#' @description
#' If the layout is something like matrix(c(1,2,3,3), nrow=2, byrow=TRUE),
#' then plot 1 will go in the upper left, 2 will go in the upper right, and
#' 3 will go all the way across the bottom.
#'
#' @source http://www.cookbook-r.com/Graphs/Multiple_graphs_on_one_page_(ggplot2)/
#'
#' @export
#'
#'
multiplot <- function(..., plotlist = NULL, cols = 1, layout = NULL) {
    library(grid)

    # Make a list from the ... arguments and plotlist
    plots <- c(list(...), plotlist)

    numPlots = length(plots)

    # If layout is NULL, then use 'cols' to determine layout
    if (is.null(layout)) {
        # Make the panel
        # ncol: Number of columns of plots
        # nrow: Number of rows needed, calculated from # of cols
        layout <- matrix(seq(1, cols * ceiling(numPlots/cols)),
                         ncol = cols, nrow = ceiling(numPlots/cols))
    }

    if (numPlots==1) {
        print(plots[[1]])

    } else {
        # Set up the page
        grid.newpage()
        pushViewport(viewport(layout = grid.layout(nrow(layout), ncol(layout))))

        # Make each plot, in the correct location
        for (i in 1:numPlots) {
            # Get the i,j matrix positions of the regions that contain this subplot
            matchidx <- as.data.frame(which(layout == i, arr.ind = TRUE))

            print(plots[[i]], vp = viewport(layout.pos.row = matchidx$row,
                                            layout.pos.col = matchidx$col))
        }
    }
}
mottensmann/MyR documentation built on May 20, 2019, 8:02 p.m.