R/multiplot.R

Defines functions multiplot

Documented in multiplot

#' @title Complex Plot Arrangements for ggplot Objects
#' 
#' @description Arrange multiple ggplot objects on graphics device 
#' 
#' 
#' @param plotlist a list of ggplot plots to plot
#' @param cols number of columns in layout
#' @param layout a matrix specifying the layout
#' @param ... ggplot objects to be passed to the function
#' 
#' @author Winston Chang <winston@@stdout.org> 
#' 
#' @seealso \code{\link{layout}}
#' @export
#' 
#' @examples
#' p1 <- ggplot(data = HSWRESTLER, aes(x = skfat, y = hwfat)) + geom_point()
#' p2 <- ggplot(data = HSWRESTLER, aes(x = tanfat, y = hwfat)) + geom_point()
#' multiplot(p1, p2, cols = 2)
#' multiplot(p1, p2, cols = 2, layout=matrix(c(1, 0, 0, 2), byrow = TRUE, nrow = 2))
#' 
#' @keywords programming
#####################################################################################
# Multiple plot function
#
# ggplot objects can be passed in ..., or to plotlist (as a list of ggplot objects)
# - cols:   Number of columns in layout
# - layout: A matrix specifying the layout. If present, 'cols' is ignored.
#
# 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.
#
multiplot <- function(..., plotlist=NULL, cols=1, layout=NULL) {
  # require(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))
    }
  }
}
alanarnholt/PASWR2 documentation built on June 2, 2022, 5:20 a.m.