dev/Multiplot.R

In hutchr/LLSR: Data Analysis of Liquid-Liquid Systems using R

if(getRversion() >= "3.5")
  utils::globalVariables(
    c(
      "grid.newpage",
      "grid.layout",
      "pushViewport",
      "viewport"
    )
  )
# 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.
#
#' @import grid
#
multiplot <-
  function(...,
           plotlist = NULL,
           file,
           cols = 1,
           layout = NULL) {

    
    # 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
              ))
      }
    }
  }