Multiple plot piechart in R

Question

The following code modified from an earlier post produces a plot window containing a pie-chart. I would like to be able to place multiple pie charts in the window, but am having trouble with placement. Successive calls to the pie chart function do not populate the plot in the order I expect (two pie charts are placed in opposite corners of the plot, and then further calls do not add any more pie charts, even though there is space). Is there any way to correct this? I eventually need 6 pie charts (3 rows and 2 columns).

rm(list = ls(all = TRUE))

# DATA
mydf <- structure(list(inner_category = structure(c(3L, 3L, 3L, 3L, 2L, 2L, 
  2L, 1L, 5L, 5L, 4L), .Label = c("group1", "group2", "group3", 
  "group4", "group5"), class = "factor"), outer_category = structure(c(5L, 
  6L, 7L, 8L, 2L, 3L, 4L, 1L, 10L, 11L, 9L), .Label = c("group1_A", 
  "group1_B", "group1_C", "group1_D", "group2_A", "group2_B", 
  "group2_C", "group2_D", "group3_A", "group4_A", "group4_B"), 
  class = "factor"), share = c(10.85, 7.35, 33.06, 2.81, 1.58, 
  13.12, 5.43, 9.91, 1.42, 4.55, 1.65)), .Names = c("inner_category", "outer_category", "share"),
  row.names = c(NA, -11L), class = "data.frame")

mydf$total <- with(mydf1, ave(share, inner_category, FUN = sum))

# PLOTTING WINDOW
quartz("Quartz", width=9, height=8, pointsize=18)
par(mfrow=c(3,2), mar=c(4,4,2,0.5), mgp = c(1.5, 0.3, 0), tck = -0.01)

#FUNCTION
donutplotfunction <- function(myfile, width = 15, height = 11) { 

    ## HOUSEKEEPING
    if (missing(myfile)) file <- getwd()
    op <- par(no.readonly = TRUE); on.exit(par(op))

    nr <- nrow(myfile)
    width <- max(sqrt(myfile$share)) / 0.8

    tbl <- with(myfile, table(inner_category)[order(unique(inner_category))])
    cols <- c('cyan2','red','orange','green','dodgerblue2')
    cols <- unlist(Map(rep, cols, tbl))

    ## LOOP TO CREATE PIE SLICES
    par(omi = c(0.5,0.5,0.75,0.5), mai = c(0.1,0.1,0.1,0.1), las = 1)
    for (i in 1:nr) {
    par(new = TRUE)

    ## CREATE COLORS AND SHADES
    rgb <- col2rgb(cols[i])
    f0 <- rep(NA, nr)
    f0[i] <- rgb(rgb[1], rgb[2], rgb[3], 190 / sequence(tbl)[i], maxColorValue = 255)

    ## CREATE LABELS FOR THE OUTERMOST SECTION
    lab <- with(myfile, sprintf('%s: %s', outer_category, share))
    if (with(myfile, share[i] == max(share))) {
      lab0 <- lab
    } else lab0 <- NA

    ## PLOT THE OUTSIDE PIE AND SHADES OF SUBGROUPS
    par(lwd = 0.1)
    pie(myfile$share, border = "white", radius = 5 / width, col = f0, labels = lab0, cex = 0.7, ticks = 0)

    ## REPEAT ABOVE FOR THE MAIN GROUPS
    par(new = TRUE)
    rgb <- col2rgb(cols[i])
    f0[i] <- rgb(rgb[1], rgb[2], rgb[3], maxColorValue = 255)
    par(lwd = 0.1)
    pie(myfile$share, border = "white", radius = 4 / width, col = f0, labels = NA)
    }

    ## GRAPH TITLE
    text(x = c(-.05, -.05, 0.15, .25, .3), y = c(.08, -.12, -.15, -.08, -.02), labels = unique(myfile$inner_category), col = 'black', cex = 0.8)
    mtext('Figure Main Title', side = 3, line = -1, adj = 0, cex = 1, outer = TRUE)
}

donutplotfunction(mydf)

Answer 1

First, a couple of tips. (1) It is easier for people to help if you post a minimal example. Your code has a lot of details that aren't relevant to the problem--try to eliminate such code. (2) Since rgb is a function name, try to avoid using rgb for a variable name. (3) You don't need to loop over pie slices--just have R draw all slices at once. (4) You had too many par(new=TRUE) statements.

I think the following code is the essence of what you want.

mydf <- structure(list(inner_category = structure(c(3L, 3L, 3L, 3L, 2L, 2L, 
2L, 1L, 5L, 5L, 4L), .Label = c("group1", "group2", "group3", 
"group4", "group5"), class = "factor"), outer_category = structure(c(5L, 
6L, 7L, 8L, 2L, 3L, 4L, 1L, 10L, 11L, 9L), .Label = c("group1_A", 
"group1_B", "group1_C", "group1_D", "group2_A", "group2_B", 
"group2_C", "group2_D", "group3_A", "group4_A", "group4_B"), 
class = "factor"), share = c(10.85, 7.35, 33.06, 2.81, 1.58, 
13.12, 5.43, 9.91, 1.42, 4.55, 1.65)), .Names = c("inner_category", "outer_category", "share"),
row.names = c(NA, -11L), class = "data.frame")

donutplotfunction <- function(myfile, width = 7) { 

  tbl <- with(myfile, table(inner_category)[order(unique(inner_category))])
  cols <- c('cyan2','red','orange','green','dodgerblue2')
  cols <- unlist(Map(rep, cols, tbl))  
  rg <- col2rgb(cols)
  col.lt <- rgb(rg[1,], rg[2,], rg[3,], alpha = 190 / sequence(tbl), maxColorValue = 255)
  col.dk <- rgb(rg[1,], rg[2,], rg[3,], maxColorValue = 255)

  # Outside pie
  pie(myfile$share, border = "white", radius = 5 / width, col = col.lt, cex = 0.7)
  # Inside pie.  Use 'new' to get overplotting
  par(new = TRUE)
  pie(myfile$share, border = "white", radius = 4 / width, col = col.dk, labels = NA)

}

#windows()
par(mfrow=c(3,2), mar=c(4,4,2,0.5), mgp = c(1.5, 0.3, 0), tck = -0.01)

donutplotfunction(mydf)
donutplotfunction(mydf)
donutplotfunction(mydf) # etc