Generating identicons for fun and profit

identicons.R

# PHP source at http://scott.sherrillmix.com/blog/blogger/wp_identicon/
# http://www.gravatar.com/avatar/b1554c62bf1d05a4a9c48754a6619c17.png?d=identicon
# Related SO post: http://stackoverflow.com/q/24347608/489704

# Download and read in PHP source for shape creation
download.file('http://downloads.wordpress.org/plugin/wp-identicon.zip', 
              destfile=f <- tempfile())
unzip(f, exdir=tempdir())
txt <- readLines(file.path(tempdir(), 'wp-identicon', 'wp_identicon.php'), 
                 warn=FALSE)[55:98]

# Clean up and convert PHP nested arrays to R nested lists
txt <- gsub('\\$this->', '', 
            gsub('array', 'list', 
                 gsub('array\\((?!array)', 'c(', 
                      paste('list(', paste(sub(',//.*', '', txt), 
                                           collapse=','), ')'), 
                      perl=TRUE)))

identicon.units <- list(quarter=0.25, half=0.5, diagonal=sqrt(2 * 0.5^2), 
                        halfdiag=sqrt(2 * 0.5^2)/2)

# Create a list of angles and distance representing polygons
# (object dput at bottom of this gist)
identicon.shapes <- 
  lapply(eval(parse(text=txt), envir=identicon.units), function(x) {
    lapply(x, function(y) {
      do.call(rbind, y)  
    })
  })

# Function to get coordinates given angle and distance
get.coords <- function(a, d, flip='n') {
  if (!flip %in% c('h', 'v', 'n')) 
    stop('flip must be "n" (none), "h" (horizontal) or "v" (vertical)')
  d2 <- d
  if (flip=='h') d <- -d
  if (flip=='v') d2 <- -d2
  cbind(-d*cos((-a+90) * pi/180), -d2*sin((-a+90) * pi/180))
}

# Function to plot a single block
identiblock <- function(shp, col='black', bg='white', rotate=0, flip='n',
                        invert=FALSE) {
  if (!rotate %in% c(0, 90, 180, 270)) 
    stop('Rotation must be 0, 90, 180 or 270')
  plot.new()
  plot.window(xlim=c(-0.5, 0.5), ylim=c(-0.5, 0.5), xaxs='i', yaxs='i', asp=1)  
  rect(-0.5, -0.5, 0.5, 0.5, col=ifelse(isTRUE(invert), col, bg), border=NA)
  invisible(sapply(identicon.shapes[[shp]], function(x) {
    x[, 1] <- x[, 1] + rotate
    polygon(get.coords(x[, 1], x[, 2], flip=flip), 
            col=ifelse(isTRUE(invert), bg, col), border=NA)
  }))
}

identiblock(7)
identiblock(7, flip='h')
identiblock(7, rotate=90)
identiblock(7, invert=TRUE)


# All standard identicon shapes
png(f <- tempfile(fileext='.png'), width=525, height=105, type='cairo')
par(mfrow=c(3, 15), mar=rep(0.1, 4))
invisible(sapply(seq_along(identicon.shapes), function(i) {
  identiblock(i)
}))
dev.off()
file.show(f)

# Function to create an identicon
# In reality randomisation is more complicated
identicon <- function(seed) {
  if(!is.numeric(seed)) {
    require(digest)
    seed <- eval(parse(text=paste0('0x', substr(digest(seed, 'sha1'), 1, 7))))
  }
  set.seed(seed)
  shp <- c(sample(length(identicon.shapes), 2), 
           sample(c(1, 4, 8, 25, 26, 30, 34) + 1, 1))
  invert <- as.logical(rbinom(3, 1, 0.5))
  col <- paste0('#', as.hexmode(sample(0xFFFFFF, 1)))
  png(f <- tempfile(fileext='.png'), height=128, width=128, type='cairo')  
  par(mfrow=c(4, 4), mar=rep(0, 4))
  identiblock(shp[1], col=col, invert=invert[1])
  identiblock(shp[2], col=col, invert=invert[2])
  identiblock(shp[2], rotate=90, col=col, invert=invert[2])
  identiblock(shp[1], rotate=90, col=col, invert=invert[1])
  identiblock(shp[2], col=col, invert=invert[2])#, flip='h', rotate=270)
  identiblock(shp[3], col=col, invert=invert[3])
  identiblock(shp[3], col=col, invert=invert[3])
  identiblock(shp[2], rotate=270, col=col, invert=invert[2])
  identiblock(shp[2], rotate=270, col=col, invert=invert[2])
  identiblock(shp[3], col=col, invert=invert[3])
  identiblock(shp[3], col=col, invert=invert[3])
  identiblock(shp[2], col=col, invert=invert[2])#, flip='h', rotate=270)
  identiblock(shp[1], rotate=270, col=col, invert=invert[1])
  identiblock(shp[2], rotate=90, col=col, invert=invert[2])
  identiblock(shp[2], col=col, invert=invert[2])
  identiblock(shp[1], rotate=180, col=col, invert=invert[1])
  dev.off()
  file.show(f)  
}

identicon('someones@email.com')



# For safe-keeping (in case PHP source disappears):
# > dput(identicon.shapes)
# list(list(structure(c(90, 135, 225, 270, 0.5, 0.707106781186548, 
# 0.707106781186548, 0.5), .Dim = c(4L, 2L))), list(structure(c(45, 
# 135, 225, 315, 0.707106781186548, 0.707106781186548, 0.707106781186548, 
# 0.707106781186548), .Dim = c(4L, 2L))), list(structure(c(45, 
# 135, 225, 0.707106781186548, 0.707106781186548, 0.707106781186548
# ), .Dim = c(3L, 2L))), list(structure(c(90, 225, 315, 0.5, 0.707106781186548, 
# 0.707106781186548), .Dim = c(3L, 2L))), list(structure(c(0, 90, 
# 180, 270, 0.5, 0.5, 0.5, 0.5), .Dim = c(4L, 2L))), list(structure(c(0, 
# 135, 270, 315, 0.5, 0.707106781186548, 0.5, 0.707106781186548
# ), .Dim = c(4L, 2L))), list(structure(c(0, 90, 180, 0.25, 0.5, 
# 0.25), .Dim = c(3L, 2L)), structure(c(0, 315, 270, 0.25, 0.707106781186548, 
# 0.5), .Dim = c(3L, 2L)), structure(c(270, 180, 225, 0.5, 0.25, 
# 0.707106781186548), .Dim = c(3L, 2L))), list(structure(c(0, 135, 
# 270, 0.5, 0.707106781186548, 0.5), .Dim = c(3L, 2L))), list(structure(c(45, 
# 135, 225, 315, 0.353553390593274, 0.353553390593274, 0.353553390593274, 
# 0.353553390593274), .Dim = c(4L, 2L))), list(structure(c(180, 
# 225, 0, 0.5, 0.707106781186548, 0), .Dim = c(3L, 2L)), structure(c(45, 
# 90, 0, 0.707106781186548, 0.5, 0), .Dim = c(3L, 2L))), list(structure(c(90, 
# 135, 180, 0, 0.5, 0.707106781186548, 0.5, 0), .Dim = c(4L, 2L
# ))), list(structure(c(0, 180, 270, 0.5, 0.5, 0.5), .Dim = c(3L, 
# 2L))), list(structure(c(315, 225, 0, 0.707106781186548, 0.707106781186548, 
# 0), .Dim = c(3L, 2L))), list(structure(c(90, 180, 0, 0.5, 0.5, 
# 0), .Dim = c(3L, 2L))), list(structure(c(90, 135, 180, 0.5, 0.707106781186548, 
# 0.5), .Dim = c(3L, 2L))), list(structure(c(90, 135, 180, 0, 0.5, 
# 0.707106781186548, 0.5, 0), .Dim = c(4L, 2L)), structure(c(0, 
# 315, 270, 0, 0.5, 0.707106781186548, 0.5, 0), .Dim = c(4L, 2L
# ))), list(structure(c(315, 225, 0, 0.707106781186548, 0.707106781186548, 
# 0), .Dim = c(3L, 2L)), structure(c(45, 135, 0, 0.707106781186548, 
# 0.707106781186548, 0), .Dim = c(3L, 2L))), list(structure(c(90, 
# 135, 225, 0.5, 0.707106781186548, 0.707106781186548), .Dim = c(3L, 
# 2L))), list(structure(c(90, 135, 225, 0.5, 0.707106781186548, 
# 0.707106781186548), .Dim = c(3L, 2L)), structure(c(45, 90, 270, 
# 0.707106781186548, 0.5, 0.5), .Dim = c(3L, 2L))), list(structure(c(90, 
# 135, 225, 0.5, 0.707106781186548, 0.707106781186548), .Dim = c(3L, 
# 2L)), structure(c(45, 90, 0, 0.707106781186548, 0.5, 0), .Dim = c(3L, 
# 2L))), list(structure(c(135, 270, 315, 0.707106781186548, 0.5, 
# 0.707106781186548), .Dim = c(3L, 2L))), list(structure(c(180, 
# 225, 0, 0.5, 0.707106781186548, 0), .Dim = c(3L, 2L)), structure(c(45, 
# 90, 0, 0.707106781186548, 0.5, 0), .Dim = c(3L, 2L)), structure(c(0, 
# 0, 270, 0.5, 0, 0.5), .Dim = c(3L, 2L))), list(structure(c(0, 
# 315, 270, 0.25, 0.707106781186548, 0.5), .Dim = c(3L, 2L)), structure(c(270, 
# 180, 225, 0.5, 0.25, 0.707106781186548), .Dim = c(3L, 2L))), 
#     list(structure(c(0, 45, 315, 0.25, 0.707106781186548, 0.707106781186548
#     ), .Dim = c(3L, 2L)), structure(c(180, 135, 225, 0.25, 0.707106781186548, 
#     0.707106781186548), .Dim = c(3L, 2L))), list(structure(c(0, 
#     45, 315, 0.25, 0.707106781186548, 0.707106781186548), .Dim = c(3L, 
#     2L)), structure(c(180, 135, 225, 0.25, 0.707106781186548, 
#     0.707106781186548), .Dim = c(3L, 2L)), structure(c(180, 90, 
#     0, 270, 0.25, 0.5, 0.25, 0.5), .Dim = c(4L, 2L))), list(structure(c(0, 
#     90, 180, 270, 0.25, 0.25, 0.25, 0.25), .Dim = c(4L, 2L))), 
#     list(structure(c(0, 45, 315, 0.25, 0.707106781186548, 0.707106781186548
#     ), .Dim = c(3L, 2L)), structure(c(180, 135, 225, 0.25, 0.707106781186548, 
#     0.707106781186548), .Dim = c(3L, 2L)), structure(c(270, 225, 
#     315, 0.25, 0.707106781186548, 0.707106781186548), .Dim = c(3L, 
#     2L)), structure(c(90, 135, 45, 0.25, 0.707106781186548, 0.707106781186548
#     ), .Dim = c(3L, 2L))), list(structure(c(315, 225, 0, 0.707106781186548, 
#     0.707106781186548, 0), .Dim = c(3L, 2L)), structure(c(0, 
#     90, 180, 0.5, 0.5, 0.5), .Dim = c(3L, 2L))), list(structure(c(135, 
#     270, 315, 0.707106781186548, 0.5, 0.707106781186548), .Dim = c(3L, 
#     2L)), structure(c(225, 90, 45, 0.707106781186548, 0.5, 0.707106781186548
#     ), .Dim = c(3L, 2L))), list(structure(c(90, 135, 225, 0.5, 
#     0.707106781186548, 0.707106781186548), .Dim = c(3L, 2L)), 
#         structure(c(315, 45, 270, 0.707106781186548, 0.707106781186548, 
#         0.5), .Dim = c(3L, 2L))), list(structure(c(0, 45, 315, 
#     0.25, 0.707106781186548, 0.707106781186548), .Dim = c(3L, 
#     2L)), structure(c(180, 135, 225, 0.25, 0.707106781186548, 
#     0.707106781186548), .Dim = c(3L, 2L)), structure(c(270, 225, 
#     315, 0.25, 0.707106781186548, 0.707106781186548), .Dim = c(3L, 
#     2L)), structure(c(90, 135, 45, 0.25, 0.707106781186548, 0.707106781186548
#     ), .Dim = c(3L, 2L)), structure(c(0, 90, 180, 270, 0.25, 
#     0.25, 0.25, 0.25), .Dim = c(4L, 2L))), list(structure(c(0, 
#     90, 180, 270, 270, 180, 90, 0, 0.5, 0.5, 0.5, 0.5, 0.25, 
#     0.25, 0.25, 0.25), .Dim = c(8L, 2L))), list(structure(c(0, 
#     90, 180, 270, 0.25, 0.5, 0.25, 0.5), .Dim = c(4L, 2L))), 
#     list(structure(c(180, 225, 0, 0.5, 0.707106781186548, 0), .Dim = c(3L, 
#     2L)), structure(c(45, 90, 0, 0.707106781186548, 0.5, 0), .Dim = c(3L, 
#     2L)), structure(c(0, 0, 270, 0.5, 0, 0.5), .Dim = c(3L, 2L
#     )), structure(c(90, 135, 180, 0.5, 0.707106781186548, 0.5
#     ), .Dim = c(3L, 2L))), list(structure(c(0, 90, 180, 270, 
#     0, 0, 270, 180, 90, 0, 0.5, 0.5, 0.5, 0.5, 0.5, 0.25, 0.25, 
#     0.25, 0.25, 0.25), .Dim = c(10L, 2L))), list(structure(c(90, 
#     45, 0, 0.5, 0.707106781186548, 0.25), .Dim = c(3L, 2L)), 
#         structure(c(0, 315, 270, 0.5, 0.707106781186548, 0.25
#         ), .Dim = c(3L, 2L)), structure(c(270, 225, 180, 0.5, 
#         0.707106781186548, 0.25), .Dim = c(3L, 2L))), list(structure(c(90, 
#     45, 0, 0.5, 0.707106781186548, 0.25), .Dim = c(3L, 2L)), 
#         structure(c(0, 315, 270, 0.5, 0.707106781186548, 0.25
#         ), .Dim = c(3L, 2L))), list(structure(c(90, 45, 0, 0.5, 
#     0.707106781186548, 0.25), .Dim = c(3L, 2L)), structure(c(270, 
#     225, 180, 0.5, 0.707106781186548, 0.25), .Dim = c(3L, 2L))), 
#     list(structure(c(90, 225, 0, 315, 0.5, 0.707106781186548, 
#     0, 0.707106781186548), .Dim = c(4L, 2L))), list(structure(c(90, 
#     225, 0, 315, 225, 225, 315, 0.5, 0.707106781186548, 0, 0.353553390593274, 
#     0.353553390593274, 0.707106781186548, 0.707106781186548), .Dim = c(7L, 
#     2L))), list(structure(c(90, 135, 180, 0.5, 0.707106781186548, 
#     0.5), .Dim = c(3L, 2L)), structure(c(270, 315, 0, 0.5, 0.707106781186548, 
#     0.5), .Dim = c(3L, 2L))), list(structure(c(90, 135, 180, 
#     180, 0.5, 0.707106781186548, 0.5, 0.25), .Dim = c(4L, 2L)), 
#         structure(c(270, 315, 0, 0, 0.5, 0.707106781186548, 0.5, 
#         0.25), .Dim = c(4L, 2L))), list(structure(c(0, 45, 0, 
#     315, 0.5, 0.353553390593274, 0, 0.353553390593274), .Dim = c(4L, 
#     2L)), structure(c(180, 135, 0, 225, 0.5, 0.353553390593274, 
#     0, 0.353553390593274), .Dim = c(4L, 2L))), list(structure(c(0, 
#     45, 0, 315, 0.5, 0.707106781186548, 0, 0.353553390593274), .Dim = c(4L, 
#     2L)), structure(c(180, 135, 0, 225, 0.5, 0.353553390593274, 
#     0, 0.707106781186548), .Dim = c(4L, 2L))))