Why?

Although this may seem like a frivolous package, encoding data as images is one way to transmit information to a graphics device through an otherwise impenetrable barrier. This package is needed to enable extra data to pass to a graphics device when using devices based upon devout.

What’s in the box

• encode_robj_to_bytes()/decode_bytes_to_robj encode an arbitrary R object to bytes using base::serialize(). This will also compress the data if zstdlite is installed.
• encode_robj_to_png()/decode_png_to_robj encode an arbitrary R object as a png
• encode_robj_to_raster()/decode_raster_to_robj encode as a raster image
• encode_robj_to_rasterGrob()/decode_rasterGrob_to_robj() encode as a grid::rasterGrob() object

Installation

You can install from GitHub with:

# install.package('remotes')
remotes::install_github('coolbutuseless/zstdlite') # suggested. but not mandatory.
remotes::install_github('coolbutuseless/snowcrash')

Encoding a small vector as bytes

bytes <- encode_robj_to_bytes(c(1, 2, 3))
bytes

 [1] 5a 53 54 18 28 b5 2f fd 20 37 a5 01 00 74 02 58 0a 00 00 00 03 00 04 00 02
[26] 00 03 05 00 00 00 00 05 55 54 46 2d 38 00 00 00 0e 3f f0 00 00 40 08 00 00
[51] 00 00 00 00 04 04 01 2b 00 65 dc c4 f3 1c 03

decode_bytes_to_robj(bytes)

[1] 1 2 3

Encoding a data.frame as an Image Raster

This example encodes the head of the mtcars data.frame into a raster image.

ras <- encode_robj_to_raster(head(mtcars), alpha = 1)
head(ras)

     [,1]        [,2]        [,3]        [,4]        [,5]        [,6]       
[1,] "#5A550CFF" "#0064BDFF" "#5260D0FF" "#104EE6FF" "#5EE176FF" "#9D371CFF"
[2,] "#53C640FF" "#364065FF" "#5AD887FF" "#4BE71CFF" "#8C98EBFF" "#9A32C1FF"
[3,] "#543F18FF" "#1341E5FF" "#68CB46FF" "#C1EDF4FF" "#5E92DDFF" "#6C4279FF"
[4,] "#18834BFF" "#4B1695FF" "#B801FFFF" "#304003FF" "#96D4E9FF" "#6C28A9FF"
[5,] "#28392FFF" "#3E0CE2FF" "#A042E3FF" "#62B7B9FF" "#C7939FFF" "#014293FF"
[6,] "#B54CE0FF" "#207639FF" "#C0F068FF" "#8AC390FF" "#16DA0DFF" "#FD4B12FF"
     [,7]        [,8]        [,9]        [,10]       [,11]       [,12]      
[1,] "#24FF9CFF" "#32FEC7FF" "#B8A9D0FF" "#7F886CFF" "#FB2A00FF" "#904700FF"
[2,] "#3CEEF6FF" "#598FA3FF" "#306627FF" "#C7187CFF" "#7F1600FF" "#508100FF"
[3,] "#36DBAEFF" "#D465DBFF" "#688F62FF" "#FF4D3FFF" "#4E0100FF" "#906D00FF"
[4,] "#001585FF" "#23DFA5FF" "#E1C85BFF" "#EFA33BFF" "#7BD600FF" "#3F1100FF"
[5,] "#40FF8EFF" "#8A10A0FF" "#C276E1FF" "#BFBBE6FF" "#F62C00FF" "#131500FF"
[6,] "#00B355FF" "#F6A58AFF" "#A1C042FF" "#84B1DEFF" "#EDA500FF" "#2E5400FF"
     [,13]      
[1,] "#7DA000FF"
[2,] "#DCC800FF"
[3,] "#922500FF"
[4,] "#A8F000FF"
[5,] "#340200FF"
[6,] "#242900FF"

plot(ras, interpolate = FALSE)

decode_raster_to_robj(ras)

                   mpg cyl disp  hp drat    wt  qsec vs am gear carb
Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
Hornet Sportabout 18.7   8  360 175 3.15 3.440 17.02  0  0    3    2
Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1

Encoding a Function as a grid::rasterGrob()

This example encodes the rle() function into a rasterGrob() object.

raster_grob <- encode_robj_to_rasterGrob(rle, alpha = 1)
grid::grid.draw(raster_grob)

decode_rasterGrob_to_robj(raster_grob)

function (x) 
{
    if (!is.vector(x) && !is.list(x)) 
        stop("'x' must be a vector of an atomic type")
    n <- length(x)
    if (n == 0L) 
        return(structure(list(lengths = integer(), values = x), 
            class = "rle"))
    y <- x[-1L] != x[-n]
    i <- c(which(y | is.na(y)), n)
    structure(list(lengths = diff(c(0L, i)), values = x[i]), 
        class = "rle")
}
<bytecode: 0x7fe06c1e3bf0>
<environment: namespace:base>

Encoding a ggplot2 Object as a PNG image

This example encodes a full ggplot code object in a PNG image file.

#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Create a plot ojbect
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
library(ggplot2)
p <- ggplot(mtcars) + 
  geom_point(aes(mpg, wt))


#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
# Save the ggplot2 object as a PNG image
#~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
png_file <- "/tmp/test.png"
encode_robj_to_png(p, filename = png_file, alpha = 1)

p <- decode_png_to_robj("/tmp/test.png") 

p + 
  theme_bw() + 
  labs(title = "Decoded plot object")

snowcrash - by Neal Stephenson

This package is named after Snow Crash, a sci-fi book by Neal Stephenson where events are set in motion by someone viewing an image of encoded information.

“You saw the whole thing,” Da5id says. “A fixed pattern of black-and-white pixels, fairly high-resolution. Just a few hundred thousand ones and zeroes for me to look at.”

“So in other words, someone just exposed your optic nerve to what, maybe a hundred thousand bytes of information,” Hiro says.

“Noise, is more like it.”

“Well, all information looks like noise until you break the code,” Hiro says.

“Why would anyone show me information in binary code? I’m not a computer. I can’t read a bitmap.”

Related Software

• base::serialize() and base::unserialize() are the built-in functions for serializing/unserializing any R object. These functions are used internally in {snowcrash}

Acknowledgements

• R Core for developing and maintaining the language.
• CRAN maintainers, for patiently shepherding packages onto CRAN and maintaining the repository