GIF to Amiga IFF

gif_to_iff.r

## use the magick package to read a GIF file:
library(magick)

## use AmigaFFH to convert into Amiga IFF file,
## make sure to use version 0.2.0 or newer:
library(AmigaFFH)

## Read the GIF animation we created in an earlier post:
earth <- image_read("http://3.bp.blogspot.com/-CCurVbm1ChI/VdC2NrqeeaI/AAAAAAAAx_8/lyO9mFyVhU8/s1600/globe.gif")

## convert the magick object into a list of raster objects:
earth.rst <- lapply(earth, function(x) {
  as.raster(x)
})

## reduce the number of frames:
earth.rst <- earth.rst[round(head(seq(1, length(earth.rst) + 1, length.out = 11), -1))]

## create an IFF ANIM with a 16 colour palette.
## Note that this may take some time as it is all scipted source:
earth.iff <- rasterToIFF(earth.rst,
                         depth = 4,
                         indexing = function(x, length.out)
                           index.colours(x, length.out, dither = "floyd"))

## save to an IFF file:
write.iff(earth.iff, "earth.iff")