inst/tinytest/test-25-composite.R

In RNifti: Fast R and C++ Access to NIfTI Images

# Basic data
image <- readNifti(system.file("extdata", "example.nii.gz", package="RNifti"))
tempPath <- paste(tempfile(), "nii.gz", sep=".")

# Complex datatypes
data <- sqrt(array(as.complex(image)-468, dim=dim(image)))
complexImage <- asNifti(data, image)

expect_equal(complexImage[40,40,30], 0+10i)
expect_equal(complexImage$datatype, 1792L)
expect_equal(complexImage$bitpix, 128L)
expect_equivalent(data, unclass(as.array(complexImage)))
expect_stdout(print(complexImage), "complex")

writeNifti(complexImage, tempPath)
header <- niftiHeader(tempPath)
expect_equal(header$datatype, 1792L)
expect_equal(header$bitpix, 128L)

complexImage <- readNifti(tempPath, internal=TRUE)
expect_equal(complexImage[40,40,30], 0+10i)

# RGB datatypes
expect_equal(as.character(rgbArray(diag(3))), c("#FF0000","#00FF00","#0000FF"))
expect_equivalent(channels(diag(3),"red")[,1], c(255L,0L,0L))

k <- stats::kmeans(as.vector(image), 3L)
data <- rgbArray(k$cluster==1, k$cluster==2, k$cluster==3, dim=dim(image))
rgbImage <- asNifti(data, image)
cluster <- k$cluster[40 + 39*96 + 29*9216]
refValue <- rgbArray(diag(3))[cluster]

expect_inherits(data, "rgbArray")
expect_equal(rgbImage[40,40,30], refValue)
expect_equal(rgbImage$datatype, 128L)
expect_equal(rgbImage$bitpix, 24L)
expect_equivalent(unclass(data), unclass(as.array(rgbImage)))
expect_equivalent(channels(rgbImage,c("red","green","blue")[cluster])[40,40,30,1], 255L)

writeNifti(rgbImage, tempPath)
header <- niftiHeader(tempPath)
expect_equal(header$datatype, 128L)
expect_equal(header$bitpix, 24L)

rgbImage <- readNifti(tempPath, internal=TRUE)
expect_equal(rgbImage[40 + 39*96 + 29*9216], refValue)
expect_equal(rgbImage[40,40,30], refValue)