test_that("NIfTI objects can be created from data", { data <- array(rnorm(24), dim=c(3L,2L,4L)) image <- asNifti(data) expect_equal(ndim(data), 3L) expect_s3_class(image, "niftiImage") expect_equal(dim(image), c(3L,2L,4L)) expect_equal(pixdim(data), c(1,1,1)) expect_equal(pixdim(image), c(1,1,1)) expect_equal(pixunits(data), "Unknown") expect_equal(pixunits(image), "Unknown") expect_equal(image$datatype, 64L) }) test_that("NIfTI files can be read and written", { imagePath <- system.file("extdata", "example.nii.gz", package="RNifti") volumeImagePath <- system.file("extdata", "example_4d.nii.gz", package="RNifti") tempPath <- paste(tempfile(), "nii.gz", sep=".") expect_equal(niftiVersion(imagePath), structure(1L,names=imagePath)) expect_equal(dim(readNifti(imagePath,internal=FALSE)), c(96L,96L,60L)) expect_equal(dim(readNifti(imagePath,internal=TRUE)), c(96L,96L,60L)) expect_output(print(readNifti(imagePath,internal=TRUE)), "2.5 mm per voxel") # Non-NIfTI and missing files should return -1 expect_warning(version <- niftiVersion(system.file("COPYRIGHTS",package="RNifti"))) expect_equivalent(version, -1L) expect_warning(version <- niftiVersion(system.file("no-such-file",package="RNifti"))) expect_equivalent(version, -1L) image <- readNifti(imagePath) expect_s3_class(image, "niftiImage") expect_equal(image[40,40,30], 368) expect_equal(pixunits(image), c("mm","s")) expect_equal(pixdim(imagePath), c(2.5,2.5,2.5)) expect_equal(pixunits(imagePath), c("mm","s")) data <- as.vector(image) # strips all attributes expect_equal(pixdim(data), 1) data <- asNifti(data, image) expect_equal(pixdim(data), c(2.5,2.5,2.5)) paths <- writeNifti(image, tempPath) expect_equal(paths, c(header=tempPath,image=tempPath)) expect_equal(pixdim(readNifti(tempPath)), c(2.5,2.5,2.5)) unlink(tempPath) expect_output(print(niftiHeader(image)), "NIfTI-1 header") expect_equal(image$bitpix, 32L) writeNifti(image, tempPath, datatype="short") expect_equal(niftiHeader(tempPath)$bitpix, 16L) unlink(tempPath) # Type compression with index mapping writeNifti(image, tempPath, datatype="char") expect_equal(niftiHeader(tempPath)$datatype, 2L) compressedImage <- readNifti(tempPath) expect_equal(compressedImage$datatype, 64L) expect_equal(min(image), min(compressedImage)) expect_equal(max(image), max(compressedImage)) expect_equal(image, compressedImage, tolerance=0.01) expect_equal(round(compressedImage[40,40,30]), 363) image <- readNifti(imagePath, internal=TRUE) array <- as.array(image) expect_s3_class(image, "internalImage") expect_s3_class(image, "niftiImage") expect_equal(image[], array) expect_equal(image[,,], array) expect_equal(array[40,40,30], 368) expect_equal(image[40,40,30], 368) expect_equal(image[271048], 368) expect_identical(image[552961], NA_integer_) expect_equal(array[40,,30], image[40,,30]) expect_equal(array[40:42,,30:32], image[40:42,,30:32]) m <- matrix(c(40,40,30,42,30,32), byrow=TRUE, ncol=3) expect_equal(array[m], image[m]) expect_equal(array[c(40,42),,c(30,32)], image[c(40,42),,c(30,32)]) expect_error(dim(image) <- c(60L,96L,96L)) expect_error(pixdim(image) <- c(1,1,1)) expect_error(image[40,40,30] <- 400) # Direct access to the NIfTI data blob imageHeader <- niftiHeader(imagePath) expect_equal(RNifti:::readBlob(imagePath, 1, imageHeader$datatype, imageHeader$vox_offset + imageHeader$bitpix * 271047 / 8), 368) # Check that internal indexing still works when data scaling is in play compressedInternalImage <- readNifti(tempPath, internal=TRUE) expect_equal(round(compressedInternalImage[40,40,30]), 363) expect_equal(compressedInternalImage[271048], compressedImage[271048]) expect_equal(compressedInternalImage[40,,30], compressedImage[40,,30]) expect_equal(compressedInternalImage[c(40,42),,c(30,32)], compressedImage[c(40,42),,c(30,32)]) image <- readNifti(volumeImagePath, volumes=1:2) expect_equal(dim(image), c(96L,96L,60L,2L)) expect_equal(max(image), 2) expect_output(print(image), "x 1 s") # time units only appear for 4D+ images analyze <- analyzeHeader() expect_s3_class(analyze, "analyzeHeader") expect_output(print(analyze), "ANALYZE-7.5") expect_equal(analyze$regular, "r") }) test_that("NIfTI-2 and ANALYZE-7.5 format files can be written and read", { imagePath <- system.file("extdata", "example.nii.gz", package="RNifti") tempStem <- tempfile() tempPath <- paste(tempStem, "nii.gz", sep=".") analyzePaths <- c(header=paste(tempStem,"hdr",sep="."), image=paste(tempStem,"img",sep=".")) image <- readNifti(imagePath, internal=TRUE) paths <- writeNifti(image, tempPath, version=2) expect_equal(paths, c(header=tempPath,image=tempPath)) expect_equal(niftiVersion(tempPath), structure(2L,names=tempPath)) nifti2Image <- readNifti(tempPath, internal=TRUE) expect_output(print(niftiHeader(nifti2Image)), "NIfTI-2 header") expect_equal(nifti2Image$vox_offset, 544L) expect_equal(image[40,40,30], nifti2Image[40,40,30]) unlink(tempPath) paths <- writeAnalyze(image, analyzePaths[1]) expect_equal(paths, analyzePaths) expect_equal(niftiVersion(tempPath), structure(0L,names=tempPath)) analyzeImage <- readAnalyze(tempPath, internal=TRUE) expect_equal(image[40,40,30], analyzeImage[40,40,30]) }) test_that("image objects can be manipulated", { imagePath <- system.file("extdata", "example.nii.gz", package="RNifti") image <- readNifti(imagePath) expect_equal(image$dim, c(3L,96L,96L,60L,1L,1L,1L,1L)) pixdim(image) <- c(5,5,5) expect_equal(image$pixdim, c(-1,5,5,5,0,0,0,0)) pixunits(image) <- c("m","ms") expect_equal(image$xyzt_units, 17L) image$intent_code <- 1000L expect_equal(image$intent_code, 1000L) image <- asNifti(image, datatype="float") expect_equal(image$datatype, 16L) # Empty values are ignored (with a warning) expect_warning(image$intent_code <- integer(0)) # Only the first value will be used (with a warning) expect_warning(image$intent_code <- 1002:1005) expect_equal(image$intent_code, 1002L) # Vector-valued fields must have the right length expect_error(image$srow_x <- 1.0) image$srow_x[1] <- 1.0 expect_equal(image$srow_x[1], 1.0) image <- readNifti(imagePath, internal=TRUE) image <- RNifti:::rescaleNifti(image, c(0.5,0.5,0.5)) expect_equal(pixdim(image), c(5,5,5)) expect_warning(as.array(image), "no data") }) test_that("NIfTI objects have the expected copying semantics", { im1 <- readNifti(system.file("extdata", "example.nii.gz", package="RNifti"), internal=TRUE) im2 <- im1 # Only applies for internal images, because otherwise the data will be updated to match the R array expect_true(all(RNifti:::addresses(im1) == RNifti:::addresses(im2))) im1$intent_code <- 1000L expect_false(all(RNifti:::addresses(im1) == RNifti:::addresses(im2))) # Unwrapping and wrapping NiftiImage pointers involves copies im3 <- RNifti:::wrapPointer(RNifti:::unwrapPointer(im1)) expect_equal(niftiHeader(im1), niftiHeader(im3)) expect_s3_class(im3, "niftiImage") expect_false(all(RNifti:::addresses(im1) == RNifti:::addresses(im3))) }) test_that("NAs are preserved across datatypes", { # Original datatype is int16/short image <- readNifti(system.file("extdata", "example.nii.gz", package="RNifti")) tempPath <- paste(tempfile(), "nii.gz", sep=".") image[40,40,30] <- NA writeNifti(image, tempPath, datatype="int") expect_equal(readNifti(tempPath)[40,40,30], NA_integer_) writeNifti(image, tempPath, datatype="double") image <- readNifti(tempPath) expect_equal(image[40,40,30], NA_real_) image[42,42,32] <- NA writeNifti(image, tempPath, datatype="int") expect_equal(readNifti(tempPath)[42,42,32], NA_integer_) writeNifti(image, tempPath, datatype="short") expect_equal(readNifti(tempPath)[42,42,32], 0) })