R/antsImageTypeCast.R

In stnava/ANTsR: ANTs in R: Quantification Tools for Biomedical Images

#' Cast images to either a passed pixeltype or the most precise of the inputs
#'
#' @param imageList list of images
#' @param pixeltype to cast to
#' @return list of antsImages
#' @author J Duda
#' @examples
#'
#' img <- antsImageRead(getANTsRData("rand")) %>% resampleImage(c(32, 32))
#' img2 <- antsImageRead(getANTsRData("rand"), pixeltype = "double") %>%
#'   resampleImage(c(32, 32))
#' allDoubles <- antsImageTypeCast(list(img, img2))
#' floats <- antsImageTypeCast(list(img))
#' pixeltype(img) <- "unsigned int"
#' ints <- antsImageTypeCast(list(img))
#'
#' @export
antsImageTypeCast <- function(imageList, pixeltype = NA) {
  pixTypes <- c()
  for (i in imageList) {
    pixTypes <- c(pixTypes, i@pixeltype)
  }

  if (is.na(pixeltype)) {
    pixeltype <- "unsigned char"
    for (i in pixTypes) {
      if (i == "double") {
        pixeltype <- "double"
      } else if ((i == "float") & (pixeltype != "double")) {
        pixeltype <- "float"
      } else if ((i == "unsigned int") & (pixeltype != "double") & (pixeltype != "float")) {
        pixeltype <- "unsigned int"
      }
    }
  }

  outImages <- list()
  count <- 1
  for (i in imageList) {
    if (pixTypes[count] == pixeltype) {
      outImages[[count]] <- i
    } else {
      outImages[[count]] <- antsImageClone(i, out_pixeltype = pixeltype)
    }
    count <- count + 1
  }

  return(outImages)
}