Add a new function to add array and pixel coordinates from the Samui …

…workflow to a SpatialExperiment. For now, just get the roxygen skeleton in place, and just start to read in the transformed spatial coordinates

R/add_array_coords.R

@@ -0,0 +1,57 @@
+#' Add transformed array and pixel coordinates to a \code{SpatialExperiment}
+#'
+#' Given a \code{SpatialExperiment}, sample information, and coordinates
+#' produced from the Samui refinement workflow, add array and pixel coordinates
+#' appropriate for the linearly transformed capture areas making up each group
+#' present in the \code{SpatialExperiment}.
+#' 
+#' Array coordinates are determined via an algorithm that fits each spot to
+#' the nearest spot on a new, imaginary, Visium-like capture area. The imaginary
+#' capture area differs from a real capture area only in its extent; array
+#' coordinates still start at 0 but may extend arbitrarily beyond the normal
+#' maximum indices of 77 and 127 to fit every capture area in each group
+#' defined in the \code{SpatialExperiment}. The goal is to return well-defined
+#' array coordinates in a consistent spatial orientation for each group, such
+#' that downstream applications, such as clustering with BayesSpace, can
+#' process each group as if it really were one capture area in the first place.
+#'
+#' @param spe A \code{SpatialExperiment}
+#' @param sample_info A \code{tibble} with columns \code{capture_area},
+#' \code{group}, and \code{spaceranger_dir}
+#' @param coords_dir A \code{character(1)} vector giving the directory
+#' containing \code{tissue_positions_[group].csv} files produced from refinement
+#' with Samui
+#' @param overwrite A \code{logical(1)} vector indicating whether to overwrite
+#' \code{spatialCoords(spe)}, and \code{colData(spe)} columns \code{array_row},
+#' \code{array_col}, \code{pixel_row_in_fullres}, and
+#' \code{pixel_col_in_fullres} with the transformed values. Note that the
+#' original values are preserved even when TRUE, in versions of
+#' \code{colData(spe)} columns ending in \code{_original}.
+#'
+#' @return A \code{SpatialExperiment} object with modified \code{colData}
+#' columns \code{array_row}, \code{array_col}, \code{pixel_row_in_fullres}, and
+#' \code{pixel_col_in_fullres}, and additional corresponding columns ending in
+#' \code{_original}
+#'
+#' @export
+#' @author Nicholas J. Eagles
+
+add_array_coords = function(spe, sample_info, coords_dir, overwrite = TRUE) {
+    all_groups = unique(sample_info$group)
+
+    #   Read in tissue positions for all groups, track group and capture area,
+    #   then merge into a single tibble
+    tissue_list = list()
+    for (i in seq(length(all_groups))) {
+        tissue_list[[i]] = file.path(
+                coords_dir,
+                sprintf('tissue_positions_%s.csv', all_groups[i])
+            ) |>
+            read_csv(show_col_types = FALSE) |>
+            mutate(
+                group = all_groups[i],
+                capture_area = str_extract(key, '_(.*)', group = 1)
+            )
+    }
+    coords = do.call(rbind, tissue_list)
+}