From 68f6cd5dac271162d20eb82d1b06101abb88bac6 Mon Sep 17 00:00:00 2001
From: Dongdong Kong <kongdd@users.noreply.github.com>
Date: Mon, 12 Aug 2024 17:04:54 +0800
Subject: [PATCH] add `rast2colormap`

---
 DESCRIPTION    |  2 +-
 NAMESPACE      |  2 ++
 R/tools_rast.R | 17 +++++++++++++++++
 3 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/DESCRIPTION b/DESCRIPTION
index 1fa4b0c..ef6a27a 100644
--- a/DESCRIPTION
+++ b/DESCRIPTION
@@ -25,7 +25,7 @@ Suggests:
     rmarkdown,
     covr
 VignetteBuilder: knitr
-RoxygenNote: 7.2.3
+RoxygenNote: 7.3.2
 Roxygen: list(markdown = TRUE)
 Encoding: UTF-8
 Depends: 
diff --git a/NAMESPACE b/NAMESPACE
index fbf8cfb..b45e242 100644
--- a/NAMESPACE
+++ b/NAMESPACE
@@ -25,6 +25,7 @@ export(overlap_fraction)
 export(plot)
 export(rast)
 export(rast2SpatialGrid)
+export(rast2colormap)
 export(rast2poly)
 export(rast_array)
 export(rast_cellId)
@@ -43,6 +44,7 @@ export(st_range)
 export(st_read)
 export(st_rect)
 export(st_write)
+export(value2colormap)
 export(write_shp)
 import(sf)
 importFrom(data.table,as.data.table)
diff --git a/R/tools_rast.R b/R/tools_rast.R
index 009c1e1..c74a102 100644
--- a/R/tools_rast.R
+++ b/R/tools_rast.R
@@ -73,3 +73,20 @@ rast_dim <- function(f) {
 
   listk(lon, lat)
 }
+
+#' @export
+value2colormap <- function(x, brks, cols) {
+  col2dt <- function(cols) col2rgb(cols) %>% t() %>% as.data.table()
+  colormap = col2dt(cols)
+  ind   = findInterval(x, brks) # %>% summary()
+  colormap[ind, ] |> as.matrix()
+}
+
+#' @export
+rast2colormap <- function(r, brks, cols, fout = "out.tif") {
+  x = values(r)
+  r2 = c(r, r, r)
+  val = val_colormap(x, brks, colors)
+  values(r2) = val
+  writeRaster(r2, fout)
+}