star-cmap

commit 33597e0c60566d93600729a1701d3cd6495c4c40
parent 1103b0fa523e93202dc1c33ecdf0eee01dcdab90
Author: Vincent Forest <vincent.forest@meso-star.com>
Date:   Fri, 20 Mar 2020 17:15:11 +0100

Implement the scmap_fetch_color function

Diffstat:
M
src/scmap.c
 | 
94
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
M
src/scmap.h
 | 
2
+-
M
src/test_scmap.c
 | 
2
+-

3 files changed, 96 insertions(+), 2 deletions(-)
diff --git a/src/scmap.c b/src/scmap.c
@@ -175,6 +175,51 @@ error:
   goto exit;
 }
 
+static INLINE void
+fetch_color_nearest
+  (const struct scmap* scmap,
+   const size_t icol,
+   const double u,
+   double color[3])
+{
+  const size_t i = u < 0.5 ? icol*3 : (icol + 1)*3;
+  ASSERT(scmap && color && u >= 0 && u <1);
+  ASSERT(i/3 < darray_double_size_get(&scmap->palette)/3);
+  color[0] = darray_double_cdata_get(&scmap->palette)[i+0];
+  color[1] = darray_double_cdata_get(&scmap->palette)[i+1];
+  color[2] = darray_double_cdata_get(&scmap->palette)[i+2];
+}
+
+static INLINE void
+fetch_color_linear
+  (const struct scmap* scmap,
+   const size_t icol,
+   const double u,
+   double color[3])
+{
+  const size_t i = icol*3;
+  ASSERT(scmap && color && u >= 0 && u <1);
+  ASSERT(i/3 < darray_double_size_get(&scmap->palette)/3);
+
+  if(u == 0) {
+    color[0] = darray_double_cdata_get(&scmap->palette)[i+0];
+    color[1] = darray_double_cdata_get(&scmap->palette)[i+1];
+    color[2] = darray_double_cdata_get(&scmap->palette)[i+2];
+  } else {
+    const size_t j = (icol+1)*3;
+    const double* col0;
+    const double* col1;
+    ASSERT(j/3 < darray_double_size_get(&scmap->palette)/3);
+
+    col0 = darray_double_cdata_get(&scmap->palette) + i;
+    col1 = darray_double_cdata_get(&scmap->palette) + j;
+
+    color[0] = u * (col1[0] - col0[0]) + col0[0];
+    color[1] = u * (col1[1] - col0[1]) + col0[1];
+    color[2] = u * (col1[2] - col0[2]) + col0[2];
+  }
+}
+
 static void
 release_scmap(ref_T* ref)
 {
@@ -270,3 +315,52 @@ scmap_ref_put(struct scmap* scmap)
   return RES_OK;
 }
 
+res_T
+scmap_fetch_color
+  (const struct scmap* scmap,
+   const double value,
+   const enum scmap_filter filter,
+   double color[3])
+{
+  size_t ncolors;
+  size_t icol;
+  double cell;
+  double icell;
+  double u;
+  res_T res = RES_BAD_ARG;
+
+  if(!scmap || !color) {
+    res = RES_BAD_ARG;
+    goto error;
+  }
+
+  if(value < 0 || value > 1) {
+    log_err(scmap, "%s: the submitted value must be in [0, 1] -- value = %g.\n",
+      FUNC_NAME, value);
+    res = RES_BAD_ARG;
+    goto error;
+  }
+
+  ncolors = darray_double_size_get(&scmap->palette)/3;
+  cell = value * (double)(ncolors-1);
+
+  u = modf(cell, &icell);
+  icol = (size_t)icell;
+  ASSERT(icol < ncolors - 1);
+
+  switch(filter) {
+    case SCMAP_FILTER_NEAREST:
+      fetch_color_nearest(scmap, icol, u, color);
+      break;
+    case SCMAP_FILTER_LINEAR:
+      fetch_color_linear(scmap, icol, u, color);
+      break;
+    default: FATAL("Unreachable code.\n"); break;
+  }
+
+exit:
+  return res;
+error:
+  goto exit;
+}
+
diff --git a/src/scmap.h b/src/scmap.h
@@ -33,7 +33,7 @@
 #ifndef NDEBUG
   #define SCMAP(Func) ASSERT(scmap_ ## Func == RES_OK)
 #else
-  #define SCMA(Func) scmap_ ## Func
+  #define SCMAP(Func) scmap_ ## Func
 #endif
 
 enum scmap_filter {
diff --git a/src/test_scmap.c b/src/test_scmap.c
@@ -104,5 +104,5 @@ main(int argc, char** argv)
 
   logger_release(&logger);
   CHK(mem_allocated_size() == 0);
-return 0;
+  return 0;
 }