1 files changed, 120 insertions, 0 deletions
diff --git a/libdimension/color_map.c b/libdimension/color_map.c
new file mode 100644
index 0000000..e0ddcd3
--- /dev/null
+++ b/libdimension/color_map.c
@@ -0,0 +1,120 @@
+/*************************************************************************
+ * Copyright (C) 2010 Tavian Barnes <tavianator@gmail.com>               *
+ *                                                                       *
+ * This file is part of The Dimension Library.                           *
+ *                                                                       *
+ * The Dimension Library is free software; you can redistribute it and/  *
+ * or modify it under the terms of the GNU Lesser General Public License *
+ * as published by the Free Software Foundation; either version 3 of the *
+ * License, or (at your option) any later version.                       *
+ *                                                                       *
+ * The Dimension Library is distributed in the hope that it will be      *
+ * useful, but WITHOUT ANY WARRANTY; without even the implied warranty   *
+ * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU  *
+ * Lesser General Public License for more details.                       *
+ *                                                                       *
+ * You should have received a copy of the GNU Lesser General Public      *
+ * License along with this program.  If not, see                         *
+ * <http://www.gnu.org/licenses/>.                                       *
+ *************************************************************************/
+
+#include "dimension.h"
+
+/*
+ * Color-mapped patterned pigments
+ */
+
+typedef struct dmnsn_color_map_entry {
+  double n;
+  dmnsn_color color;
+} dmnsn_color_map_entry;
+
+dmnsn_color_map *
+dmnsn_new_color_map()
+{
+  return dmnsn_new_array(sizeof(dmnsn_color_map_entry));
+}
+
+void
+dmnsn_delete_color_map(dmnsn_color_map *map)
+{
+  dmnsn_delete_array(map);
+}
+
+void
+dmnsn_add_color_map_entry(dmnsn_color_map *map, double n, dmnsn_color c)
+{
+  dmnsn_color_map_entry entry = { .n = n, .color = c };
+
+  /* Sorted insertion */
+  ssize_t i;
+  dmnsn_color_map_entry *other = dmnsn_array_last(map);
+  for (i = dmnsn_array_size(map) - 1; i >= 0; --i, --other) {
+    if (other->n <= n)
+      break;
+  }
+
+  dmnsn_array_insert(map, i + 1, &entry);
+}
+
+dmnsn_color
+dmnsn_color_map_value(const dmnsn_color_map *map, double n)
+{
+  dmnsn_color_map_entry *entry = dmnsn_array_first(map);
+
+  double n1, n2 = 0.0;
+  dmnsn_color c1, c2 = entry->color;
+
+  for (; entry <= (dmnsn_color_map_entry *)dmnsn_array_last(map); ++entry) {
+    n1 = n2;
+    c1 = c2;
+
+    n2 = entry->n;
+    c2 = entry->color;
+
+    if (n < n2) {
+      return dmnsn_color_gradient(c1, c2, (n - n1)/(n2 - n1));
+    }
+  }
+
+  return c2;
+}
+
+typedef struct dmnsn_color_map_payload {
+  dmnsn_pattern *pattern;
+  dmnsn_color_map *map;
+} dmnsn_color_map_payload;
+
+static dmnsn_color
+dmnsn_color_map_pigment_fn(const dmnsn_pigment *pigment, dmnsn_vector v)
+{
+  const dmnsn_color_map_payload *payload = pigment->ptr;
+  return dmnsn_color_map_value(payload->map,
+                               dmnsn_pattern_value(payload->pattern, v));
+}
+
+static void
+dmnsn_color_map_init_fn(dmnsn_pigment *pigment)
+{
+  dmnsn_color_map_payload *payload = pigment->ptr;
+  payload->pattern->trans = dmnsn_matrix_mul(pigment->trans,
+                                             payload->pattern->trans);
+  dmnsn_pattern_init(payload->pattern);
+}
+
+dmnsn_pigment *
+dmnsn_new_color_map_pigment(dmnsn_pattern *pattern, dmnsn_color_map *map)
+{
+  dmnsn_pigment *pigment = dmnsn_new_pigment();
+
+  dmnsn_color_map_payload *payload
+    = dmnsn_malloc(sizeof(dmnsn_color_map_payload));
+  payload->pattern = pattern;
+  payload->map     = map;
+
+  pigment->pigment_fn = &dmnsn_color_map_pigment_fn;
+  pigment->init_fn    = &dmnsn_color_map_init_fn;
+  pigment->free_fn    = &dmnsn_free;
+  pigment->ptr        = payload;
+  return pigment;
+}