diff --git a/src/colorred.c b/src/colorred.c
new file mode 100644
index 00000000..154d8ce9
--- /dev/null
+++ b/src/colorred.c
@@ -0,0 +1,126 @@
+/* vim:expandtab:ts=2 sw=2:
+*/
+/*  Grafx2 - The Ultimate 256-color bitmap paint program
+
+    Copyright 2011 Adrien Destugues
+
+    Grafx2 is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation; version 2
+    of the License.
+
+    Grafx2 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Grafx2; if not, see <http://www.gnu.org/licenses/>
+
+********************************************************************************
+
+    24bit RGB to 8bit indexed functions
+*/
+
+#include <stdlib.h>
+
+#include "colorred.h"
+
+/* Octree for mapping RGB to color. A bit slower than a plain conversion table in theory,
+but :
+  * Faster than running a search in the palette
+  * Takes less memory than the huge conversion table
+  * No loss of precision
+*/
+
+CT_Node* CT_new() {return NULL;}
+
+void CT_set(CT_Node* colorTree, byte Rmin, byte Gmin, byte Bmin,
+	byte Rmax, byte Gmax, byte Bmax, byte index)
+{
+	int i;
+	CT_Node* parent = colorTree;
+	// Create and setup node
+	CT_Node* node = malloc(sizeof(CT_Node));
+	
+	node->Rmin = Rmin;
+	node->Gmin = Gmin;
+	node->Bmin = Bmin;
+	node->Rmax = Rmax;
+	node->Gmax = Gmax;
+	node->Bmax = Bmax;
+	node->index = index;
+	
+	for(i = 0; i < 7; i++)
+		node->children[i] = NULL;
+	
+	// Now insert it in tree
+	
+	if (parent == NULL) {
+		// This is our first node.
+		colorTree = node;
+	} else for(;;) {
+		// Find where to insert ourselves
+		// (clusters are non-intersecting, so there is no need to check for that)
+		int where = 0;
+		if (parent->Rmin < node->Rmin)
+			where += 4;
+		if (parent->Gmin < node->Gmin)
+			where += 2;
+		if (parent->Bmin < node->Bmin)
+			where += 1;
+			
+		// TODO - we always insert downwards, maybe we should try to keep
+		// the tree balanced...
+			
+		if (parent->children[where] == NULL)
+		{
+			// insert!	
+			parent->children[where] = node;
+			break;
+		} else {
+			// recurse
+			parent = parent->children[where];	
+		}
+	}
+}
+
+byte CT_get(CT_Node* node, byte r, byte g, byte b)
+{	
+	int wheremin = 0;
+	int wheremax = 0;
+	
+	if (node->Rmin < r)
+		wheremin += 4;
+	if (node->Gmin < g)
+		wheremin += 2;
+	if (node->Bmin < b)
+		wheremin += 1;
+		
+	if (node->Rmax < r)
+		wheremin += 4;
+	if (node->Gmax < g)
+		wheremin += 2;
+	if (node->Bmax < b)
+		wheremin += 1;
+		
+	if (wheremin == 7 && wheremax == 0)
+	{
+		// Found it!
+		return node->index;	
+	} else {
+		return CT_get(node->children[wheremin], r, g, b);	
+	}
+}
+
+void CT_delete(CT_Node* tree)
+{
+	int i;
+	if (tree == NULL)
+		return;
+	for	(i = 0; i < 8; i++)
+	{
+		CT_delete(tree->children[i]);
+	}
+	free(tree);
+}
diff --git a/src/colorred.h b/src/colorred.h
new file mode 100644
index 00000000..6f4d4001
--- /dev/null
+++ b/src/colorred.h
@@ -0,0 +1,63 @@
+/* vim:expandtab:ts=2 sw=2:
+*/
+/*  Grafx2 - The Ultimate 256-color bitmap paint program
+
+    Copyright 2011 Adrien Destugues
+
+    Grafx2 is free software; you can redistribute it and/or
+    modify it under the terms of the GNU General Public License
+    as published by the Free Software Foundation; version 2
+    of the License.
+
+    Grafx2 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 General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with Grafx2; if not, see <http://www.gnu.org/licenses/>
+
+********************************************************************************
+
+    24bit RGB to 8bit indexed functions
+*/
+
+#include "struct.h"
+
+/* Octree for mapping RGB to color. A bit slower than a plain conversion table in theory,
+but :
+  * Faster than running a search in the palette
+  * Takes less memory than the huge conversion table
+  * No loss of precision
+*/
+
+#ifndef __COLORRED_H
+#define __COLORRED_H
+
+typedef struct CT_Node_s
+{
+	// min
+	byte Rmin;
+	byte Gmin;
+	byte Bmin;
+	
+	// max
+	byte Rmax;
+	byte Gmax;
+	byte Bmax;
+	
+	// palette index (valid iff any child is NULL)
+	byte index;
+	
+	// child nodes
+	struct CT_Node_s* children[8];
+	//rgb rgB rGb rGB Rgb RgB RGb RGB
+} CT_Node;
+
+CT_Node* CT_new();
+void CT_delete(CT_Node* t);
+byte CT_get(CT_Node* t,byte r,byte g,byte b);
+void CT_set(CT_Node* colorTree, byte Rmin, byte Gmin, byte Bmin,
+	byte Rmax, byte Gmax, byte Bmax, byte index);
+
+#endif