Consolodating description of source extraction in CHANGES.txt.

Extracted do_floodfill, playsound, draw_progressbar and RGB-to-linear functions.

src/rgblinear.c

@@ -0,0 +1,46 @@
+/*
+  rgblinear.c
+
+  For Tux Paint
+  RGB to Linear and Linear to RGB functions
+
+  Copyright (c) 2002-2006 by Bill Kendrick and others
+  bill@newbreedsoftware.com
+  http://www.newbreedsoftware.com/tuxpaint/
+
+  This program 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; either version 2 of the License, or
+  (at your option) any later version.
+
+  This program 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 this program; if not, write to the Free Software
+  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+  (See COPYING.txt)
+
+  June 14, 2002 - February 17, 2006
+  $Id$
+*/
+
+#include "rgblinear.h"
+
+unsigned char linear_to_sRGB (float linear)
+{
+  unsigned slot;
+  slot = linear*4096.0 + 0.5;
+  if(slot>4095)
+    {
+      if(linear>0.5)
+        slot = 4095;
+      else
+        slot = 0;
+    }
+  return linear_to_sRGB_table[slot];
+}
+
+