4813314638
* Further optimization to the colortree, now allocated in one single chunk of 4090 bytes (2051 times better than original code!). Not doing all the malloc/frees should be slightly faster, and it also helps with cache locality (the whole tree can fit in the cache). * Remove the useless color "balancing" multipliers that did more harm than good. We still need some improvements on the median cut, or maybe switch to a smarter algorithm; or add some cheats. See the JFIF quirks for an example. git-svn-id: svn://pulkomandy.tk/GrafX2/trunk@1876 416bcca6-2ee7-4201-b75f-2eb2f807beb1
77 lines
2.2 KiB
C
77 lines
2.2 KiB
C
/* vim:expandtab:ts=2 sw=2:
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*/
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/* Grafx2 - The Ultimate 256-color bitmap paint program
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Copyright 2011 Adrien Destugues
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Grafx2 is free software; you can redistribute it and/or
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modify it under the terms of the GNU General Public License
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as published by the Free Software Foundation; version 2
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of the License.
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Grafx2 is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with Grafx2; if not, see <http://www.gnu.org/licenses/>
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********************************************************************************
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24bit RGB to 8bit indexed functions
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*/
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#include "struct.h"
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/* Octree for mapping RGB to color. A bit slower than a plain conversion table in theory,
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but :
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* Faster than running a search in the palette
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* Takes less memory than the huge conversion table
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* No loss of precision
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*/
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#ifndef __COLORRED_H
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#define __COLORRED_H
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typedef struct CT_Node_s
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{
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// min
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byte Rmin;
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byte Gmin;
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byte Bmin;
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// max
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byte Rmax;
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byte Gmax;
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byte Bmax;
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// possible optimization: a cluster has either two childs or a color index.
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// if the first child is NULL, then the other can be used to store the index
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// when the tree is being built, a node may have child0 set and not child1, but not the reverse)
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// possible optimization: there can't be more than 511 clusters in the tree
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// for a 256 color picture, so use int16 as pointers and store everything in a table :
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// * makes them smaller
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// * helps with cache locality
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// Child nodes :
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// Either two indices in the colorTree array, or
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// 0 and a palette index
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// 0 is not a valid array index, because no node points to the root !
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word children[2];
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} CT_Node;
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typedef struct ColorTree_S {
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short nodecount;
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CT_Node nodes[511];
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} CT_Tree;
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CT_Tree* CT_new();
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void CT_delete(CT_Tree* t);
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byte CT_get(CT_Tree* t,byte r,byte g,byte b);
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void CT_set(CT_Tree* colorTree, byte Rmin, byte Gmin, byte Bmin,
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byte Rmax, byte Gmax, byte Bmax, byte index);
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#endif
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