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129 lines
4.2 KiB
129 lines
4.2 KiB
/* Pixel and tile functions for xcftools
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*
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* Copyright (C) 2006 Henning Makholm
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of version 2 of the GNU General Public License as
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* published by the Free Software Foundation.
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*
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* This program 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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef PIXELS_H
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#define PIXELS_H
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#include "xcftools.h"
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/* MACROS FOR INTERNAL PIXEL ORDERING HERE */
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/*=========================================*/
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/* In principle the internal representation of pixels may change.
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* - this was supposed to allow an optimization where a layer could
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* be represented as a pointer into the mmapped xcf file, if
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* alignment, bpp, and endianness agreed (the point was that the
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* pixel representation had to agree with the endianness).
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*
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* However, it turns out that the current Gimp _always_ saves images
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* with RLE encoding of tiles, so such an effort would be in vain.
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*
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* Just for modularity, nevertheless try to isolate knowledge of
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* the RGBA-to-machine-word packing in this section of the
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* header file. Define new macros if necessary.
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*
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* Given that we don't have to agree with the uncompressed
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* RLE format, we choose to have the alpha in the _least_
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* significant byte on all archs - it is tested and used more
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* often than the visible channels.
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*/
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typedef uint32_t rgba ;
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#define ALPHA_SHIFT 0
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#define RED_SHIFT 8
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#define GREEN_SHIFT 16
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#define BLUE_SHIFT 24
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#define ALPHA(rgba) ((uint8_t)(rgba))
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#define FULLALPHA(rgba) ((uint8_t)(rgba) == 255)
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#define NULLALPHA(rgba) ((uint8_t)(rgba) == 0)
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#define NEWALPHA(rgb,a) (((rgba)(rgb) & 0xFFFFFF00) + (a))
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#ifdef PRECOMPUTED_SCALETABLE
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extern const uint8_t scaletable[256][256] ;
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#define INIT_SCALETABLE_IF(foo) ((void)0)
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#else
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extern uint8_t scaletable[256][256] ;
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extern int ok_scaletable ;
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void mk_scaletable(void);
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#define INIT_SCALETABLE_IF(foo) \
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(ok_scaletable || !(foo) || (mk_scaletable(),0) )
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#endif
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extern const rgba graytable[256] ;
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extern rgba colormap[256] ;
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extern unsigned colormapLength ;
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void initLayer(struct xcfLayer *);
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void initColormap();
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int degrayPixel(rgba); /* returns -1 for non-gray pixels */
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/* ******************************************************* */
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#define TILEXn(dim,tx) \
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((tx)==(dim).tilesx ? (dim).c.r : (dim).c.l + ((tx)*TILE_WIDTH))
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#define TILEYn(dim,ty) \
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((ty)==(dim).tilesy ? (dim).c.b : (dim).c.t + ((ty)*TILE_HEIGHT))
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#if __i386__
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/* This is probably the only common architecture where small constants
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* are more efficient for byte operations.
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*/
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typedef int8_t summary_t ;
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typedef short int refcount_t ;
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#else
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typedef int summary_t ;
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typedef int refcount_t ;
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#endif
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#define TILESUMMARY_UPTODATE 8
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#define TILESUMMARY_ALLNULL 4
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#define TILESUMMARY_ALLFULL 2
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#define TILESUMMARY_CRISP 1 /* everyting either null or full */
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struct Tile {
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refcount_t refcount ;
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summary_t summary ; /* a combination of TIMESUMMARY_FOO constatns */
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unsigned count ;
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rgba pixels[TILE_WIDTH * TILE_HEIGHT];
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};
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/* Actually, the Tile structures that get allocated many not have
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* room for that many pixels. We subtract the space for those we don't
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* use - which is Not Legal C, but ought to be portable.
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* OTOH, one can also use a static struct Tile for temporary storage.
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*/
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#define assertTileCompatibility(t1,t2) assert((t1)->count==(t2)->count)
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struct Tile *newTile(struct rect);
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struct Tile *forkTile(struct Tile*);
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void freeTile(struct Tile*);
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#define invalidateSummary(tile,mask) \
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do{ assert((tile)->refcount==1); (tile)->summary &= mask; } while(0)
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summary_t __ATTRIBUTE__((pure)) tileSummary(struct Tile *);
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void fillTile(struct Tile*,rgba);
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/* applyMask() destructively changes tile,
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* applyMask() gets ownership of mask
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*/
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void applyMask(struct Tile *tile, struct Tile *mask);
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struct Tile *getLayerTile(struct xcfLayer *,const struct rect *);
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#endif /* FLATTEN_H */
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