63 lines
2.6 KiB
C
63 lines
2.6 KiB
C
/* Copyright (C) 2001-2015 Peter Selinger.
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* This file is part of Potrace. It is free software and it is covered
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* by the GNU General Public License. See the file COPYING for details. */
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#ifndef GREYMAP_H
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#define GREYMAP_H
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#include <stdio.h>
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#include <stdlib.h>
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#include <stddef.h>
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/* internal format for greymaps. Note: in this format, rows are
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* ordered from bottom to top. The pixels in each row are given from
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* left to right. */
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struct greymap_s
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{
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int w; /* width, in pixels */
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int h; /* height, in pixels */
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signed short int* map; /* raw data, w*h values */
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};
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typedef struct greymap_s greymap_t;
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/* macros for accessing pixel at index (x,y). Note that the origin is
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* in the *lower* left corner. U* macros omit the bounds check. */
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#define gm_index( gm, x, y ) (&(gm)->map[(x) + (y) * (ptrdiff_t) (gm)->w])
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#define gm_safe( gm, x, \
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y ) ( (int) (x)>=0 && (int) (x)<(gm)->w && (int) (y)>=0 \
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&& (int) (y)<(gm)->h )
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#define gm_bound( x, m ) ( (x)<0 ? 0 : (x)>=(m) ? (m) - 1 : (x) )
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#define GM_UGET( gm, x, y ) ( *gm_index( gm, x, y ) )
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#define GM_UINC( gm, x, y, b ) ( *gm_index( gm, x, y ) += (short int) (b) )
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#define GM_UINV( gm, x, y ) ( *gm_index( gm, x, y ) = 255 - *gm_index( gm, x, y ) )
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#define GM_UPUT( gm, x, y, b ) ( *gm_index( gm, x, y ) = (short int) (b) )
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#define GM_GET( gm, x, y ) (gm_safe( gm, x, y ) ? GM_UGET( gm, x, y ) : 0)
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#define GM_INC( gm, x, y, b ) (gm_safe( gm, x, y ) ? GM_UINC( gm, x, y, b ) : 0)
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#define GM_INV( gm, x, y ) (gm_safe( gm, x, y ) ? GM_UINV( gm, x, y ) : 0)
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#define GM_PUT( gm, x, y, b ) (gm_safe( gm, x, y ) ? GM_UPUT( gm, x, y, b ) : 0)
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#define GM_BGET( gm, x, y ) GM_UGET( gm, gm_bound( x, gm->w ), gm_bound( y, gm->h ) )
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/* modes for cutting off out-of-range values. The following names
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* refer to winding numbers. I.e., make a pixel black if winding
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* number is nonzero, odd, or positive, respectively. We assume that 0
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* winding number corresponds to white (255). */
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#define GM_MODE_NONZERO 1
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#define GM_MODE_ODD 2
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#define GM_MODE_POSITIVE 3
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#define GM_MODE_NEGATIVE 4
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extern const char* gm_read_error;
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greymap_t* gm_new( int w, int h );
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greymap_t* gm_dup( greymap_t* gm );
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void gm_free( greymap_t* gm );
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void gm_clear( greymap_t* gm, int b );
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int gm_read( FILE* f, greymap_t** gmp );
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int gm_writepgm( FILE* f, greymap_t* gm, char* comment, int raw, int mode, double gamma );
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int gm_print( FILE* f, greymap_t* gm );
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#endif /* GREYMAP_H */
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