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73 lines
3.0 KiB
73 lines
3.0 KiB
/* Copyright (C) 2001-2017 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 <stddef.h>
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#include <stdio.h>
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#include <stdlib.h>
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/* type for greymap samples */
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typedef signed short int gm_sample_t;
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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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int dy; /* offset between scanlines (in samples);
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* can be negative */
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gm_sample_t* base; /* root of allocated data */
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gm_sample_t* map; /* points to the lower left pixel */
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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_scanline( gm, y ) ( ( gm )->map + (ptrdiff_t) ( y ) * (ptrdiff_t) ( gm )->dy )
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#define gm_index( gm, x, y ) ( gm_scanline( gm, y ) + ( x ) )
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#define gm_safe( gm, x, y ) \
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( (int) ( x ) >= 0 && (int) ( x ) < ( gm )->w && (int) ( y ) >= 0 && (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 ) += (gm_sample_t) ( 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 ) = (gm_sample_t) ( 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 ) \
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( ( gm )->w == 0 || ( gm )->h == 0 ? 0 : GM_UGET( gm, gm_bound( x, ( gm )->w ), \
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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,
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greymap_t* gm,
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const char* comment,
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int raw,
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int mode,
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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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