/* Copyright (C) 2001-2015 Peter Selinger.
 *  This file is part of Potrace. It is free software and it is covered
 *  by the GNU General Public License. See the file COPYING for details. */


#ifndef GREYMAP_H
#define GREYMAP_H

#include <stdio.h>
#include <stdlib.h>
#include <stddef.h>

/* internal format for greymaps. Note: in this format, rows are
 *  ordered from bottom to top. The pixels in each row are given from
 *  left to right. */

struct greymap_s
{
    int w;                  /* width, in pixels */
    int h;                  /* height, in pixels */
    signed short int* map;  /* raw data, w*h values */
};
typedef struct greymap_s greymap_t;

/* macros for accessing pixel at index (x,y). Note that the origin is
 *  in the *lower* left corner. U* macros omit the bounds check. */

#define gm_index( gm, x, y )    (&(gm)->map[(x) + (y) * (ptrdiff_t) (gm)->w])
#define gm_safe( gm, x, \
                 y )            ( (int) (x)>=0 && (int) (x)<(gm)->w && (int) (y)>=0 \
                                  && (int) (y)<(gm)->h )
#define gm_bound( x, m )        ( (x)<0 ? 0 : (x)>=(m) ? (m) - 1 : (x) )
#define GM_UGET( gm, x, y )     ( *gm_index( gm, x, y ) )
#define GM_UINC( gm, x, y, b )  ( *gm_index( gm, x, y ) += (short int) (b) )
#define GM_UINV( gm, x, y )     ( *gm_index( gm, x, y ) = 255 - *gm_index( gm, x, y ) )
#define GM_UPUT( gm, x, y, b )  ( *gm_index( gm, x, y ) = (short int) (b) )
#define GM_GET( gm, x, y )      (gm_safe( gm, x, y ) ? GM_UGET( gm, x, y ) : 0)
#define GM_INC( gm, x, y, b )   (gm_safe( gm, x, y ) ? GM_UINC( gm, x, y, b ) : 0)
#define GM_INV( gm, x, y )      (gm_safe( gm, x, y ) ? GM_UINV( gm, x, y ) : 0)
#define GM_PUT( gm, x, y, b )   (gm_safe( gm, x, y ) ? GM_UPUT( gm, x, y, b ) : 0)
#define GM_BGET( gm, x, y )     GM_UGET( gm, gm_bound( x, gm->w ), gm_bound( y, gm->h ) )

/* modes for cutting off out-of-range values. The following names
 *  refer to winding numbers. I.e., make a pixel black if winding
 *  number is nonzero, odd, or positive, respectively. We assume that 0
 *  winding number corresponds to white (255). */
#define GM_MODE_NONZERO     1
#define GM_MODE_ODD         2
#define GM_MODE_POSITIVE    3
#define GM_MODE_NEGATIVE    4

extern const char* gm_read_error;

greymap_t*  gm_new( int w, int h );
greymap_t*  gm_dup( greymap_t* gm );
void        gm_free( greymap_t* gm );
void        gm_clear( greymap_t* gm, int b );
int         gm_read( FILE* f, greymap_t** gmp );
int         gm_writepgm( FILE* f, greymap_t* gm, char* comment, int raw, int mode, double gamma );
int         gm_print( FILE* f, greymap_t* gm );

#endif /* GREYMAP_H */