59 lines
2.3 KiB
C
59 lines
2.3 KiB
C
/* Copyright (C) 2001-2007 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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/* $Id: greymap.h 147 2007-04-09 00:44:09Z selinger $ */
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#ifndef PGM_H
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#define PGM_H
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#include <stdio.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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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)*(gm)->w])
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#define gm_safe(gm, x, y) ((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) += (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 /* PGM_H */
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