639 lines
17 KiB
C++
639 lines
17 KiB
C++
/* 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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#ifdef HAVE_CONFIG_H
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#include <config.h>
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#endif
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#include <cstdint>
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#include <limits.h>
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#include <stdio.h>
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#include <stdlib.h>
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#include <string.h>
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#ifdef HAVE_INTTYPES_H
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#include <inttypes.h>
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#endif
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#include "bitmap.h"
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#include "curve.h"
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#include "decompose.h"
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#include "lists.h"
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#include "potracelib.h"
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#include "progress.h"
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/* ---------------------------------------------------------------------- */
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/* deterministically and efficiently hash (x,y) into a pseudo-random bit */
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static inline int detrand( int x, int y )
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{
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unsigned int z;
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static const unsigned char t[256] =
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{
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/* non-linear sequence: constant term of inverse in GF(8),
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* mod x^8+x^4+x^3+x+1 */
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0,
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1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 1, 1, 1, 0, 1, 0, 1, 1, 0, 1, 0, 0, 0,
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0, 0, 0, 1, 1, 1, 0, 1, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 1, 0, 0, 0, 1, 0, 1, 1, 1, 1,
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1, 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 1, 1, 0, 0, 0, 0, 1, 0,
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1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 0, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1,
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0, 1, 0, 1, 0, 1, 0, 0, 1, 0, 0, 1, 0, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0,
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1, 0, 1, 0, 1, 0, 0, 1, 1, 0, 1, 0, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 1, 1, 1, 1, 0, 1, 1, 0, 0,
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1, 1, 0, 0, 1, 1, 0, 1, 1, 0, 0, 0, 1, 1, 1, 1, 0, 1, 0, 0, 0, 0, 1, 0, 1, 1, 1, 0, 0, 0, 1,
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0, 1, 1, 0, 0, 1, 1, 1, 0, 1, 0, 0, 1, 1, 0, 0, 1, 1, 1, 0, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 1,
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0, 1, 0, 1, 0, 1, 0,
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};
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/* 0x04b3e375 and 0x05a8ef93 are chosen to contain every possible
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* 5-bit sequence */
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z = ( ( 0x04b3e375 * x ) ^ y ) * 0x05a8ef93;
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z = t[z & 0xff] ^ t[( z >> 8 ) & 0xff] ^ t[( z >> 16 ) & 0xff] ^ t[( z >> 24 ) & 0xff];
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return z;
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}
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/* ---------------------------------------------------------------------- */
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/* auxiliary bitmap manipulations */
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/* set the excess padding to 0 */
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static void bm_clearexcess( potrace_bitmap_t* bm )
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{
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potrace_word mask;
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int y;
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if( bm->w % BM_WORDBITS != 0 )
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{
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mask = BM_ALLBITS << ( BM_WORDBITS - ( bm->w % BM_WORDBITS ) );
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for( y = 0; y < bm->h; y++ )
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{
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*bm_index( bm, bm->w, y ) &= mask;
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}
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}
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}
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struct bbox_s
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{
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int x0, x1, y0, y1; /* bounding box */
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};
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typedef struct bbox_s bbox_t;
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/* clear the bm, assuming the bounding box is set correctly (faster
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* than clearing the whole bitmap) */
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static void clear_bm_with_bbox( potrace_bitmap_t* bm, bbox_t* bbox )
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{
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int imin = ( bbox->x0 / BM_WORDBITS );
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int imax = ( ( bbox->x1 + BM_WORDBITS - 1 ) / BM_WORDBITS );
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int i, y;
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for( y = bbox->y0; y < bbox->y1; y++ )
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{
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for( i = imin; i < imax; i++ )
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{
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bm_scanline( bm, y )[i] = 0;
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}
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}
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}
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/* ---------------------------------------------------------------------- */
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/* auxiliary functions */
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/* return the "majority" value of bitmap bm at intersection (x,y). We
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* assume that the bitmap is balanced at "radius" 1. */
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static int majority( potrace_bitmap_t* bm, int x, int y )
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{
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int i, a, ct;
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for( i = 2; i < 5; i++ )
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{
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/* check at "radius" i */
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ct = 0;
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for( a = -i + 1; a <= i - 1; a++ )
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{
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ct += BM_GET( bm, x + a, y + i - 1 ) ? 1 : -1;
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ct += BM_GET( bm, x + i - 1, y + a - 1 ) ? 1 : -1;
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ct += BM_GET( bm, x + a - 1, y - i ) ? 1 : -1;
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ct += BM_GET( bm, x - i, y + a ) ? 1 : -1;
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}
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if( ct > 0 )
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{
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return 1;
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}
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else if( ct < 0 )
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{
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return 0;
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}
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}
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return 0;
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}
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/* ---------------------------------------------------------------------- */
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/* decompose image into paths */
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/* efficiently invert bits [x,infty) and [xa,infty) in line y. Here xa
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* must be a multiple of BM_WORDBITS. */
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static void xor_to_ref( potrace_bitmap_t* bm, int x, int y, int xa )
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{
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int xhi = x & - BM_WORDBITS;
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int xlo = x & ( BM_WORDBITS - 1 ); /* = x % BM_WORDBITS */
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int i;
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if( xhi < xa )
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{
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for( i = xhi; i < xa; i += BM_WORDBITS )
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{
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*bm_index( bm, i, y ) ^= BM_ALLBITS;
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}
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}
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else
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{
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for( i = xa; i < xhi; i += BM_WORDBITS )
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{
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*bm_index( bm, i, y ) ^= BM_ALLBITS;
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}
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}
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/* note: the following "if" is needed because x86 treats a<<b as
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* a<<(b&31). I spent hours looking for this bug. */
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if( xlo )
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{
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*bm_index( bm, xhi, y ) ^= ( BM_ALLBITS << ( BM_WORDBITS - xlo ) );
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}
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}
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/* a path is represented as an array of points, which are thought to
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* lie on the corners of pixels (not on their centers). The path point
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* (x,y) is the lower left corner of the pixel (x,y). Paths are
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* represented by the len/pt components of a path_t object (which
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* also stores other information about the path) */
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/* xor the given pixmap with the interior of the given path. Note: the
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* path must be within the dimensions of the pixmap. */
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static void xor_path( potrace_bitmap_t* bm, path_t* p )
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{
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int xa, x, y, k, y1;
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if( p->priv->len <= 0 )
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{
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/* a path of length 0 is silly, but legal */
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return;
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}
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y1 = p->priv->pt[p->priv->len - 1].y;
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xa = p->priv->pt[0].x & - BM_WORDBITS;
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for( k = 0; k < p->priv->len; k++ )
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{
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x = p->priv->pt[k].x;
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y = p->priv->pt[k].y;
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if( y != y1 )
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{
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/* efficiently invert the rectangle [x,xa] x [y,y1] */
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xor_to_ref( bm, x, min( y, y1 ), xa );
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y1 = y;
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}
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}
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}
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/* Find the bounding box of a given path. Path is assumed to be of
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* non-zero length. */
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static void setbbox_path( bbox_t* bbox, path_t* p )
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{
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int x, y;
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int k;
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bbox->y0 = INT_MAX;
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bbox->y1 = 0;
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bbox->x0 = INT_MAX;
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bbox->x1 = 0;
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for( k = 0; k < p->priv->len; k++ )
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{
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x = p->priv->pt[k].x;
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y = p->priv->pt[k].y;
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if( x < bbox->x0 )
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{
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bbox->x0 = x;
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}
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if( x > bbox->x1 )
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{
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bbox->x1 = x;
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}
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if( y < bbox->y0 )
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{
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bbox->y0 = y;
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}
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if( y > bbox->y1 )
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{
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bbox->y1 = y;
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}
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}
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}
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/* compute a path in the given pixmap, separating black from white.
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* Start path at the point (x0,x1), which must be an upper left corner
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* of the path. Also compute the area enclosed by the path. Return a
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* new path_t object, or NULL on error (note that a legitimate path
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* cannot have length 0). Sign is required for correct interpretation
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* of turnpolicies. */
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static path_t* findpath( potrace_bitmap_t* bm, int x0, int y0, int sign, int turnpolicy )
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{
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int x, y, dirx, diry, len, size;
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uint64_t area;
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int c, d, tmp;
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point_t* pt, * pt1;
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path_t* p = NULL;
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x = x0;
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y = y0;
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dirx = 0;
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diry = -1;
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len = size = 0;
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pt = NULL;
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area = 0;
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while( 1 )
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{
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/* add point to path */
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if( len >= size )
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{
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size += 100;
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size = (int) ( 1.3 * size );
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pt1 = (point_t*) realloc( pt, size * sizeof( point_t ) );
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if( !pt1 )
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{
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goto error;
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}
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pt = pt1;
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}
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pt[len].x = x;
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pt[len].y = y;
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len++;
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/* move to next point */
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x += dirx;
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y += diry;
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area += x * diry;
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/* path complete? */
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if( x == x0 && y == y0 )
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{
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break;
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}
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/* determine next direction */
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c = BM_GET( bm, x + ( dirx + diry - 1 ) / 2, y + ( diry - dirx - 1 ) / 2 );
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d = BM_GET( bm, x + ( dirx - diry - 1 ) / 2, y + ( diry + dirx - 1 ) / 2 );
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if( c && !d )
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{
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/* ambiguous turn */
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if( turnpolicy == POTRACE_TURNPOLICY_RIGHT
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|| ( turnpolicy == POTRACE_TURNPOLICY_BLACK && sign == '+' )
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|| ( turnpolicy == POTRACE_TURNPOLICY_WHITE && sign == '-' )
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|| ( turnpolicy == POTRACE_TURNPOLICY_RANDOM && detrand( x, y ) )
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|| ( turnpolicy == POTRACE_TURNPOLICY_MAJORITY && majority( bm, x, y ) )
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|| ( turnpolicy == POTRACE_TURNPOLICY_MINORITY && !majority( bm, x, y ) ) )
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{
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tmp = dirx; /* right turn */
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dirx = diry;
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diry = -tmp;
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}
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else
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{
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tmp = dirx; /* left turn */
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dirx = -diry;
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diry = tmp;
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}
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}
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else if( c )
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{
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/* right turn */
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tmp = dirx;
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dirx = diry;
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diry = -tmp;
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}
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else if( !d )
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{
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/* left turn */
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tmp = dirx;
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dirx = -diry;
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diry = tmp;
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}
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} /* while this path */
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/* allocate new path object */
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p = path_new();
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if( !p )
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{
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goto error;
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}
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p->priv->pt = pt;
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p->priv->len = len;
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p->area = area <= INT_MAX ? area : INT_MAX; /* avoid overflow */
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p->sign = sign;
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return p;
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error:
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free( pt );
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return NULL;
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}
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/* Give a tree structure to the given path list, based on "insideness"
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* testing. I.e., path A is considered "below" path B if it is inside
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* path B. The input pathlist is assumed to be ordered so that "outer"
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* paths occur before "inner" paths. The tree structure is stored in
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* the "childlist" and "sibling" components of the path_t
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* structure. The linked list structure is also changed so that
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* negative path components are listed immediately after their
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* positive parent. Note: some backends may ignore the tree
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* structure, others may use it e.g. to group path components. We
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* assume that in the input, point 0 of each path is an "upper left"
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* corner of the path, as returned by bm_to_pathlist. This makes it
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* easy to find an "interior" point. The bm argument should be a
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* bitmap of the correct size (large enough to hold all the paths),
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* and will be used as scratch space. Return 0 on success or -1 on
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* error with errno set. */
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static void pathlist_to_tree( path_t* plist, potrace_bitmap_t* bm )
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{
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path_t* p, * p1;
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path_t* heap, * heap1;
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path_t* cur;
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path_t* head;
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path_t** plist_hook; /* for fast appending to linked list */
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path_t** hook_in, ** hook_out; /* for fast appending to linked list */
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bbox_t bbox;
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bm_clear( bm, 0 );
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/* save original "next" pointers */
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list_forall( p, plist ) {
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p->sibling = p->next;
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p->childlist = NULL;
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}
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heap = plist;
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/* the heap holds a list of lists of paths. Use "childlist" field
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* for outer list, "next" field for inner list. Each of the sublists
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* is to be turned into a tree. This code is messy, but it is
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* actually fast. Each path is rendered exactly once. We use the
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* heap to get a tail recursive algorithm: the heap holds a list of
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* pathlists which still need to be transformed. */
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while( heap )
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{
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/* unlink first sublist */
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cur = heap;
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heap = heap->childlist;
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cur->childlist = NULL;
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/* unlink first path */
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head = cur;
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cur = cur->next;
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head->next = NULL;
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/* render path */
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xor_path( bm, head );
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setbbox_path( &bbox, head );
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/* now do insideness test for each element of cur; append it to
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* head->childlist if it's inside head, else append it to
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* head->next. */
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hook_in = &head->childlist;
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hook_out = &head->next;
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list_forall_unlink( p, cur ) {
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if( p->priv->pt[0].y <= bbox.y0 )
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{
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list_insert_beforehook( p, hook_out );
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/* append the remainder of the list to hook_out */
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*hook_out = cur;
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break;
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}
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if( BM_GET( bm, p->priv->pt[0].x, p->priv->pt[0].y - 1 ) )
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{
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list_insert_beforehook( p, hook_in );
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}
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else
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{
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list_insert_beforehook( p, hook_out );
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}
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}
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/* clear bm */
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clear_bm_with_bbox( bm, &bbox );
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/* now schedule head->childlist and head->next for further
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* processing */
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if( head->next )
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{
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head->next->childlist = heap;
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heap = head->next;
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}
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if( head->childlist )
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{
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head->childlist->childlist = heap;
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heap = head->childlist;
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}
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}
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/* copy sibling structure from "next" to "sibling" component */
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p = plist;
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while( p )
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{
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p1 = p->sibling;
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p->sibling = p->next;
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p = p1;
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}
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/* reconstruct a new linked list ("next") structure from tree
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* ("childlist", "sibling") structure. This code is slightly messy,
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* because we use a heap to make it tail recursive: the heap
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* contains a list of childlists which still need to be
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* processed. */
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heap = plist;
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if( heap )
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{
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heap->next = NULL; /* heap is a linked list of childlists */
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}
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plist = NULL;
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plist_hook = &plist;
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while( heap )
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{
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heap1 = heap->next;
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for( p = heap; p; p = p->sibling )
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{
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/* p is a positive path */
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/* append to linked list */
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list_insert_beforehook( p, plist_hook );
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/* go through its children */
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for( p1 = p->childlist; p1; p1 = p1->sibling )
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{
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/* append to linked list */
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list_insert_beforehook( p1, plist_hook );
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/* append its childlist to heap, if non-empty */
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if( p1->childlist )
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{
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list_append( path_t, heap1, p1->childlist );
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}
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}
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}
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heap = heap1;
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}
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}
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/* find the next set pixel in a row <= y. Pixels are searched first
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* left-to-right, then top-down. In other words, (x,y)<(x',y') if y>y'
|
|
* or y=y' and x<x'. If found, return 0 and store pixel in
|
|
* (*xp,*yp). Else return 1. Note that this function assumes that
|
|
* excess bytes have been cleared with bm_clearexcess. */
|
|
static int findnext( potrace_bitmap_t* bm, int* xp, int* yp )
|
|
{
|
|
int x;
|
|
int y;
|
|
int x0;
|
|
|
|
x0 = ( *xp ) & ~( BM_WORDBITS - 1 );
|
|
|
|
for( y = *yp; y >= 0; y-- )
|
|
{
|
|
for( x = x0; x < bm->w && x >= 0; x += (unsigned) BM_WORDBITS )
|
|
{
|
|
if( *bm_index( bm, x, y ) )
|
|
{
|
|
while( !BM_GET( bm, x, y ) )
|
|
{
|
|
x++;
|
|
}
|
|
|
|
/* found */
|
|
*xp = x;
|
|
*yp = y;
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
x0 = 0;
|
|
}
|
|
|
|
/* not found */
|
|
return 1;
|
|
}
|
|
|
|
|
|
/* Decompose the given bitmap into paths. Returns a linked list of
|
|
* path_t objects with the fields len, pt, area, sign filled
|
|
* in. Returns 0 on success with plistp set, or -1 on error with errno
|
|
* set. */
|
|
|
|
int bm_to_pathlist( const potrace_bitmap_t* bm, path_t** plistp, const potrace_param_t* param,
|
|
progress_t* progress )
|
|
{
|
|
int x;
|
|
int y;
|
|
path_t* p;
|
|
path_t* plist = NULL; /* linked list of path objects */
|
|
path_t** plist_hook = &plist; /* used to speed up appending to linked list */
|
|
potrace_bitmap_t* bm1 = NULL;
|
|
int sign;
|
|
|
|
bm1 = bm_dup( bm );
|
|
|
|
if( !bm1 )
|
|
{
|
|
goto error;
|
|
}
|
|
|
|
/* be sure the byte padding on the right is set to 0, as the fast
|
|
* pixel search below relies on it */
|
|
bm_clearexcess( bm1 );
|
|
|
|
/* iterate through components */
|
|
x = 0;
|
|
y = bm1->h - 1;
|
|
|
|
while( findnext( bm1, &x, &y ) == 0 )
|
|
{
|
|
/* calculate the sign by looking at the original */
|
|
sign = BM_GET( bm, x, y ) ? '+' : '-';
|
|
|
|
/* calculate the path */
|
|
p = findpath( bm1, x, y + 1, sign, param->turnpolicy );
|
|
|
|
if( p == NULL )
|
|
{
|
|
goto error;
|
|
}
|
|
|
|
/* update buffered image */
|
|
xor_path( bm1, p );
|
|
|
|
/* if it's a turd, eliminate it, else append it to the list */
|
|
if( p->area <= param->turdsize )
|
|
{
|
|
path_free( p );
|
|
}
|
|
else
|
|
{
|
|
list_insert_beforehook( p, plist_hook );
|
|
}
|
|
|
|
if( bm1->h > 0 )
|
|
{
|
|
/* to be sure */
|
|
progress_update( 1 - y / (double) bm1->h, progress );
|
|
}
|
|
}
|
|
|
|
pathlist_to_tree( plist, bm1 );
|
|
bm_free( bm1 );
|
|
*plistp = plist;
|
|
|
|
progress_update( 1.0, progress );
|
|
|
|
return 0;
|
|
|
|
error:
|
|
bm_free( bm1 );
|
|
list_forall_unlink( p, plist ) {
|
|
path_free( p );
|
|
}
|
|
return -1;
|
|
}
|