81 lines
2.9 KiB
C
81 lines
2.9 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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#ifndef CURVE_H
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#define CURVE_H
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#include "auxiliary.h"
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/* vertex is c[1] for tag=POTRACE_CORNER, and the intersection of
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* .c[-1][2]..c[0] and c[1]..c[2] for tag=POTRACE_CURVETO. alpha is only
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* defined for tag=POTRACE_CURVETO and is the alpha parameter of the curve:
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* .c[-1][2]..c[0] = alpha*(.c[-1][2]..vertex), and
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* c[2]..c[1] = alpha*(c[2]..vertex).
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* Beta is so that (.beta[i])[.vertex[i],.vertex[i+1]] = .c[i][2].
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*/
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struct privcurve_s
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{
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int n; /* number of segments */
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int* tag; /* tag[n]: POTRACE_CORNER or POTRACE_CURVETO */
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dpoint_t( * c )[3]; /* c[n][i]: control points.
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* c[n][0] is unused for tag[n]=POTRACE_CORNER */
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/* the remainder of this structure is special to privcurve, and is
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* used in EPS debug output and special EPS "short coding". These
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* fields are valid only if "alphacurve" is set. */
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int alphacurve; /* have the following fields been initialized? */
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dpoint_t* vertex; /* for POTRACE_CORNER, this equals c[1] */
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double* alpha; /* only for POTRACE_CURVETO */
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double* alpha0; /* "uncropped" alpha parameter - for debug output only */
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double* beta;
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};
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typedef struct privcurve_s privcurve_t;
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struct sums_s
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{
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double x;
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double y;
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double x2;
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double xy;
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double y2;
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};
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typedef struct sums_s sums_t;
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/* the path structure is filled in with information about a given path
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* as it is accumulated and passed through the different stages of the
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* Potrace algorithm. Backends only need to read the fcurve and fm
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* fields of this data structure, but debugging backends may read
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* other fields. */
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struct potrace_privpath_s
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{
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int len;
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point_t* pt; /* pt[len]: path as extracted from bitmap */
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int* lon; /* lon[len]: (i,lon[i]) = longest straight line from i */
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int x0, y0; /* origin for sums */
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sums_t* sums; /* sums[len+1]: cache for fast summing */
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int m; /* length of optimal polygon */
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int* po; /* po[m]: optimal polygon */
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privcurve_t curve; /* curve[m]: array of curve elements */
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privcurve_t ocurve; /* ocurve[om]: array of curve elements */
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privcurve_t* fcurve; /* final curve: this points to either curve or
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* ocurve. Do not free this separately. */
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};
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typedef struct potrace_privpath_s potrace_privpath_t;
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/* shorter names */
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typedef potrace_privpath_t privpath_t;
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typedef potrace_path_t path_t;
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path_t* path_new( void );
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void path_free( path_t* p );
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void pathlist_free( path_t* plist );
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int privcurve_init( privcurve_t* curve, int n );
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void privcurve_to_curve( privcurve_t* pc, potrace_curve_t* c );
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#endif /* CURVE_H */
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