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740 lines
21 KiB
740 lines
21 KiB
13 years ago
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/* Libart_LGPL - library of basic graphic primitives
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* Copyright (C) 1998-2000 Raph Levien
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Library General Public
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* License as published by the Free Software Foundation; either
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* version 2 of the License, or (at your option) any later version.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Library General Public License for more details.
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*
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* You should have received a copy of the GNU Library General Public
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* License along with this library; if not, write to the
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* Free Software Foundation, Inc., 59 Temple Place - Suite 330,
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* Boston, MA 02111-1307, USA.
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*/
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#include "config.h"
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#include "art_svp_vpath_stroke.h"
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#include <stdlib.h>
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#include <math.h>
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#include "art_misc.h"
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#include "art_vpath.h"
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#include "art_svp.h"
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#ifdef ART_USE_NEW_INTERSECTOR
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#include "art_svp_intersect.h"
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#else
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#include "art_svp_wind.h"
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#endif
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#include "art_svp_vpath.h"
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#define EPSILON 1e-6
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#define EPSILON_2 1e-12
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#define yes_OPTIMIZE_INNER
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/* Render an arc segment starting at (xc + x0, yc + y0) to (xc + x1,
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yc + y1), centered at (xc, yc), and with given radius. Both x0^2 +
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y0^2 and x1^2 + y1^2 should be equal to radius^2.
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A positive value of radius means curve to the left, negative means
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curve to the right.
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*/
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static void
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art_svp_vpath_stroke_arc (ArtVpath **p_vpath, int *pn, int *pn_max,
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double xc, double yc,
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double x0, double y0,
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double x1, double y1,
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double radius,
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double flatness)
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{
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double theta;
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double th_0, th_1;
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int n_pts;
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int i;
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double aradius;
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aradius = fabs (radius);
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theta = 2 * M_SQRT2 * sqrt (flatness / aradius);
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th_0 = atan2 (y0, x0);
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th_1 = atan2 (y1, x1);
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if (radius > 0)
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{
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/* curve to the left */
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if (th_0 < th_1) th_0 += M_PI * 2;
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n_pts = ceil ((th_0 - th_1) / theta);
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}
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else
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{
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/* curve to the right */
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if (th_1 < th_0) th_1 += M_PI * 2;
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n_pts = ceil ((th_1 - th_0) / theta);
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}
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#ifdef VERBOSE
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printf ("start %f %f; th_0 = %f, th_1 = %f, r = %f, theta = %f\n", x0, y0, th_0, th_1, radius, theta);
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#endif
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art_vpath_add_point (p_vpath, pn, pn_max,
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ART_LINETO, xc + x0, yc + y0);
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for (i = 1; i < n_pts; i++)
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{
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theta = th_0 + (th_1 - th_0) * i / n_pts;
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art_vpath_add_point (p_vpath, pn, pn_max,
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ART_LINETO, xc + cos (theta) * aradius,
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yc + sin (theta) * aradius);
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#ifdef VERBOSE
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printf ("mid %f %f\n", cos (theta) * radius, sin (theta) * radius);
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#endif
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}
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art_vpath_add_point (p_vpath, pn, pn_max,
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ART_LINETO, xc + x1, yc + y1);
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#ifdef VERBOSE
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printf ("end %f %f\n", x1, y1);
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#endif
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}
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/* Assume that forw and rev are at point i0. Bring them to i1,
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joining with the vector i1 - i2.
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This used to be true, but isn't now that the stroke_raw code is
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filtering out (near)zero length vectors: {It so happens that all
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invocations of this function maintain the precondition i1 = i0 + 1,
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so we could decrease the number of arguments by one. We haven't
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done that here, though.}
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forw is to the line's right and rev is to its left.
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Precondition: no zero-length vectors, otherwise a divide by
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zero will happen. */
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static void
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render_seg (ArtVpath **p_forw, int *pn_forw, int *pn_forw_max,
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ArtVpath **p_rev, int *pn_rev, int *pn_rev_max,
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ArtVpath *vpath, int i0, int i1, int i2,
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ArtPathStrokeJoinType join,
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double line_width, double miter_limit, double flatness)
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{
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double dx0, dy0;
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double dx1, dy1;
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double dlx0, dly0;
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double dlx1, dly1;
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double dmx, dmy;
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double dmr2;
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double scale;
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double cross;
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#ifdef VERBOSE
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printf ("join style = %d\n", join);
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#endif
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/* The vectors of the lines from i0 to i1 and i1 to i2. */
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dx0 = vpath[i1].x - vpath[i0].x;
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dy0 = vpath[i1].y - vpath[i0].y;
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dx1 = vpath[i2].x - vpath[i1].x;
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dy1 = vpath[i2].y - vpath[i1].y;
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/* Set dl[xy]0 to the vector from i0 to i1, rotated counterclockwise
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90 degrees, and scaled to the length of line_width. */
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scale = line_width / sqrt (dx0 * dx0 + dy0 * dy0);
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dlx0 = dy0 * scale;
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dly0 = -dx0 * scale;
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/* Set dl[xy]1 to the vector from i1 to i2, rotated counterclockwise
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90 degrees, and scaled to the length of line_width. */
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scale = line_width / sqrt (dx1 * dx1 + dy1 * dy1);
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dlx1 = dy1 * scale;
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dly1 = -dx1 * scale;
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#ifdef VERBOSE
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printf ("%% render_seg: (%g, %g) - (%g, %g) - (%g, %g)\n",
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vpath[i0].x, vpath[i0].y,
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vpath[i1].x, vpath[i1].y,
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vpath[i2].x, vpath[i2].y);
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printf ("%% render_seg: d[xy]0 = (%g, %g), dl[xy]0 = (%g, %g)\n",
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dx0, dy0, dlx0, dly0);
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printf ("%% render_seg: d[xy]1 = (%g, %g), dl[xy]1 = (%g, %g)\n",
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dx1, dy1, dlx1, dly1);
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#endif
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/* now, forw's last point is expected to be colinear along d[xy]0
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to point i0 - dl[xy]0, and rev with i0 + dl[xy]0. */
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/* positive for positive area (i.e. left turn) */
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cross = dx1 * dy0 - dx0 * dy1;
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dmx = (dlx0 + dlx1) * 0.5;
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dmy = (dly0 + dly1) * 0.5;
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dmr2 = dmx * dmx + dmy * dmy;
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if (join == ART_PATH_STROKE_JOIN_MITER &&
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dmr2 * miter_limit * miter_limit < line_width * line_width)
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join = ART_PATH_STROKE_JOIN_BEVEL;
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/* the case when dmr2 is zero or very small bothers me
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(i.e. near a 180 degree angle)
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ALEX: So, we avoid the optimization when dmr2 is very small. This should
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be safe since dmx/y is only used in optimization and in MITER case, and MITER
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should be converted to BEVEL when dmr2 is very small. */
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if (dmr2 > EPSILON_2)
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{
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scale = line_width * line_width / dmr2;
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dmx *= scale;
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dmy *= scale;
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}
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if (cross * cross < EPSILON_2 && dx0 * dx1 + dy0 * dy1 >= 0)
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{
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/* going straight */
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#ifdef VERBOSE
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printf ("%% render_seg: straight\n");
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#endif
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x - dlx0, vpath[i1].y - dly0);
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x + dlx0, vpath[i1].y + dly0);
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}
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else if (cross > 0)
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{
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/* left turn, forw is outside and rev is inside */
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#ifdef VERBOSE
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printf ("%% render_seg: left\n");
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#endif
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if (
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#ifdef NO_OPTIMIZE_INNER
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0 &&
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#endif
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(dmr2 > EPSILON_2) &&
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/* check that i1 + dm[xy] is inside i0-i1 rectangle */
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(dx0 + dmx) * dx0 + (dy0 + dmy) * dy0 > 0 &&
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/* and that i1 + dm[xy] is inside i1-i2 rectangle */
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((dx1 - dmx) * dx1 + (dy1 - dmy) * dy1 > 0)
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#ifdef PEDANTIC_INNER
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&&
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/* check that i1 + dl[xy]1 is inside i0-i1 rectangle */
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(dx0 + dlx1) * dx0 + (dy0 + dly1) * dy0 > 0 &&
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/* and that i1 + dl[xy]0 is inside i1-i2 rectangle */
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((dx1 - dlx0) * dx1 + (dy1 - dly0) * dy1 > 0)
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#endif
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)
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{
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/* can safely add single intersection point */
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x + dmx, vpath[i1].y + dmy);
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}
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else
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{
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/* need to loop-de-loop the inside */
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x + dlx0, vpath[i1].y + dly0);
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x, vpath[i1].y);
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x + dlx1, vpath[i1].y + dly1);
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}
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if (join == ART_PATH_STROKE_JOIN_BEVEL)
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{
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/* bevel */
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x - dlx0, vpath[i1].y - dly0);
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x - dlx1, vpath[i1].y - dly1);
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}
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else if (join == ART_PATH_STROKE_JOIN_MITER)
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{
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x - dmx, vpath[i1].y - dmy);
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}
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else if (join == ART_PATH_STROKE_JOIN_ROUND)
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art_svp_vpath_stroke_arc (p_forw, pn_forw, pn_forw_max,
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vpath[i1].x, vpath[i1].y,
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-dlx0, -dly0,
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-dlx1, -dly1,
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line_width,
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flatness);
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}
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else
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{
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/* right turn, rev is outside and forw is inside */
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#ifdef VERBOSE
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printf ("%% render_seg: right\n");
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#endif
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if (
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#ifdef NO_OPTIMIZE_INNER
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0 &&
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#endif
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(dmr2 > EPSILON_2) &&
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/* check that i1 - dm[xy] is inside i0-i1 rectangle */
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(dx0 - dmx) * dx0 + (dy0 - dmy) * dy0 > 0 &&
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/* and that i1 - dm[xy] is inside i1-i2 rectangle */
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((dx1 + dmx) * dx1 + (dy1 + dmy) * dy1 > 0)
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#ifdef PEDANTIC_INNER
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&&
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/* check that i1 - dl[xy]1 is inside i0-i1 rectangle */
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(dx0 - dlx1) * dx0 + (dy0 - dly1) * dy0 > 0 &&
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/* and that i1 - dl[xy]0 is inside i1-i2 rectangle */
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((dx1 + dlx0) * dx1 + (dy1 + dly0) * dy1 > 0)
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#endif
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)
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{
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/* can safely add single intersection point */
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x - dmx, vpath[i1].y - dmy);
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}
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else
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{
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/* need to loop-de-loop the inside */
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x - dlx0, vpath[i1].y - dly0);
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x, vpath[i1].y);
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art_vpath_add_point (p_forw, pn_forw, pn_forw_max,
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ART_LINETO, vpath[i1].x - dlx1, vpath[i1].y - dly1);
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}
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if (join == ART_PATH_STROKE_JOIN_BEVEL)
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{
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/* bevel */
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x + dlx0, vpath[i1].y + dly0);
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x + dlx1, vpath[i1].y + dly1);
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}
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else if (join == ART_PATH_STROKE_JOIN_MITER)
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{
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art_vpath_add_point (p_rev, pn_rev, pn_rev_max,
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ART_LINETO, vpath[i1].x + dmx, vpath[i1].y + dmy);
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}
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else if (join == ART_PATH_STROKE_JOIN_ROUND)
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art_svp_vpath_stroke_arc (p_rev, pn_rev, pn_rev_max,
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vpath[i1].x, vpath[i1].y,
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|
|
dlx0, dly0,
|
||
|
|
dlx1, dly1,
|
||
|
|
-line_width,
|
||
|
|
flatness);
|
||
|
|
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/* caps i1, under the assumption of a vector from i0 */
|
||
|
|
static void
|
||
|
|
render_cap (ArtVpath **p_result, int *pn_result, int *pn_result_max,
|
||
|
|
ArtVpath *vpath, int i0, int i1,
|
||
|
|
ArtPathStrokeCapType cap, double line_width, double flatness)
|
||
|
|
{
|
||
|
|
double dx0, dy0;
|
||
|
|
double dlx0, dly0;
|
||
|
|
double scale;
|
||
|
|
int n_pts;
|
||
|
|
int i;
|
||
|
|
|
||
|
|
dx0 = vpath[i1].x - vpath[i0].x;
|
||
|
|
dy0 = vpath[i1].y - vpath[i0].y;
|
||
|
|
|
||
|
|
/* Set dl[xy]0 to the vector from i0 to i1, rotated counterclockwise
|
||
|
|
90 degrees, and scaled to the length of line_width. */
|
||
|
|
scale = line_width / sqrt (dx0 * dx0 + dy0 * dy0);
|
||
|
|
dlx0 = dy0 * scale;
|
||
|
|
dly0 = -dx0 * scale;
|
||
|
|
|
||
|
|
#ifdef VERBOSE
|
||
|
|
printf ("cap style = %d\n", cap);
|
||
|
|
#endif
|
||
|
|
|
||
|
|
switch (cap)
|
||
|
|
{
|
||
|
|
case ART_PATH_STROKE_CAP_BUTT:
|
||
|
|
art_vpath_add_point (p_result, pn_result, pn_result_max,
|
||
|
|
ART_LINETO, vpath[i1].x - dlx0, vpath[i1].y - dly0);
|
||
|
|
art_vpath_add_point (p_result, pn_result, pn_result_max,
|
||
|
|
ART_LINETO, vpath[i1].x + dlx0, vpath[i1].y + dly0);
|
||
|
|
break;
|
||
|
|
case ART_PATH_STROKE_CAP_ROUND:
|
||
|
|
n_pts = ceil (M_PI / (2.0 * M_SQRT2 * sqrt (flatness / line_width)));
|
||
|
|
art_vpath_add_point (p_result, pn_result, pn_result_max,
|
||
|
|
ART_LINETO, vpath[i1].x - dlx0, vpath[i1].y - dly0);
|
||
|
|
for (i = 1; i < n_pts; i++)
|
||
|
|
{
|
||
|
|
double theta, c_th, s_th;
|
||
|
|
|
||
|
|
theta = M_PI * i / n_pts;
|
||
|
|
c_th = cos (theta);
|
||
|
|
s_th = sin (theta);
|
||
|
|
art_vpath_add_point (p_result, pn_result, pn_result_max,
|
||
|
|
ART_LINETO,
|
||
|
|
vpath[i1].x - dlx0 * c_th - dly0 * s_th,
|
||
|
|
vpath[i1].y - dly0 * c_th + dlx0 * s_th);
|
||
|
|
}
|
||
|
|
art_vpath_add_point (p_result, pn_result, pn_result_max,
|
||
|
|
ART_LINETO, vpath[i1].x + dlx0, vpath[i1].y + dly0);
|
||
|
|
break;
|
||
|
|
case ART_PATH_STROKE_CAP_SQUARE:
|
||
|
|
art_vpath_add_point (p_result, pn_result, pn_result_max,
|
||
|
|
ART_LINETO,
|
||
|
|
vpath[i1].x - dlx0 - dly0,
|
||
|
|
vpath[i1].y - dly0 + dlx0);
|
||
|
|
art_vpath_add_point (p_result, pn_result, pn_result_max,
|
||
|
|
ART_LINETO,
|
||
|
|
vpath[i1].x + dlx0 - dly0,
|
||
|
|
vpath[i1].y + dly0 + dlx0);
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
|
||
|
|
/**
|
||
|
|
* art_svp_from_vpath_raw: Stroke a vector path, raw version
|
||
|
|
* @vpath: #ArtVPath to stroke.
|
||
|
|
* @join: Join style.
|
||
|
|
* @cap: Cap style.
|
||
|
|
* @line_width: Width of stroke.
|
||
|
|
* @miter_limit: Miter limit.
|
||
|
|
* @flatness: Flatness.
|
||
|
|
*
|
||
|
|
* Exactly the same as art_svp_vpath_stroke(), except that the resulting
|
||
|
|
* stroke outline may self-intersect and have regions of winding number
|
||
|
|
* greater than 1.
|
||
|
|
*
|
||
|
|
* Return value: Resulting raw stroked outline in svp format.
|
||
|
|
**/
|
||
|
|
ArtVpath *
|
||
|
|
art_svp_vpath_stroke_raw (ArtVpath *vpath,
|
||
|
|
ArtPathStrokeJoinType join,
|
||
|
|
ArtPathStrokeCapType cap,
|
||
|
|
double line_width,
|
||
|
|
double miter_limit,
|
||
|
|
double flatness)
|
||
|
|
{
|
||
|
|
int begin_idx, end_idx;
|
||
|
|
int i;
|
||
|
|
ArtVpath *forw, *rev;
|
||
|
|
int n_forw, n_rev;
|
||
|
|
int n_forw_max, n_rev_max;
|
||
|
|
ArtVpath *result;
|
||
|
|
int n_result, n_result_max;
|
||
|
|
double half_lw = 0.5 * line_width;
|
||
|
|
int closed;
|
||
|
|
int last, this, next, second;
|
||
|
|
double dx, dy;
|
||
|
|
|
||
|
|
n_forw_max = 16;
|
||
|
|
forw = art_new (ArtVpath, n_forw_max);
|
||
|
|
|
||
|
|
n_rev_max = 16;
|
||
|
|
rev = art_new (ArtVpath, n_rev_max);
|
||
|
|
|
||
|
|
n_result = 0;
|
||
|
|
n_result_max = 16;
|
||
|
|
result = art_new (ArtVpath, n_result_max);
|
||
|
|
|
||
|
|
for (begin_idx = 0; vpath[begin_idx].code != ART_END; begin_idx = end_idx)
|
||
|
|
{
|
||
|
|
n_forw = 0;
|
||
|
|
n_rev = 0;
|
||
|
|
|
||
|
|
closed = (vpath[begin_idx].code == ART_MOVETO);
|
||
|
|
|
||
|
|
/* we don't know what the first point joins with until we get to the
|
||
|
|
last point and see if it's closed. So we start with the second
|
||
|
|
line in the path.
|
||
|
|
|
||
|
|
Note: this is not strictly true (we now know it's closed from
|
||
|
|
the opening pathcode), but why fix code that isn't broken?
|
||
|
|
*/
|
||
|
|
|
||
|
|
this = begin_idx;
|
||
|
|
/* skip over identical points at the beginning of the subpath */
|
||
|
|
for (i = this + 1; vpath[i].code == ART_LINETO; i++)
|
||
|
|
{
|
||
|
|
dx = vpath[i].x - vpath[this].x;
|
||
|
|
dy = vpath[i].y - vpath[this].y;
|
||
|
|
if (dx * dx + dy * dy > EPSILON_2)
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
next = i;
|
||
|
|
second = next;
|
||
|
|
|
||
|
|
/* invariant: this doesn't coincide with next */
|
||
|
|
while (vpath[next].code == ART_LINETO)
|
||
|
|
{
|
||
|
|
last = this;
|
||
|
|
this = next;
|
||
|
|
/* skip over identical points after the beginning of the subpath */
|
||
|
|
for (i = this + 1; vpath[i].code == ART_LINETO; i++)
|
||
|
|
{
|
||
|
|
dx = vpath[i].x - vpath[this].x;
|
||
|
|
dy = vpath[i].y - vpath[this].y;
|
||
|
|
if (dx * dx + dy * dy > EPSILON_2)
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
next = i;
|
||
|
|
if (vpath[next].code != ART_LINETO)
|
||
|
|
{
|
||
|
|
/* reached end of path */
|
||
|
|
/* make "closed" detection conform to PostScript
|
||
|
|
semantics (i.e. explicit closepath code rather than
|
||
|
|
just the fact that end of the path is the beginning) */
|
||
|
|
if (closed &&
|
||
|
|
vpath[this].x == vpath[begin_idx].x &&
|
||
|
|
vpath[this].y == vpath[begin_idx].y)
|
||
|
|
{
|
||
|
|
int j;
|
||
|
|
|
||
|
|
/* path is closed, render join to beginning */
|
||
|
|
render_seg (&forw, &n_forw, &n_forw_max,
|
||
|
|
&rev, &n_rev, &n_rev_max,
|
||
|
|
vpath, last, this, second,
|
||
|
|
join, half_lw, miter_limit, flatness);
|
||
|
|
|
||
|
|
#ifdef VERBOSE
|
||
|
|
printf ("%% forw %d, rev %d\n", n_forw, n_rev);
|
||
|
|
#endif
|
||
|
|
/* do forward path */
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_MOVETO, forw[n_forw - 1].x,
|
||
|
|
forw[n_forw - 1].y);
|
||
|
|
for (j = 0; j < n_forw; j++)
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_LINETO, forw[j].x,
|
||
|
|
forw[j].y);
|
||
|
|
|
||
|
|
/* do reverse path, reversed */
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_MOVETO, rev[0].x,
|
||
|
|
rev[0].y);
|
||
|
|
for (j = n_rev - 1; j >= 0; j--)
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_LINETO, rev[j].x,
|
||
|
|
rev[j].y);
|
||
|
|
}
|
||
|
|
else
|
||
|
|
{
|
||
|
|
/* path is open */
|
||
|
|
int j;
|
||
|
|
|
||
|
|
/* add to forw rather than result to ensure that
|
||
|
|
forw has at least one point. */
|
||
|
|
render_cap (&forw, &n_forw, &n_forw_max,
|
||
|
|
vpath, last, this,
|
||
|
|
cap, half_lw, flatness);
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_MOVETO, forw[0].x,
|
||
|
|
forw[0].y);
|
||
|
|
for (j = 1; j < n_forw; j++)
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_LINETO, forw[j].x,
|
||
|
|
forw[j].y);
|
||
|
|
for (j = n_rev - 1; j >= 0; j--)
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_LINETO, rev[j].x,
|
||
|
|
rev[j].y);
|
||
|
|
render_cap (&result, &n_result, &n_result_max,
|
||
|
|
vpath, second, begin_idx,
|
||
|
|
cap, half_lw, flatness);
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max,
|
||
|
|
ART_LINETO, forw[0].x,
|
||
|
|
forw[0].y);
|
||
|
|
}
|
||
|
|
}
|
||
|
|
else
|
||
|
|
render_seg (&forw, &n_forw, &n_forw_max,
|
||
|
|
&rev, &n_rev, &n_rev_max,
|
||
|
|
vpath, last, this, next,
|
||
|
|
join, half_lw, miter_limit, flatness);
|
||
|
|
}
|
||
|
|
end_idx = next;
|
||
|
|
}
|
||
|
|
|
||
|
|
art_free (forw);
|
||
|
|
art_free (rev);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
printf ("%% n_result = %d\n", n_result);
|
||
|
|
#endif
|
||
|
|
art_vpath_add_point (&result, &n_result, &n_result_max, ART_END, 0, 0);
|
||
|
|
return result;
|
||
|
|
}
|
||
|
|
|
||
|
|
#define noVERBOSE
|
||
|
|
|
||
|
|
#ifdef VERBOSE
|
||
|
|
|
||
|
|
#define XOFF 50
|
||
|
|
#define YOFF 700
|
||
|
|
|
||
|
|
static void
|
||
|
|
print_ps_vpath (ArtVpath *vpath)
|
||
|
|
{
|
||
|
|
int i;
|
||
|
|
|
||
|
|
for (i = 0; vpath[i].code != ART_END; i++)
|
||
|
|
{
|
||
|
|
switch (vpath[i].code)
|
||
|
|
{
|
||
|
|
case ART_MOVETO:
|
||
|
|
printf ("%g %g moveto\n", XOFF + vpath[i].x, YOFF - vpath[i].y);
|
||
|
|
break;
|
||
|
|
case ART_LINETO:
|
||
|
|
printf ("%g %g lineto\n", XOFF + vpath[i].x, YOFF - vpath[i].y);
|
||
|
|
break;
|
||
|
|
default:
|
||
|
|
break;
|
||
|
|
}
|
||
|
|
}
|
||
|
|
printf ("stroke showpage\n");
|
||
|
|
}
|
||
|
|
|
||
|
|
static void
|
||
|
|
print_ps_svp (ArtSVP *vpath)
|
||
|
|
{
|
||
|
|
int i, j;
|
||
|
|
|
||
|
|
printf ("%% begin\n");
|
||
|
|
for (i = 0; i < vpath->n_segs; i++)
|
||
|
|
{
|
||
|
|
printf ("%g setgray\n", vpath->segs[i].dir ? 0.7 : 0);
|
||
|
|
for (j = 0; j < vpath->segs[i].n_points; j++)
|
||
|
|
{
|
||
|
|
printf ("%g %g %s\n",
|
||
|
|
XOFF + vpath->segs[i].points[j].x,
|
||
|
|
YOFF - vpath->segs[i].points[j].y,
|
||
|
|
j ? "lineto" : "moveto");
|
||
|
|
}
|
||
|
|
printf ("stroke\n");
|
||
|
|
}
|
||
|
|
|
||
|
|
printf ("showpage\n");
|
||
|
|
}
|
||
|
|
#endif
|
||
|
|
|
||
|
|
/* Render a vector path into a stroked outline.
|
||
|
|
|
||
|
|
Status of this routine:
|
||
|
|
|
||
|
|
Basic correctness: Only miter and bevel line joins are implemented,
|
||
|
|
and only butt line caps. Otherwise, seems to be fine.
|
||
|
|
|
||
|
|
Numerical stability: We cheat (adding random perturbation). Thus,
|
||
|
|
it seems very likely that no numerical stability problems will be
|
||
|
|
seen in practice.
|
||
|
|
|
||
|
|
Speed: Should be pretty good.
|
||
|
|
|
||
|
|
Precision: The perturbation fuzzes the coordinates slightly,
|
||
|
|
but not enough to be visible. */
|
||
|
|
/**
|
||
|
|
* art_svp_vpath_stroke: Stroke a vector path.
|
||
|
|
* @vpath: #ArtVPath to stroke.
|
||
|
|
* @join: Join style.
|
||
|
|
* @cap: Cap style.
|
||
|
|
* @line_width: Width of stroke.
|
||
|
|
* @miter_limit: Miter limit.
|
||
|
|
* @flatness: Flatness.
|
||
|
|
*
|
||
|
|
* Computes an svp representing the stroked outline of @vpath. The
|
||
|
|
* width of the stroked line is @line_width.
|
||
|
|
*
|
||
|
|
* Lines are joined according to the @join rule. Possible values are
|
||
|
|
* ART_PATH_STROKE_JOIN_MITER (for mitered joins),
|
||
|
|
* ART_PATH_STROKE_JOIN_ROUND (for round joins), and
|
||
|
|
* ART_PATH_STROKE_JOIN_BEVEL (for bevelled joins). The mitered join
|
||
|
|
* is converted to a bevelled join if the miter would extend to a
|
||
|
|
* distance of more than @miter_limit * @line_width from the actual
|
||
|
|
* join point.
|
||
|
|
*
|
||
|
|
* If there are open subpaths, the ends of these subpaths are capped
|
||
|
|
* according to the @cap rule. Possible values are
|
||
|
|
* ART_PATH_STROKE_CAP_BUTT (squared cap, extends exactly to end
|
||
|
|
* point), ART_PATH_STROKE_CAP_ROUND (rounded half-circle centered at
|
||
|
|
* the end point), and ART_PATH_STROKE_CAP_SQUARE (squared cap,
|
||
|
|
* extending half @line_width past the end point).
|
||
|
|
*
|
||
|
|
* The @flatness parameter controls the accuracy of the rendering. It
|
||
|
|
* is most important for determining the number of points to use to
|
||
|
|
* approximate circular arcs for round lines and joins. In general, the
|
||
|
|
* resulting vector path will be within @flatness pixels of the "ideal"
|
||
|
|
* path containing actual circular arcs. I reserve the right to use
|
||
|
|
* the @flatness parameter to convert bevelled joins to miters for very
|
||
|
|
* small turn angles, as this would reduce the number of points in the
|
||
|
|
* resulting outline path.
|
||
|
|
*
|
||
|
|
* The resulting path is "clean" with respect to self-intersections, i.e.
|
||
|
|
* the winding number is 0 or 1 at each point.
|
||
|
|
*
|
||
|
|
* Return value: Resulting stroked outline in svp format.
|
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**/
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ArtSVP *
|
||
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art_svp_vpath_stroke (ArtVpath *vpath,
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||
|
|
ArtPathStrokeJoinType join,
|
||
|
|
ArtPathStrokeCapType cap,
|
||
|
|
double line_width,
|
||
|
|
double miter_limit,
|
||
|
|
double flatness)
|
||
|
|
{
|
||
|
|
#ifdef ART_USE_NEW_INTERSECTOR
|
||
|
|
ArtVpath *vpath_stroke;
|
||
|
|
ArtSVP *svp, *svp2;
|
||
|
|
ArtSvpWriter *swr;
|
||
|
|
|
||
|
|
vpath_stroke = art_svp_vpath_stroke_raw (vpath, join, cap,
|
||
|
|
line_width, miter_limit, flatness);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_vpath (vpath_stroke);
|
||
|
|
#endif
|
||
|
|
svp = art_svp_from_vpath (vpath_stroke);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_svp (svp);
|
||
|
|
#endif
|
||
|
|
art_free (vpath_stroke);
|
||
|
|
|
||
|
|
swr = art_svp_writer_rewind_new (ART_WIND_RULE_NONZERO);
|
||
|
|
art_svp_intersector (svp, swr);
|
||
|
|
|
||
|
|
svp2 = art_svp_writer_rewind_reap (swr);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_svp (svp2);
|
||
|
|
#endif
|
||
|
|
art_svp_free (svp);
|
||
|
|
return svp2;
|
||
|
|
#else
|
||
|
|
ArtVpath *vpath_stroke, *vpath2;
|
||
|
|
ArtSVP *svp, *svp2, *svp3;
|
||
|
|
|
||
|
|
vpath_stroke = art_svp_vpath_stroke_raw (vpath, join, cap,
|
||
|
|
line_width, miter_limit, flatness);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_vpath (vpath_stroke);
|
||
|
|
#endif
|
||
|
|
vpath2 = art_vpath_perturb (vpath_stroke);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_vpath (vpath2);
|
||
|
|
#endif
|
||
|
|
art_free (vpath_stroke);
|
||
|
|
svp = art_svp_from_vpath (vpath2);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_svp (svp);
|
||
|
|
#endif
|
||
|
|
art_free (vpath2);
|
||
|
|
svp2 = art_svp_uncross (svp);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_svp (svp2);
|
||
|
|
#endif
|
||
|
|
art_svp_free (svp);
|
||
|
|
svp3 = art_svp_rewind_uncrossed (svp2, ART_WIND_RULE_NONZERO);
|
||
|
|
#ifdef VERBOSE
|
||
|
|
print_ps_svp (svp3);
|
||
|
|
#endif
|
||
|
|
art_svp_free (svp2);
|
||
|
|
|
||
|
|
return svp3;
|
||
|
|
#endif
|
||
|
|
}
|