forked from KolibriOS/kolibrios
1375 lines
37 KiB
C
1375 lines
37 KiB
C
/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
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/* cairo - a vector graphics library with display and print output
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*
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* Copyright © 2002 University of Southern California
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* Copyright © 2011 Intel Corporation
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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 either under the terms of the GNU Lesser General Public
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* License version 2.1 as published by the Free Software Foundation
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* (the "LGPL") or, at your option, under the terms of the Mozilla
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* Public License Version 1.1 (the "MPL"). If you do not alter this
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* notice, a recipient may use your version of this file under either
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* the MPL or the LGPL.
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*
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* You should have received a copy of the LGPL along with this library
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* in the file COPYING-LGPL-2.1; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
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* You should have received a copy of the MPL along with this library
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* in the file COPYING-MPL-1.1
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.1 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
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* OF ANY KIND, either express or implied. See the LGPL or the MPL for
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* the specific language governing rights and limitations.
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*
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* The Original Code is the cairo graphics library.
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*
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* The Initial Developer of the Original Code is University of Southern
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* California.
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*
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* Contributor(s):
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* Carl D. Worth <cworth@cworth.org>
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* Chris Wilson <chris@chris-wilson.co.uk>
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*/
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#define _BSD_SOURCE /* for hypot() */
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#include "cairoint.h"
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#include "cairo-box-inline.h"
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#include "cairo-boxes-private.h"
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#include "cairo-contour-inline.h"
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#include "cairo-contour-private.h"
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#include "cairo-error-private.h"
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#include "cairo-path-fixed-private.h"
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#include "cairo-slope-private.h"
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#define DEBUG 0
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struct stroker {
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cairo_stroke_style_t style;
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#if DEBUG
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cairo_contour_t path;
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#endif
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struct stroke_contour {
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/* Note that these are not strictly contours as they may intersect */
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cairo_contour_t contour;
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} cw, ccw;
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cairo_uint64_t contour_tolerance;
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cairo_polygon_t *polygon;
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const cairo_matrix_t *ctm;
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const cairo_matrix_t *ctm_inverse;
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double tolerance;
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double spline_cusp_tolerance;
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double half_line_width;
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cairo_bool_t ctm_det_positive;
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cairo_pen_t pen;
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cairo_point_t first_point;
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cairo_bool_t has_initial_sub_path;
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cairo_bool_t has_current_face;
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cairo_stroke_face_t current_face;
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cairo_bool_t has_first_face;
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cairo_stroke_face_t first_face;
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cairo_bool_t has_bounds;
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cairo_box_t bounds;
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};
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static inline double
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normalize_slope (double *dx, double *dy);
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static void
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compute_face (const cairo_point_t *point,
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const cairo_slope_t *dev_slope,
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struct stroker *stroker,
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cairo_stroke_face_t *face);
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static cairo_uint64_t
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point_distance_sq (const cairo_point_t *p1,
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const cairo_point_t *p2)
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{
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int32_t dx = p1->x - p2->x;
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int32_t dy = p1->y - p2->y;
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return _cairo_int32x32_64_mul (dx, dx) + _cairo_int32x32_64_mul (dy, dy);
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}
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static cairo_bool_t
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within_tolerance (const cairo_point_t *p1,
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const cairo_point_t *p2,
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cairo_uint64_t tolerance)
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{
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return FALSE;
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return _cairo_int64_lt (point_distance_sq (p1, p2), tolerance);
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}
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static void
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contour_add_point (struct stroker *stroker,
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struct stroke_contour *c,
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const cairo_point_t *point)
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{
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if (! within_tolerance (point, _cairo_contour_last_point (&c->contour),
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stroker->contour_tolerance))
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_cairo_contour_add_point (&c->contour, point);
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//*_cairo_contour_last_point (&c->contour) = *point;
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}
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static void
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translate_point (cairo_point_t *point, const cairo_point_t *offset)
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{
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point->x += offset->x;
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point->y += offset->y;
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}
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static int
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slope_compare_sgn (double dx1, double dy1, double dx2, double dy2)
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{
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double c = (dx1 * dy2 - dx2 * dy1);
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if (c > 0) return 1;
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if (c < 0) return -1;
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return 0;
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}
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static inline int
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range_step (int i, int step, int max)
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{
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i += step;
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if (i < 0)
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i = max - 1;
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if (i >= max)
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i = 0;
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return i;
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}
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/*
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* Construct a fan around the midpoint using the vertices from pen between
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* inpt and outpt.
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*/
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static void
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add_fan (struct stroker *stroker,
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const cairo_slope_t *in_vector,
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const cairo_slope_t *out_vector,
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const cairo_point_t *midpt,
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cairo_bool_t clockwise,
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struct stroke_contour *c)
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{
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cairo_pen_t *pen = &stroker->pen;
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int start, stop;
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if (stroker->has_bounds &&
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! _cairo_box_contains_point (&stroker->bounds, midpt))
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return;
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assert (stroker->pen.num_vertices);
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if (clockwise) {
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_cairo_pen_find_active_cw_vertices (pen,
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in_vector, out_vector,
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&start, &stop);
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while (start != stop) {
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cairo_point_t p = *midpt;
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translate_point (&p, &pen->vertices[start].point);
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contour_add_point (stroker, c, &p);
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if (++start == pen->num_vertices)
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start = 0;
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}
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} else {
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_cairo_pen_find_active_ccw_vertices (pen,
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in_vector, out_vector,
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&start, &stop);
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while (start != stop) {
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cairo_point_t p = *midpt;
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translate_point (&p, &pen->vertices[start].point);
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contour_add_point (stroker, c, &p);
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if (start-- == 0)
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start += pen->num_vertices;
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}
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}
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}
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static int
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join_is_clockwise (const cairo_stroke_face_t *in,
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const cairo_stroke_face_t *out)
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{
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return _cairo_slope_compare (&in->dev_vector, &out->dev_vector) < 0;
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}
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static void
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inner_join (struct stroker *stroker,
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const cairo_stroke_face_t *in,
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const cairo_stroke_face_t *out,
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int clockwise)
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{
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#if 0
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cairo_point_t last;
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const cairo_point_t *p, *outpt;
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struct stroke_contour *inner;
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cairo_int64_t d_p, d_last;
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cairo_int64_t half_line_width;
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cairo_bool_t negate;
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/* XXX line segments shorter than line-width */
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if (clockwise) {
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inner = &stroker->ccw;
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outpt = &out->ccw;
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negate = 1;
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} else {
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inner = &stroker->cw;
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outpt = &out->cw;
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negate = 0;
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}
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half_line_width = CAIRO_FIXED_ONE*CAIRO_FIXED_ONE/2 * stroker->style.line_width * out->length + .5;
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/* On the inside, the previous end-point is always
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* closer to the new face by definition.
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*/
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last = *_cairo_contour_last_point (&inner->contour);
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d_last = distance_from_face (out, &last, negate);
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_cairo_contour_remove_last_point (&inner->contour);
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prev:
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if (inner->contour.chain.num_points == 0) {
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contour_add_point (stroker, inner, outpt);
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return;
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}
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p = _cairo_contour_last_point (&inner->contour);
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d_p = distance_from_face (out, p, negate);
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if (_cairo_int64_lt (d_p, half_line_width) &&
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!_cairo_int64_negative (distance_along_face (out, p)))
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{
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last = *p;
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d_last = d_p;
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_cairo_contour_remove_last_point (&inner->contour);
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goto prev;
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}
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compute_inner_joint (&last, d_last, p, d_p, half_line_width);
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contour_add_point (stroker, inner, &last);
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#else
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const cairo_point_t *outpt;
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struct stroke_contour *inner;
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if (clockwise) {
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inner = &stroker->ccw;
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outpt = &out->ccw;
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} else {
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inner = &stroker->cw;
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outpt = &out->cw;
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}
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contour_add_point (stroker, inner, &in->point);
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contour_add_point (stroker, inner, outpt);
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#endif
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}
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static void
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inner_close (struct stroker *stroker,
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const cairo_stroke_face_t *in,
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cairo_stroke_face_t *out)
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{
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#if 0
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cairo_point_t last;
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const cairo_point_t *p, *outpt, *inpt;
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struct stroke_contour *inner;
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struct _cairo_contour_chain *chain;
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/* XXX line segments shorter than line-width */
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if (join_is_clockwise (in, out)) {
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inner = &stroker->ccw;
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outpt = &in->ccw;
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inpt = &out->ccw;
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} else {
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inner = &stroker->cw;
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outpt = &in->cw;
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inpt = &out->cw;
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}
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if (inner->contour.chain.num_points == 0) {
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contour_add_point (stroker, inner, &in->point);
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contour_add_point (stroker, inner, inpt);
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*_cairo_contour_first_point (&inner->contour) =
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*_cairo_contour_last_point (&inner->contour);
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return;
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}
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line_width = stroker->style.line_width/2;
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line_width *= CAIRO_FIXED_ONE;
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d_last = sign * distance_from_face (out, outpt);
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last = *outpt;
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for (chain = &inner->contour.chain; chain; chain = chain->next) {
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for (i = 0; i < chain->num_points; i++) {
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p = &chain->points[i];
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if ((d_p = sign * distance_from_face (in, p)) >= line_width &&
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distance_from_edge (stroker, inpt, &last, p) < line_width)
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{
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goto out;
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}
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if (p->x != last.x || p->y != last.y) {
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last = *p;
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d_last = d_p;
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}
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}
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}
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out:
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if (d_p != d_last) {
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double dot = (line_width - d_last) / (d_p - d_last);
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last.x += dot * (p->x - last.x);
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last.y += dot * (p->y - last.y);
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}
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*_cairo_contour_last_point (&inner->contour) = last;
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for (chain = &inner->contour.chain; chain; chain = chain->next) {
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for (i = 0; i < chain->num_points; i++) {
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cairo_point_t *pp = &chain->points[i];
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if (pp == p)
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return;
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*pp = last;
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}
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}
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#else
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const cairo_point_t *inpt;
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struct stroke_contour *inner;
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if (join_is_clockwise (in, out)) {
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inner = &stroker->ccw;
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inpt = &out->ccw;
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} else {
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inner = &stroker->cw;
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inpt = &out->cw;
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}
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contour_add_point (stroker, inner, &in->point);
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contour_add_point (stroker, inner, inpt);
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*_cairo_contour_first_point (&inner->contour) =
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*_cairo_contour_last_point (&inner->contour);
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#endif
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}
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static void
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outer_close (struct stroker *stroker,
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const cairo_stroke_face_t *in,
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const cairo_stroke_face_t *out)
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{
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const cairo_point_t *inpt, *outpt;
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struct stroke_contour *outer;
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int clockwise;
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if (in->cw.x == out->cw.x && in->cw.y == out->cw.y &&
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in->ccw.x == out->ccw.x && in->ccw.y == out->ccw.y)
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{
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return;
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}
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clockwise = join_is_clockwise (in, out);
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if (clockwise) {
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inpt = &in->cw;
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outpt = &out->cw;
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outer = &stroker->cw;
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} else {
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inpt = &in->ccw;
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outpt = &out->ccw;
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outer = &stroker->ccw;
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}
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if (within_tolerance (inpt, outpt, stroker->contour_tolerance)) {
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*_cairo_contour_first_point (&outer->contour) =
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*_cairo_contour_last_point (&outer->contour);
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return;
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}
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switch (stroker->style.line_join) {
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case CAIRO_LINE_JOIN_ROUND:
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/* construct a fan around the common midpoint */
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if ((in->dev_slope.x * out->dev_slope.x +
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in->dev_slope.y * out->dev_slope.y) < stroker->spline_cusp_tolerance)
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{
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add_fan (stroker,
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&in->dev_vector, &out->dev_vector, &in->point,
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clockwise, outer);
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break;
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}
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case CAIRO_LINE_JOIN_MITER:
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default: {
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/* dot product of incoming slope vector with outgoing slope vector */
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double in_dot_out = in->dev_slope.x * out->dev_slope.x +
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in->dev_slope.y * out->dev_slope.y;
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double ml = stroker->style.miter_limit;
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/* Check the miter limit -- lines meeting at an acute angle
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* can generate long miters, the limit converts them to bevel
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*
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* Consider the miter join formed when two line segments
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* meet at an angle psi:
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*
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* /.\
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* /. .\
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* /./ \.\
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* /./psi\.\
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*
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* We can zoom in on the right half of that to see:
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*
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* |\
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* | \ psi/2
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* | \
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* | \
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* | \
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* | \
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* miter \
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* length \
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* | \
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* | .\
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* | . \
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* |. line \
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* \ width \
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* \ \
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*
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*
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* The right triangle in that figure, (the line-width side is
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* shown faintly with three '.' characters), gives us the
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* following expression relating miter length, angle and line
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* width:
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*
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* 1 /sin (psi/2) = miter_length / line_width
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*
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* The right-hand side of this relationship is the same ratio
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* in which the miter limit (ml) is expressed. We want to know
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* when the miter length is within the miter limit. That is
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* when the following condition holds:
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*
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* 1/sin(psi/2) <= ml
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* 1 <= ml sin(psi/2)
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* 1 <= ml² sin²(psi/2)
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* 2 <= ml² 2 sin²(psi/2)
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* 2·sin²(psi/2) = 1-cos(psi)
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* 2 <= ml² (1-cos(psi))
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*
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* in · out = |in| |out| cos (psi)
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*
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* in and out are both unit vectors, so:
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*
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* in · out = cos (psi)
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*
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* 2 <= ml² (1 - in · out)
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*
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*/
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if (2 <= ml * ml * (1 + in_dot_out)) {
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double x1, y1, x2, y2;
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double mx, my;
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double dx1, dx2, dy1, dy2;
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double ix, iy;
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double fdx1, fdy1, fdx2, fdy2;
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double mdx, mdy;
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/*
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* we've got the points already transformed to device
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* space, but need to do some computation with them and
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* also need to transform the slope from user space to
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* device space
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*/
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/* outer point of incoming line face */
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x1 = _cairo_fixed_to_double (inpt->x);
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y1 = _cairo_fixed_to_double (inpt->y);
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dx1 = in->dev_slope.x;
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dy1 = in->dev_slope.y;
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/* outer point of outgoing line face */
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x2 = _cairo_fixed_to_double (outpt->x);
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y2 = _cairo_fixed_to_double (outpt->y);
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dx2 = out->dev_slope.x;
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dy2 = out->dev_slope.y;
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/*
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* Compute the location of the outer corner of the miter.
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|
* That's pretty easy -- just the intersection of the two
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* outer edges. We've got slopes and points on each
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* of those edges. Compute my directly, then compute
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* mx by using the edge with the larger dy; that avoids
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* dividing by values close to zero.
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|
*/
|
|
my = (((x2 - x1) * dy1 * dy2 - y2 * dx2 * dy1 + y1 * dx1 * dy2) /
|
|
(dx1 * dy2 - dx2 * dy1));
|
|
if (fabs (dy1) >= fabs (dy2))
|
|
mx = (my - y1) * dx1 / dy1 + x1;
|
|
else
|
|
mx = (my - y2) * dx2 / dy2 + x2;
|
|
|
|
/*
|
|
* When the two outer edges are nearly parallel, slight
|
|
* perturbations in the position of the outer points of the lines
|
|
* caused by representing them in fixed point form can cause the
|
|
* intersection point of the miter to move a large amount. If
|
|
* that moves the miter intersection from between the two faces,
|
|
* then draw a bevel instead.
|
|
*/
|
|
|
|
ix = _cairo_fixed_to_double (in->point.x);
|
|
iy = _cairo_fixed_to_double (in->point.y);
|
|
|
|
/* slope of one face */
|
|
fdx1 = x1 - ix; fdy1 = y1 - iy;
|
|
|
|
/* slope of the other face */
|
|
fdx2 = x2 - ix; fdy2 = y2 - iy;
|
|
|
|
/* slope from the intersection to the miter point */
|
|
mdx = mx - ix; mdy = my - iy;
|
|
|
|
/*
|
|
* Make sure the miter point line lies between the two
|
|
* faces by comparing the slopes
|
|
*/
|
|
if (slope_compare_sgn (fdx1, fdy1, mdx, mdy) !=
|
|
slope_compare_sgn (fdx2, fdy2, mdx, mdy))
|
|
{
|
|
cairo_point_t p;
|
|
|
|
p.x = _cairo_fixed_from_double (mx);
|
|
p.y = _cairo_fixed_from_double (my);
|
|
|
|
*_cairo_contour_last_point (&outer->contour) = p;
|
|
*_cairo_contour_first_point (&outer->contour) = p;
|
|
return;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case CAIRO_LINE_JOIN_BEVEL:
|
|
break;
|
|
}
|
|
contour_add_point (stroker, outer, outpt);
|
|
}
|
|
|
|
static void
|
|
outer_join (struct stroker *stroker,
|
|
const cairo_stroke_face_t *in,
|
|
const cairo_stroke_face_t *out,
|
|
int clockwise)
|
|
{
|
|
const cairo_point_t *inpt, *outpt;
|
|
struct stroke_contour *outer;
|
|
|
|
if (in->cw.x == out->cw.x && in->cw.y == out->cw.y &&
|
|
in->ccw.x == out->ccw.x && in->ccw.y == out->ccw.y)
|
|
{
|
|
return;
|
|
}
|
|
if (clockwise) {
|
|
inpt = &in->cw;
|
|
outpt = &out->cw;
|
|
outer = &stroker->cw;
|
|
} else {
|
|
inpt = &in->ccw;
|
|
outpt = &out->ccw;
|
|
outer = &stroker->ccw;
|
|
}
|
|
|
|
switch (stroker->style.line_join) {
|
|
case CAIRO_LINE_JOIN_ROUND:
|
|
/* construct a fan around the common midpoint */
|
|
add_fan (stroker,
|
|
&in->dev_vector, &out->dev_vector, &in->point,
|
|
clockwise, outer);
|
|
break;
|
|
|
|
case CAIRO_LINE_JOIN_MITER:
|
|
default: {
|
|
/* dot product of incoming slope vector with outgoing slope vector */
|
|
double in_dot_out = in->dev_slope.x * out->dev_slope.x +
|
|
in->dev_slope.y * out->dev_slope.y;
|
|
double ml = stroker->style.miter_limit;
|
|
|
|
/* Check the miter limit -- lines meeting at an acute angle
|
|
* can generate long miters, the limit converts them to bevel
|
|
*
|
|
* Consider the miter join formed when two line segments
|
|
* meet at an angle psi:
|
|
*
|
|
* /.\
|
|
* /. .\
|
|
* /./ \.\
|
|
* /./psi\.\
|
|
*
|
|
* We can zoom in on the right half of that to see:
|
|
*
|
|
* |\
|
|
* | \ psi/2
|
|
* | \
|
|
* | \
|
|
* | \
|
|
* | \
|
|
* miter \
|
|
* length \
|
|
* | \
|
|
* | .\
|
|
* | . \
|
|
* |. line \
|
|
* \ width \
|
|
* \ \
|
|
*
|
|
*
|
|
* The right triangle in that figure, (the line-width side is
|
|
* shown faintly with three '.' characters), gives us the
|
|
* following expression relating miter length, angle and line
|
|
* width:
|
|
*
|
|
* 1 /sin (psi/2) = miter_length / line_width
|
|
*
|
|
* The right-hand side of this relationship is the same ratio
|
|
* in which the miter limit (ml) is expressed. We want to know
|
|
* when the miter length is within the miter limit. That is
|
|
* when the following condition holds:
|
|
*
|
|
* 1/sin(psi/2) <= ml
|
|
* 1 <= ml sin(psi/2)
|
|
* 1 <= ml² sin²(psi/2)
|
|
* 2 <= ml² 2 sin²(psi/2)
|
|
* 2·sin²(psi/2) = 1-cos(psi)
|
|
* 2 <= ml² (1-cos(psi))
|
|
*
|
|
* in · out = |in| |out| cos (psi)
|
|
*
|
|
* in and out are both unit vectors, so:
|
|
*
|
|
* in · out = cos (psi)
|
|
*
|
|
* 2 <= ml² (1 - in · out)
|
|
*
|
|
*/
|
|
if (2 <= ml * ml * (1 + in_dot_out)) {
|
|
double x1, y1, x2, y2;
|
|
double mx, my;
|
|
double dx1, dx2, dy1, dy2;
|
|
double ix, iy;
|
|
double fdx1, fdy1, fdx2, fdy2;
|
|
double mdx, mdy;
|
|
|
|
/*
|
|
* we've got the points already transformed to device
|
|
* space, but need to do some computation with them and
|
|
* also need to transform the slope from user space to
|
|
* device space
|
|
*/
|
|
/* outer point of incoming line face */
|
|
x1 = _cairo_fixed_to_double (inpt->x);
|
|
y1 = _cairo_fixed_to_double (inpt->y);
|
|
dx1 = in->dev_slope.x;
|
|
dy1 = in->dev_slope.y;
|
|
|
|
/* outer point of outgoing line face */
|
|
x2 = _cairo_fixed_to_double (outpt->x);
|
|
y2 = _cairo_fixed_to_double (outpt->y);
|
|
dx2 = out->dev_slope.x;
|
|
dy2 = out->dev_slope.y;
|
|
|
|
/*
|
|
* Compute the location of the outer corner of the miter.
|
|
* That's pretty easy -- just the intersection of the two
|
|
* outer edges. We've got slopes and points on each
|
|
* of those edges. Compute my directly, then compute
|
|
* mx by using the edge with the larger dy; that avoids
|
|
* dividing by values close to zero.
|
|
*/
|
|
my = (((x2 - x1) * dy1 * dy2 - y2 * dx2 * dy1 + y1 * dx1 * dy2) /
|
|
(dx1 * dy2 - dx2 * dy1));
|
|
if (fabs (dy1) >= fabs (dy2))
|
|
mx = (my - y1) * dx1 / dy1 + x1;
|
|
else
|
|
mx = (my - y2) * dx2 / dy2 + x2;
|
|
|
|
/*
|
|
* When the two outer edges are nearly parallel, slight
|
|
* perturbations in the position of the outer points of the lines
|
|
* caused by representing them in fixed point form can cause the
|
|
* intersection point of the miter to move a large amount. If
|
|
* that moves the miter intersection from between the two faces,
|
|
* then draw a bevel instead.
|
|
*/
|
|
|
|
ix = _cairo_fixed_to_double (in->point.x);
|
|
iy = _cairo_fixed_to_double (in->point.y);
|
|
|
|
/* slope of one face */
|
|
fdx1 = x1 - ix; fdy1 = y1 - iy;
|
|
|
|
/* slope of the other face */
|
|
fdx2 = x2 - ix; fdy2 = y2 - iy;
|
|
|
|
/* slope from the intersection to the miter point */
|
|
mdx = mx - ix; mdy = my - iy;
|
|
|
|
/*
|
|
* Make sure the miter point line lies between the two
|
|
* faces by comparing the slopes
|
|
*/
|
|
if (slope_compare_sgn (fdx1, fdy1, mdx, mdy) !=
|
|
slope_compare_sgn (fdx2, fdy2, mdx, mdy))
|
|
{
|
|
cairo_point_t p;
|
|
|
|
p.x = _cairo_fixed_from_double (mx);
|
|
p.y = _cairo_fixed_from_double (my);
|
|
|
|
*_cairo_contour_last_point (&outer->contour) = p;
|
|
return;
|
|
}
|
|
}
|
|
break;
|
|
}
|
|
|
|
case CAIRO_LINE_JOIN_BEVEL:
|
|
break;
|
|
}
|
|
contour_add_point (stroker,outer, outpt);
|
|
}
|
|
|
|
static void
|
|
add_cap (struct stroker *stroker,
|
|
const cairo_stroke_face_t *f,
|
|
struct stroke_contour *c)
|
|
{
|
|
switch (stroker->style.line_cap) {
|
|
case CAIRO_LINE_CAP_ROUND: {
|
|
cairo_slope_t slope;
|
|
|
|
slope.dx = -f->dev_vector.dx;
|
|
slope.dy = -f->dev_vector.dy;
|
|
|
|
add_fan (stroker, &f->dev_vector, &slope, &f->point, FALSE, c);
|
|
break;
|
|
}
|
|
|
|
case CAIRO_LINE_CAP_SQUARE: {
|
|
cairo_slope_t fvector;
|
|
cairo_point_t p;
|
|
double dx, dy;
|
|
|
|
dx = f->usr_vector.x;
|
|
dy = f->usr_vector.y;
|
|
dx *= stroker->half_line_width;
|
|
dy *= stroker->half_line_width;
|
|
cairo_matrix_transform_distance (stroker->ctm, &dx, &dy);
|
|
fvector.dx = _cairo_fixed_from_double (dx);
|
|
fvector.dy = _cairo_fixed_from_double (dy);
|
|
|
|
p.x = f->ccw.x + fvector.dx;
|
|
p.y = f->ccw.y + fvector.dy;
|
|
contour_add_point (stroker, c, &p);
|
|
|
|
p.x = f->cw.x + fvector.dx;
|
|
p.y = f->cw.y + fvector.dy;
|
|
contour_add_point (stroker, c, &p);
|
|
}
|
|
|
|
case CAIRO_LINE_CAP_BUTT:
|
|
default:
|
|
break;
|
|
}
|
|
contour_add_point (stroker, c, &f->cw);
|
|
}
|
|
|
|
static void
|
|
add_leading_cap (struct stroker *stroker,
|
|
const cairo_stroke_face_t *face,
|
|
struct stroke_contour *c)
|
|
{
|
|
cairo_stroke_face_t reversed;
|
|
cairo_point_t t;
|
|
|
|
reversed = *face;
|
|
|
|
/* The initial cap needs an outward facing vector. Reverse everything */
|
|
reversed.usr_vector.x = -reversed.usr_vector.x;
|
|
reversed.usr_vector.y = -reversed.usr_vector.y;
|
|
reversed.dev_vector.dx = -reversed.dev_vector.dx;
|
|
reversed.dev_vector.dy = -reversed.dev_vector.dy;
|
|
|
|
t = reversed.cw;
|
|
reversed.cw = reversed.ccw;
|
|
reversed.ccw = t;
|
|
|
|
add_cap (stroker, &reversed, c);
|
|
}
|
|
|
|
static void
|
|
add_trailing_cap (struct stroker *stroker,
|
|
const cairo_stroke_face_t *face,
|
|
struct stroke_contour *c)
|
|
{
|
|
add_cap (stroker, face, c);
|
|
}
|
|
|
|
static inline double
|
|
normalize_slope (double *dx, double *dy)
|
|
{
|
|
double dx0 = *dx, dy0 = *dy;
|
|
double mag;
|
|
|
|
assert (dx0 != 0.0 || dy0 != 0.0);
|
|
|
|
if (dx0 == 0.0) {
|
|
*dx = 0.0;
|
|
if (dy0 > 0.0) {
|
|
mag = dy0;
|
|
*dy = 1.0;
|
|
} else {
|
|
mag = -dy0;
|
|
*dy = -1.0;
|
|
}
|
|
} else if (dy0 == 0.0) {
|
|
*dy = 0.0;
|
|
if (dx0 > 0.0) {
|
|
mag = dx0;
|
|
*dx = 1.0;
|
|
} else {
|
|
mag = -dx0;
|
|
*dx = -1.0;
|
|
}
|
|
} else {
|
|
mag = hypot (dx0, dy0);
|
|
*dx = dx0 / mag;
|
|
*dy = dy0 / mag;
|
|
}
|
|
|
|
return mag;
|
|
}
|
|
|
|
static void
|
|
compute_face (const cairo_point_t *point,
|
|
const cairo_slope_t *dev_slope,
|
|
struct stroker *stroker,
|
|
cairo_stroke_face_t *face)
|
|
{
|
|
double face_dx, face_dy;
|
|
cairo_point_t offset_ccw, offset_cw;
|
|
double slope_dx, slope_dy;
|
|
|
|
slope_dx = _cairo_fixed_to_double (dev_slope->dx);
|
|
slope_dy = _cairo_fixed_to_double (dev_slope->dy);
|
|
face->length = normalize_slope (&slope_dx, &slope_dy);
|
|
face->dev_slope.x = slope_dx;
|
|
face->dev_slope.y = slope_dy;
|
|
|
|
/*
|
|
* rotate to get a line_width/2 vector along the face, note that
|
|
* the vector must be rotated the right direction in device space,
|
|
* but by 90° in user space. So, the rotation depends on
|
|
* whether the ctm reflects or not, and that can be determined
|
|
* by looking at the determinant of the matrix.
|
|
*/
|
|
if (! _cairo_matrix_is_identity (stroker->ctm_inverse)) {
|
|
/* Normalize the matrix! */
|
|
cairo_matrix_transform_distance (stroker->ctm_inverse,
|
|
&slope_dx, &slope_dy);
|
|
normalize_slope (&slope_dx, &slope_dy);
|
|
|
|
if (stroker->ctm_det_positive) {
|
|
face_dx = - slope_dy * stroker->half_line_width;
|
|
face_dy = slope_dx * stroker->half_line_width;
|
|
} else {
|
|
face_dx = slope_dy * stroker->half_line_width;
|
|
face_dy = - slope_dx * stroker->half_line_width;
|
|
}
|
|
|
|
/* back to device space */
|
|
cairo_matrix_transform_distance (stroker->ctm, &face_dx, &face_dy);
|
|
} else {
|
|
face_dx = - slope_dy * stroker->half_line_width;
|
|
face_dy = slope_dx * stroker->half_line_width;
|
|
}
|
|
|
|
offset_ccw.x = _cairo_fixed_from_double (face_dx);
|
|
offset_ccw.y = _cairo_fixed_from_double (face_dy);
|
|
offset_cw.x = -offset_ccw.x;
|
|
offset_cw.y = -offset_ccw.y;
|
|
|
|
face->ccw = *point;
|
|
translate_point (&face->ccw, &offset_ccw);
|
|
|
|
face->point = *point;
|
|
|
|
face->cw = *point;
|
|
translate_point (&face->cw, &offset_cw);
|
|
|
|
face->usr_vector.x = slope_dx;
|
|
face->usr_vector.y = slope_dy;
|
|
|
|
face->dev_vector = *dev_slope;
|
|
}
|
|
|
|
static void
|
|
add_caps (struct stroker *stroker)
|
|
{
|
|
/* check for a degenerative sub_path */
|
|
if (stroker->has_initial_sub_path &&
|
|
! stroker->has_first_face &&
|
|
! stroker->has_current_face &&
|
|
stroker->style.line_cap == CAIRO_LINE_CAP_ROUND)
|
|
{
|
|
/* pick an arbitrary slope to use */
|
|
cairo_slope_t slope = { CAIRO_FIXED_ONE, 0 };
|
|
cairo_stroke_face_t face;
|
|
|
|
/* arbitrarily choose first_point */
|
|
compute_face (&stroker->first_point, &slope, stroker, &face);
|
|
|
|
add_leading_cap (stroker, &face, &stroker->ccw);
|
|
add_trailing_cap (stroker, &face, &stroker->ccw);
|
|
|
|
/* ensure the circle is complete */
|
|
_cairo_contour_add_point (&stroker->ccw.contour,
|
|
_cairo_contour_first_point (&stroker->ccw.contour));
|
|
|
|
_cairo_polygon_add_contour (stroker->polygon, &stroker->ccw.contour);
|
|
_cairo_contour_reset (&stroker->ccw.contour);
|
|
} else {
|
|
if (stroker->has_current_face)
|
|
add_trailing_cap (stroker, &stroker->current_face, &stroker->ccw);
|
|
|
|
#if DEBUG
|
|
{
|
|
FILE *file = fopen ("contours.txt", "a");
|
|
_cairo_debug_print_contour (file, &stroker->path);
|
|
_cairo_debug_print_contour (file, &stroker->cw.contour);
|
|
_cairo_debug_print_contour (file, &stroker->ccw.contour);
|
|
fclose (file);
|
|
_cairo_contour_reset (&stroker->path);
|
|
}
|
|
#endif
|
|
|
|
_cairo_polygon_add_contour (stroker->polygon, &stroker->ccw.contour);
|
|
_cairo_contour_reset (&stroker->ccw.contour);
|
|
|
|
if (stroker->has_first_face) {
|
|
_cairo_contour_add_point (&stroker->ccw.contour,
|
|
&stroker->first_face.cw);
|
|
add_leading_cap (stroker, &stroker->first_face, &stroker->ccw);
|
|
#if DEBUG
|
|
{
|
|
FILE *file = fopen ("contours.txt", "a");
|
|
_cairo_debug_print_contour (file, &stroker->ccw.contour);
|
|
fclose (file);
|
|
}
|
|
#endif
|
|
|
|
_cairo_polygon_add_contour (stroker->polygon,
|
|
&stroker->ccw.contour);
|
|
_cairo_contour_reset (&stroker->ccw.contour);
|
|
}
|
|
|
|
_cairo_polygon_add_contour (stroker->polygon, &stroker->cw.contour);
|
|
_cairo_contour_reset (&stroker->cw.contour);
|
|
}
|
|
}
|
|
|
|
static cairo_status_t
|
|
close_path (void *closure);
|
|
|
|
static cairo_status_t
|
|
move_to (void *closure,
|
|
const cairo_point_t *point)
|
|
{
|
|
struct stroker *stroker = closure;
|
|
|
|
/* Cap the start and end of the previous sub path as needed */
|
|
add_caps (stroker);
|
|
|
|
stroker->has_first_face = FALSE;
|
|
stroker->has_current_face = FALSE;
|
|
stroker->has_initial_sub_path = FALSE;
|
|
|
|
stroker->first_point = *point;
|
|
|
|
#if DEBUG
|
|
_cairo_contour_add_point (&stroker->path, point);
|
|
#endif
|
|
|
|
stroker->current_face.point = *point;
|
|
|
|
return CAIRO_STATUS_SUCCESS;
|
|
}
|
|
|
|
static cairo_status_t
|
|
line_to (void *closure,
|
|
const cairo_point_t *point)
|
|
{
|
|
struct stroker *stroker = closure;
|
|
cairo_stroke_face_t start;
|
|
cairo_point_t *p1 = &stroker->current_face.point;
|
|
cairo_slope_t dev_slope;
|
|
|
|
stroker->has_initial_sub_path = TRUE;
|
|
|
|
if (p1->x == point->x && p1->y == point->y)
|
|
return CAIRO_STATUS_SUCCESS;
|
|
|
|
#if DEBUG
|
|
_cairo_contour_add_point (&stroker->path, point);
|
|
#endif
|
|
|
|
_cairo_slope_init (&dev_slope, p1, point);
|
|
compute_face (p1, &dev_slope, stroker, &start);
|
|
|
|
if (stroker->has_current_face) {
|
|
int clockwise = _cairo_slope_compare (&stroker->current_face.dev_vector,
|
|
&start.dev_vector);
|
|
if (clockwise) {
|
|
clockwise = clockwise < 0;
|
|
/* Join with final face from previous segment */
|
|
if (! within_tolerance (&stroker->current_face.ccw, &start.ccw,
|
|
stroker->contour_tolerance) ||
|
|
! within_tolerance (&stroker->current_face.cw, &start.cw,
|
|
stroker->contour_tolerance))
|
|
{
|
|
outer_join (stroker, &stroker->current_face, &start, clockwise);
|
|
inner_join (stroker, &stroker->current_face, &start, clockwise);
|
|
}
|
|
}
|
|
} else {
|
|
if (! stroker->has_first_face) {
|
|
/* Save sub path's first face in case needed for closing join */
|
|
stroker->first_face = start;
|
|
stroker->has_first_face = TRUE;
|
|
}
|
|
stroker->has_current_face = TRUE;
|
|
|
|
contour_add_point (stroker, &stroker->cw, &start.cw);
|
|
contour_add_point (stroker, &stroker->ccw, &start.ccw);
|
|
}
|
|
|
|
stroker->current_face = start;
|
|
stroker->current_face.point = *point;
|
|
stroker->current_face.ccw.x += dev_slope.dx;
|
|
stroker->current_face.ccw.y += dev_slope.dy;
|
|
stroker->current_face.cw.x += dev_slope.dx;
|
|
stroker->current_face.cw.y += dev_slope.dy;
|
|
|
|
contour_add_point (stroker, &stroker->cw, &stroker->current_face.cw);
|
|
contour_add_point (stroker, &stroker->ccw, &stroker->current_face.ccw);
|
|
|
|
return CAIRO_STATUS_SUCCESS;
|
|
}
|
|
|
|
static cairo_status_t
|
|
spline_to (void *closure,
|
|
const cairo_point_t *point,
|
|
const cairo_slope_t *tangent)
|
|
{
|
|
struct stroker *stroker = closure;
|
|
cairo_stroke_face_t face;
|
|
|
|
#if DEBUG
|
|
_cairo_contour_add_point (&stroker->path, point);
|
|
#endif
|
|
if ((tangent->dx | tangent->dy) == 0) {
|
|
const cairo_point_t *inpt, *outpt;
|
|
struct stroke_contour *outer;
|
|
cairo_point_t t;
|
|
int clockwise;
|
|
|
|
face = stroker->current_face;
|
|
|
|
face.usr_vector.x = -face.usr_vector.x;
|
|
face.usr_vector.y = -face.usr_vector.y;
|
|
face.dev_vector.dx = -face.dev_vector.dx;
|
|
face.dev_vector.dy = -face.dev_vector.dy;
|
|
|
|
t = face.cw;
|
|
face.cw = face.ccw;
|
|
face.ccw = t;
|
|
|
|
clockwise = join_is_clockwise (&stroker->current_face, &face);
|
|
if (clockwise) {
|
|
inpt = &stroker->current_face.cw;
|
|
outpt = &face.cw;
|
|
outer = &stroker->cw;
|
|
} else {
|
|
inpt = &stroker->current_face.ccw;
|
|
outpt = &face.ccw;
|
|
outer = &stroker->ccw;
|
|
}
|
|
|
|
add_fan (stroker,
|
|
&stroker->current_face.dev_vector,
|
|
&face.dev_vector,
|
|
&stroker->current_face.point,
|
|
clockwise, outer);
|
|
} else {
|
|
compute_face (point, tangent, stroker, &face);
|
|
|
|
if ((face.dev_slope.x * stroker->current_face.dev_slope.x +
|
|
face.dev_slope.y * stroker->current_face.dev_slope.y) < stroker->spline_cusp_tolerance)
|
|
{
|
|
const cairo_point_t *inpt, *outpt;
|
|
struct stroke_contour *outer;
|
|
int clockwise = join_is_clockwise (&stroker->current_face, &face);
|
|
|
|
stroker->current_face.cw.x += face.point.x - stroker->current_face.point.x;
|
|
stroker->current_face.cw.y += face.point.y - stroker->current_face.point.y;
|
|
contour_add_point (stroker, &stroker->cw, &stroker->current_face.cw);
|
|
|
|
stroker->current_face.ccw.x += face.point.x - stroker->current_face.point.x;
|
|
stroker->current_face.ccw.y += face.point.y - stroker->current_face.point.y;
|
|
contour_add_point (stroker, &stroker->ccw, &stroker->current_face.ccw);
|
|
|
|
if (clockwise) {
|
|
inpt = &stroker->current_face.cw;
|
|
outpt = &face.cw;
|
|
outer = &stroker->cw;
|
|
} else {
|
|
inpt = &stroker->current_face.ccw;
|
|
outpt = &face.ccw;
|
|
outer = &stroker->ccw;
|
|
}
|
|
add_fan (stroker,
|
|
&stroker->current_face.dev_vector,
|
|
&face.dev_vector,
|
|
&stroker->current_face.point,
|
|
clockwise, outer);
|
|
}
|
|
|
|
contour_add_point (stroker, &stroker->cw, &face.cw);
|
|
contour_add_point (stroker, &stroker->ccw, &face.ccw);
|
|
}
|
|
|
|
stroker->current_face = face;
|
|
|
|
return CAIRO_STATUS_SUCCESS;
|
|
}
|
|
|
|
static cairo_status_t
|
|
curve_to (void *closure,
|
|
const cairo_point_t *b,
|
|
const cairo_point_t *c,
|
|
const cairo_point_t *d)
|
|
{
|
|
struct stroker *stroker = closure;
|
|
cairo_spline_t spline;
|
|
cairo_stroke_face_t face;
|
|
|
|
if (stroker->has_bounds &&
|
|
! _cairo_spline_intersects (&stroker->current_face.point, b, c, d,
|
|
&stroker->bounds))
|
|
return line_to (closure, d);
|
|
|
|
if (! _cairo_spline_init (&spline, spline_to, stroker,
|
|
&stroker->current_face.point, b, c, d))
|
|
return line_to (closure, d);
|
|
|
|
compute_face (&stroker->current_face.point, &spline.initial_slope,
|
|
stroker, &face);
|
|
|
|
if (stroker->has_current_face) {
|
|
int clockwise = join_is_clockwise (&stroker->current_face, &face);
|
|
/* Join with final face from previous segment */
|
|
outer_join (stroker, &stroker->current_face, &face, clockwise);
|
|
inner_join (stroker, &stroker->current_face, &face, clockwise);
|
|
} else {
|
|
if (! stroker->has_first_face) {
|
|
/* Save sub path's first face in case needed for closing join */
|
|
stroker->first_face = face;
|
|
stroker->has_first_face = TRUE;
|
|
}
|
|
stroker->has_current_face = TRUE;
|
|
|
|
contour_add_point (stroker, &stroker->cw, &face.cw);
|
|
contour_add_point (stroker, &stroker->ccw, &face.ccw);
|
|
}
|
|
stroker->current_face = face;
|
|
|
|
return _cairo_spline_decompose (&spline, stroker->tolerance);
|
|
}
|
|
|
|
static cairo_status_t
|
|
close_path (void *closure)
|
|
{
|
|
struct stroker *stroker = closure;
|
|
cairo_status_t status;
|
|
|
|
status = line_to (stroker, &stroker->first_point);
|
|
if (unlikely (status))
|
|
return status;
|
|
|
|
if (stroker->has_first_face && stroker->has_current_face) {
|
|
/* Join first and final faces of sub path */
|
|
outer_close (stroker, &stroker->current_face, &stroker->first_face);
|
|
inner_close (stroker, &stroker->current_face, &stroker->first_face);
|
|
#if 0
|
|
*_cairo_contour_first_point (&stroker->ccw.contour) =
|
|
*_cairo_contour_last_point (&stroker->ccw.contour);
|
|
|
|
*_cairo_contour_first_point (&stroker->cw.contour) =
|
|
*_cairo_contour_last_point (&stroker->cw.contour);
|
|
#endif
|
|
|
|
_cairo_polygon_add_contour (stroker->polygon, &stroker->cw.contour);
|
|
_cairo_polygon_add_contour (stroker->polygon, &stroker->ccw.contour);
|
|
|
|
#if DEBUG
|
|
{
|
|
FILE *file = fopen ("contours.txt", "a");
|
|
_cairo_debug_print_contour (file, &stroker->path);
|
|
_cairo_debug_print_contour (file, &stroker->cw.contour);
|
|
_cairo_debug_print_contour (file, &stroker->ccw.contour);
|
|
fclose (file);
|
|
|
|
_cairo_contour_reset (&stroker->path);
|
|
}
|
|
#endif
|
|
_cairo_contour_reset (&stroker->cw.contour);
|
|
_cairo_contour_reset (&stroker->ccw.contour);
|
|
} else {
|
|
/* Cap the start and end of the sub path as needed */
|
|
add_caps (stroker);
|
|
}
|
|
|
|
stroker->has_initial_sub_path = FALSE;
|
|
stroker->has_first_face = FALSE;
|
|
stroker->has_current_face = FALSE;
|
|
|
|
return CAIRO_STATUS_SUCCESS;
|
|
}
|
|
|
|
cairo_status_t
|
|
_cairo_path_fixed_stroke_to_polygon (const cairo_path_fixed_t *path,
|
|
const cairo_stroke_style_t *style,
|
|
const cairo_matrix_t *ctm,
|
|
const cairo_matrix_t *ctm_inverse,
|
|
double tolerance,
|
|
cairo_polygon_t *polygon)
|
|
{
|
|
struct stroker stroker;
|
|
cairo_status_t status;
|
|
|
|
if (style->num_dashes) {
|
|
return _cairo_path_fixed_stroke_dashed_to_polygon (path,
|
|
style,
|
|
ctm,
|
|
ctm_inverse,
|
|
tolerance,
|
|
polygon);
|
|
}
|
|
|
|
stroker.has_bounds = polygon->num_limits;
|
|
if (stroker.has_bounds) {
|
|
/* Extend the bounds in each direction to account for the maximum area
|
|
* we might generate trapezoids, to capture line segments that are
|
|
* outside of the bounds but which might generate rendering that's
|
|
* within bounds.
|
|
*/
|
|
double dx, dy;
|
|
cairo_fixed_t fdx, fdy;
|
|
int i;
|
|
|
|
stroker.bounds = polygon->limits[0];
|
|
for (i = 1; i < polygon->num_limits; i++)
|
|
_cairo_box_add_box (&stroker.bounds, &polygon->limits[i]);
|
|
|
|
_cairo_stroke_style_max_distance_from_path (style, path, ctm, &dx, &dy);
|
|
fdx = _cairo_fixed_from_double (dx);
|
|
fdy = _cairo_fixed_from_double (dy);
|
|
|
|
stroker.bounds.p1.x -= fdx;
|
|
stroker.bounds.p2.x += fdx;
|
|
stroker.bounds.p1.y -= fdy;
|
|
stroker.bounds.p2.y += fdy;
|
|
}
|
|
|
|
stroker.style = *style;
|
|
stroker.ctm = ctm;
|
|
stroker.ctm_inverse = ctm_inverse;
|
|
stroker.tolerance = tolerance;
|
|
stroker.half_line_width = style->line_width / 2.;
|
|
/* To test whether we need to join two segments of a spline using
|
|
* a round-join or a bevel-join, we can inspect the angle between the
|
|
* two segments. If the difference between the chord distance
|
|
* (half-line-width times the cosine of the bisection angle) and the
|
|
* half-line-width itself is greater than tolerance then we need to
|
|
* inject a point.
|
|
*/
|
|
stroker.spline_cusp_tolerance = 1 - tolerance / stroker.half_line_width;
|
|
stroker.spline_cusp_tolerance *= stroker.spline_cusp_tolerance;
|
|
stroker.spline_cusp_tolerance *= 2;
|
|
stroker.spline_cusp_tolerance -= 1;
|
|
stroker.ctm_det_positive =
|
|
_cairo_matrix_compute_determinant (ctm) >= 0.0;
|
|
|
|
stroker.pen.num_vertices = 0;
|
|
if (path->has_curve_to ||
|
|
style->line_join == CAIRO_LINE_JOIN_ROUND ||
|
|
style->line_cap == CAIRO_LINE_CAP_ROUND) {
|
|
status = _cairo_pen_init (&stroker.pen,
|
|
stroker.half_line_width,
|
|
tolerance, ctm);
|
|
if (unlikely (status))
|
|
return status;
|
|
|
|
/* If the line width is so small that the pen is reduced to a
|
|
single point, then we have nothing to do. */
|
|
if (stroker.pen.num_vertices <= 1)
|
|
return CAIRO_STATUS_SUCCESS;
|
|
}
|
|
|
|
stroker.has_current_face = FALSE;
|
|
stroker.has_first_face = FALSE;
|
|
stroker.has_initial_sub_path = FALSE;
|
|
|
|
#if DEBUG
|
|
remove ("contours.txt");
|
|
remove ("polygons.txt");
|
|
_cairo_contour_init (&stroker.path, 0);
|
|
#endif
|
|
_cairo_contour_init (&stroker.cw.contour, 1);
|
|
_cairo_contour_init (&stroker.ccw.contour, -1);
|
|
tolerance *= CAIRO_FIXED_ONE;
|
|
tolerance *= tolerance;
|
|
stroker.contour_tolerance = tolerance;
|
|
stroker.polygon = polygon;
|
|
|
|
status = _cairo_path_fixed_interpret (path,
|
|
move_to,
|
|
line_to,
|
|
curve_to,
|
|
close_path,
|
|
&stroker);
|
|
/* Cap the start and end of the final sub path as needed */
|
|
if (likely (status == CAIRO_STATUS_SUCCESS))
|
|
add_caps (&stroker);
|
|
|
|
_cairo_contour_fini (&stroker.cw.contour);
|
|
_cairo_contour_fini (&stroker.ccw.contour);
|
|
if (stroker.pen.num_vertices)
|
|
_cairo_pen_fini (&stroker.pen);
|
|
|
|
#if DEBUG
|
|
{
|
|
FILE *file = fopen ("polygons.txt", "a");
|
|
_cairo_debug_print_polygon (file, polygon);
|
|
fclose (file);
|
|
}
|
|
#endif
|
|
|
|
return status;
|
|
}
|