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Diffstat (limited to 'libs/cairo-1.16.0/src/cairo-path-stroke-polygon.c')
| -rw-r--r-- | libs/cairo-1.16.0/src/cairo-path-stroke-polygon.c | 1364 |
1 files changed, 1364 insertions, 0 deletions
diff --git a/libs/cairo-1.16.0/src/cairo-path-stroke-polygon.c b/libs/cairo-1.16.0/src/cairo-path-stroke-polygon.c new file mode 100644 index 0000000..29050fa --- /dev/null +++ b/libs/cairo-1.16.0/src/cairo-path-stroke-polygon.c @@ -0,0 +1,1364 @@ +/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */ +/* cairo - a vector graphics library with display and print output + * + * Copyright © 2002 University of Southern California + * Copyright © 2011 Intel Corporation + * + * This library is free software; you can redistribute it and/or + * modify it either under the terms of the GNU Lesser General Public + * License version 2.1 as published by the Free Software Foundation + * (the "LGPL") or, at your option, under the terms of the Mozilla + * Public License Version 1.1 (the "MPL"). If you do not alter this + * notice, a recipient may use your version of this file under either + * the MPL or the LGPL. + * + * You should have received a copy of the LGPL along with this library + * in the file COPYING-LGPL-2.1; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA + * You should have received a copy of the MPL along with this library + * in the file COPYING-MPL-1.1 + * + * The contents of this file are subject to the Mozilla Public License + * Version 1.1 (the "License"); you may not use this file except in + * compliance with the License. You may obtain a copy of the License at + * http://www.mozilla.org/MPL/ + * + * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY + * OF ANY KIND, either express or implied. See the LGPL or the MPL for + * the specific language governing rights and limitations. + * + * The Original Code is the cairo graphics library. + * + * The Initial Developer of the Original Code is University of Southern + * California. + * + * Contributor(s): + * Carl D. Worth <cworth@cworth.org> + * Chris Wilson <chris@chris-wilson.co.uk> + */ + +#define _DEFAULT_SOURCE /* for hypot() */ +#include "cairoint.h" + +#include "cairo-box-inline.h" +#include "cairo-boxes-private.h" +#include "cairo-contour-inline.h" +#include "cairo-contour-private.h" +#include "cairo-error-private.h" +#include "cairo-path-fixed-private.h" +#include "cairo-slope-private.h" + +#define DEBUG 0 + +struct stroker { + cairo_stroke_style_t style; + +#if DEBUG + cairo_contour_t path; +#endif + + struct stroke_contour { + /* Note that these are not strictly contours as they may intersect */ + cairo_contour_t contour; + } cw, ccw; + cairo_uint64_t contour_tolerance; + cairo_polygon_t *polygon; + + const cairo_matrix_t *ctm; + const cairo_matrix_t *ctm_inverse; + double tolerance; + double spline_cusp_tolerance; + double half_line_width; + cairo_bool_t ctm_det_positive; + + cairo_pen_t pen; + + cairo_point_t first_point; + + cairo_bool_t has_initial_sub_path; + + cairo_bool_t has_current_face; + cairo_stroke_face_t current_face; + + cairo_bool_t has_first_face; + cairo_stroke_face_t first_face; + + cairo_bool_t has_bounds; + cairo_box_t bounds; +}; + +static inline double +normalize_slope (double *dx, double *dy); + +static void +compute_face (const cairo_point_t *point, + const cairo_slope_t *dev_slope, + struct stroker *stroker, + cairo_stroke_face_t *face); + +static cairo_uint64_t +point_distance_sq (const cairo_point_t *p1, + const cairo_point_t *p2) +{ + int32_t dx = p1->x - p2->x; + int32_t dy = p1->y - p2->y; + return _cairo_int32x32_64_mul (dx, dx) + _cairo_int32x32_64_mul (dy, dy); +} + +static cairo_bool_t +within_tolerance (const cairo_point_t *p1, + const cairo_point_t *p2, + cairo_uint64_t tolerance) +{ + return FALSE; + return _cairo_int64_lt (point_distance_sq (p1, p2), tolerance); +} + +static void +contour_add_point (struct stroker *stroker, + struct stroke_contour *c, + const cairo_point_t *point) +{ + if (! within_tolerance (point, _cairo_contour_last_point (&c->contour), + stroker->contour_tolerance)) + _cairo_contour_add_point (&c->contour, point); + //*_cairo_contour_last_point (&c->contour) = *point; +} + +static void +translate_point (cairo_point_t *point, const cairo_point_t *offset) +{ + point->x += offset->x; + point->y += offset->y; +} + +static int +slope_compare_sgn (double dx1, double dy1, double dx2, double dy2) +{ + double c = (dx1 * dy2 - dx2 * dy1); + + if (c > 0) return 1; + if (c < 0) return -1; + return 0; +} + +static inline int +range_step (int i, int step, int max) +{ + i += step; + if (i < 0) + i = max - 1; + if (i >= max) + i = 0; + return i; +} + +/* + * Construct a fan around the midpoint using the vertices from pen between + * inpt and outpt. + */ +static void +add_fan (struct stroker *stroker, + const cairo_slope_t *in_vector, + const cairo_slope_t *out_vector, + const cairo_point_t *midpt, + cairo_bool_t clockwise, + struct stroke_contour *c) +{ + cairo_pen_t *pen = &stroker->pen; + int start, stop; + + if (stroker->has_bounds && + ! _cairo_box_contains_point (&stroker->bounds, midpt)) + return; + + assert (stroker->pen.num_vertices); + + if (clockwise) { + _cairo_pen_find_active_cw_vertices (pen, + in_vector, out_vector, + &start, &stop); + while (start != stop) { + cairo_point_t p = *midpt; + translate_point (&p, &pen->vertices[start].point); + contour_add_point (stroker, c, &p); + + if (++start == pen->num_vertices) + start = 0; + } + } else { + _cairo_pen_find_active_ccw_vertices (pen, + in_vector, out_vector, + &start, &stop); + while (start != stop) { + cairo_point_t p = *midpt; + translate_point (&p, &pen->vertices[start].point); + contour_add_point (stroker, c, &p); + + if (start-- == 0) + start += pen->num_vertices; + } + } +} + +static int +join_is_clockwise (const cairo_stroke_face_t *in, + const cairo_stroke_face_t *out) +{ + return _cairo_slope_compare (&in->dev_vector, &out->dev_vector) < 0; +} + +static void +inner_join (struct stroker *stroker, + const cairo_stroke_face_t *in, + const cairo_stroke_face_t *out, + int clockwise) +{ +#if 0 + cairo_point_t last; + const cairo_point_t *p, *outpt; + struct stroke_contour *inner; + cairo_int64_t d_p, d_last; + cairo_int64_t half_line_width; + cairo_bool_t negate; + + /* XXX line segments shorter than line-width */ + + if (clockwise) { + inner = &stroker->ccw; + outpt = &out->ccw; + negate = 1; + } else { + inner = &stroker->cw; + outpt = &out->cw; + negate = 0; + } + + half_line_width = CAIRO_FIXED_ONE*CAIRO_FIXED_ONE/2 * stroker->style.line_width * out->length + .5; + + /* On the inside, the previous end-point is always + * closer to the new face by definition. + */ + last = *_cairo_contour_last_point (&inner->contour); + d_last = distance_from_face (out, &last, negate); + _cairo_contour_remove_last_point (&inner->contour); + +prev: + if (inner->contour.chain.num_points == 0) { + contour_add_point (stroker, inner, outpt); + return; + } + p = _cairo_contour_last_point (&inner->contour); + d_p = distance_from_face (out, p, negate); + if (_cairo_int64_lt (d_p, half_line_width) && + !_cairo_int64_negative (distance_along_face (out, p))) + { + last = *p; + d_last = d_p; + _cairo_contour_remove_last_point (&inner->contour); + goto prev; + } + + compute_inner_joint (&last, d_last, p, d_p, half_line_width); + contour_add_point (stroker, inner, &last); +#else + const cairo_point_t *outpt; + struct stroke_contour *inner; + + if (clockwise) { + inner = &stroker->ccw; + outpt = &out->ccw; + } else { + inner = &stroker->cw; + outpt = &out->cw; + } + contour_add_point (stroker, inner, &in->point); + contour_add_point (stroker, inner, outpt); +#endif +} + +static void +inner_close (struct stroker *stroker, + const cairo_stroke_face_t *in, + cairo_stroke_face_t *out) +{ +#if 0 + cairo_point_t last; + const cairo_point_t *p, *outpt, *inpt; + struct stroke_contour *inner; + struct _cairo_contour_chain *chain; + + /* XXX line segments shorter than line-width */ + + if (join_is_clockwise (in, out)) { + inner = &stroker->ccw; + outpt = &in->ccw; + inpt = &out->ccw; + } else { + inner = &stroker->cw; + outpt = &in->cw; + inpt = &out->cw; + } + + if (inner->contour.chain.num_points == 0) { + contour_add_point (stroker, inner, &in->point); + contour_add_point (stroker, inner, inpt); + *_cairo_contour_first_point (&inner->contour) = + *_cairo_contour_last_point (&inner->contour); + return; + } + + line_width = stroker->style.line_width/2; + line_width *= CAIRO_FIXED_ONE; + + d_last = sign * distance_from_face (out, outpt); + last = *outpt; + + for (chain = &inner->contour.chain; chain; chain = chain->next) { + for (i = 0; i < chain->num_points; i++) { + p = &chain->points[i]; + if ((d_p = sign * distance_from_face (in, p)) >= line_width && + distance_from_edge (stroker, inpt, &last, p) < line_width) + { + goto out; + } + + if (p->x != last.x || p->y != last.y) { + last = *p; + d_last = d_p; + } + } + } +out: + + if (d_p != d_last) { + double dot = (line_width - d_last) / (d_p - d_last); + last.x += dot * (p->x - last.x); + last.y += dot * (p->y - last.y); + } + *_cairo_contour_last_point (&inner->contour) = last; + + for (chain = &inner->contour.chain; chain; chain = chain->next) { + for (i = 0; i < chain->num_points; i++) { + cairo_point_t *pp = &chain->points[i]; + if (pp == p) + return; + *pp = last; + } + } +#else + const cairo_point_t *inpt; + struct stroke_contour *inner; + + if (join_is_clockwise (in, out)) { + inner = &stroker->ccw; + inpt = &out->ccw; + } else { + inner = &stroker->cw; + inpt = &out->cw; + } + + contour_add_point (stroker, inner, &in->point); + contour_add_point (stroker, inner, inpt); + *_cairo_contour_first_point (&inner->contour) = + *_cairo_contour_last_point (&inner->contour); +#endif +} + +static void +outer_close (struct stroker *stroker, + const cairo_stroke_face_t *in, + const cairo_stroke_face_t *out) +{ + const cairo_point_t *inpt, *outpt; + struct stroke_contour *outer; + int clockwise; + + 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; + } + + clockwise = join_is_clockwise (in, out); + if (clockwise) { + inpt = &in->cw; + outpt = &out->cw; + outer = &stroker->cw; + } else { + inpt = &in->ccw; + outpt = &out->ccw; + outer = &stroker->ccw; + } + + if (within_tolerance (inpt, outpt, stroker->contour_tolerance)) { + *_cairo_contour_first_point (&outer->contour) = + *_cairo_contour_last_point (&outer->contour); + return; + } + + switch (stroker->style.line_join) { + case CAIRO_LINE_JOIN_ROUND: + /* construct a fan around the common midpoint */ + if ((in->dev_slope.x * out->dev_slope.x + + in->dev_slope.y * out->dev_slope.y) < stroker->spline_cusp_tolerance) + { + 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; + *_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) { + 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) { + outer = &stroker->cw; + } else { + 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) + { + 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) { + outer = &stroker->cw; + } else { + 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; +} |