diff options
Diffstat (limited to 'libs/cairo-1.16.0/src/cairo-path-stroke.c')
| -rw-r--r-- | libs/cairo-1.16.0/src/cairo-path-stroke.c | 1485 |
1 files changed, 1485 insertions, 0 deletions
diff --git a/libs/cairo-1.16.0/src/cairo-path-stroke.c b/libs/cairo-1.16.0/src/cairo-path-stroke.c new file mode 100644 index 0000000..64cec8f --- /dev/null +++ b/libs/cairo-1.16.0/src/cairo-path-stroke.c @@ -0,0 +1,1485 @@ +/* -*- 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 + * + * 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-error-private.h" +#include "cairo-path-fixed-private.h" +#include "cairo-slope-private.h" +#include "cairo-stroke-dash-private.h" +#include "cairo-traps-private.h" + +typedef struct cairo_stroker { + cairo_stroke_style_t style; + + const cairo_matrix_t *ctm; + const cairo_matrix_t *ctm_inverse; + double half_line_width; + double tolerance; + double spline_cusp_tolerance; + double ctm_determinant; + cairo_bool_t ctm_det_positive; + + void *closure; + cairo_status_t (*add_external_edge) (void *closure, + const cairo_point_t *p1, + const cairo_point_t *p2); + cairo_status_t (*add_triangle) (void *closure, + const cairo_point_t triangle[3]); + cairo_status_t (*add_triangle_fan) (void *closure, + const cairo_point_t *midpt, + const cairo_point_t *points, + int npoints); + cairo_status_t (*add_convex_quad) (void *closure, + const cairo_point_t quad[4]); + + cairo_pen_t pen; + + cairo_point_t current_point; + 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_stroker_dash_t dash; + + cairo_bool_t has_bounds; + cairo_box_t bounds; +} cairo_stroker_t; + +static void +_cairo_stroker_limit (cairo_stroker_t *stroker, + const cairo_path_fixed_t *path, + const cairo_box_t *boxes, + int num_boxes) +{ + double dx, dy; + cairo_fixed_t fdx, fdy; + + stroker->has_bounds = TRUE; + _cairo_boxes_get_extents (boxes, num_boxes, &stroker->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. + */ + + _cairo_stroke_style_max_distance_from_path (&stroker->style, path, + stroker->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; +} + +static cairo_status_t +_cairo_stroker_init (cairo_stroker_t *stroker, + const cairo_path_fixed_t *path, + const cairo_stroke_style_t *stroke_style, + const cairo_matrix_t *ctm, + const cairo_matrix_t *ctm_inverse, + double tolerance, + const cairo_box_t *limits, + int num_limits) +{ + cairo_status_t status; + + stroker->style = *stroke_style; + stroker->ctm = ctm; + stroker->ctm_inverse = ctm_inverse; + stroker->tolerance = tolerance; + stroker->half_line_width = stroke_style->line_width / 2.0; + + /* 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_determinant = _cairo_matrix_compute_determinant (stroker->ctm); + stroker->ctm_det_positive = stroker->ctm_determinant >= 0.0; + + status = _cairo_pen_init (&stroker->pen, + stroker->half_line_width, tolerance, ctm); + if (unlikely (status)) + return status; + + stroker->has_current_face = FALSE; + stroker->has_first_face = FALSE; + stroker->has_initial_sub_path = FALSE; + + _cairo_stroker_dash_init (&stroker->dash, stroke_style); + + stroker->add_external_edge = NULL; + + stroker->has_bounds = FALSE; + if (num_limits) + _cairo_stroker_limit (stroker, path, limits, num_limits); + + return CAIRO_STATUS_SUCCESS; +} + +static void +_cairo_stroker_fini (cairo_stroker_t *stroker) +{ + _cairo_pen_fini (&stroker->pen); +} + +static void +_translate_point (cairo_point_t *point, const cairo_point_t *offset) +{ + point->x += offset->x; + point->y += offset->y; +} + +static int +_cairo_stroker_join_is_clockwise (const cairo_stroke_face_t *in, + const cairo_stroke_face_t *out) +{ + cairo_slope_t in_slope, out_slope; + + _cairo_slope_init (&in_slope, &in->point, &in->cw); + _cairo_slope_init (&out_slope, &out->point, &out->cw); + + return _cairo_slope_compare (&in_slope, &out_slope) < 0; +} + +/** + * _cairo_slope_compare_sgn: + * + * Return -1, 0 or 1 depending on the relative slopes of + * two lines. + **/ +static int +_cairo_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 cairo_status_t +_tessellate_fan (cairo_stroker_t *stroker, + const cairo_slope_t *in_vector, + const cairo_slope_t *out_vector, + const cairo_point_t *midpt, + const cairo_point_t *inpt, + const cairo_point_t *outpt, + cairo_bool_t clockwise) +{ + cairo_point_t stack_points[64], *points = stack_points; + cairo_pen_t *pen = &stroker->pen; + int start, stop, num_points = 0; + cairo_status_t status; + + if (stroker->has_bounds && + ! _cairo_box_contains_point (&stroker->bounds, midpt)) + goto BEVEL; + + assert (stroker->pen.num_vertices); + + if (clockwise) { + _cairo_pen_find_active_ccw_vertices (pen, + in_vector, out_vector, + &start, &stop); + if (stroker->add_external_edge) { + cairo_point_t last; + last = *inpt; + while (start != stop) { + cairo_point_t p = *midpt; + _translate_point (&p, &pen->vertices[start].point); + + status = stroker->add_external_edge (stroker->closure, + &last, &p); + if (unlikely (status)) + return status; + last = p; + + if (start-- == 0) + start += pen->num_vertices; + } + status = stroker->add_external_edge (stroker->closure, + &last, outpt); + } else { + if (start == stop) + goto BEVEL; + + num_points = stop - start; + if (num_points < 0) + num_points += pen->num_vertices; + num_points += 2; + if (num_points > ARRAY_LENGTH(stack_points)) { + points = _cairo_malloc_ab (num_points, sizeof (cairo_point_t)); + if (unlikely (points == NULL)) + return _cairo_error (CAIRO_STATUS_NO_MEMORY); + } + + points[0] = *inpt; + num_points = 1; + while (start != stop) { + points[num_points] = *midpt; + _translate_point (&points[num_points], &pen->vertices[start].point); + num_points++; + + if (start-- == 0) + start += pen->num_vertices; + } + points[num_points++] = *outpt; + } + } else { + _cairo_pen_find_active_cw_vertices (pen, + in_vector, out_vector, + &start, &stop); + if (stroker->add_external_edge) { + cairo_point_t last; + last = *inpt; + while (start != stop) { + cairo_point_t p = *midpt; + _translate_point (&p, &pen->vertices[start].point); + + status = stroker->add_external_edge (stroker->closure, + &p, &last); + if (unlikely (status)) + return status; + last = p; + + if (++start == pen->num_vertices) + start = 0; + } + status = stroker->add_external_edge (stroker->closure, + outpt, &last); + } else { + if (start == stop) + goto BEVEL; + + num_points = stop - start; + if (num_points < 0) + num_points += pen->num_vertices; + num_points += 2; + if (num_points > ARRAY_LENGTH(stack_points)) { + points = _cairo_malloc_ab (num_points, sizeof (cairo_point_t)); + if (unlikely (points == NULL)) + return _cairo_error (CAIRO_STATUS_NO_MEMORY); + } + + points[0] = *inpt; + num_points = 1; + while (start != stop) { + points[num_points] = *midpt; + _translate_point (&points[num_points], &pen->vertices[start].point); + num_points++; + + if (++start == pen->num_vertices) + start = 0; + } + points[num_points++] = *outpt; + } + } + + if (num_points) { + status = stroker->add_triangle_fan (stroker->closure, + midpt, points, num_points); + } + + if (points != stack_points) + free (points); + + return status; + +BEVEL: + /* Ensure a leak free connection... */ + if (stroker->add_external_edge != NULL) { + if (clockwise) + return stroker->add_external_edge (stroker->closure, inpt, outpt); + else + return stroker->add_external_edge (stroker->closure, outpt, inpt); + } else { + stack_points[0] = *midpt; + stack_points[1] = *inpt; + stack_points[2] = *outpt; + return stroker->add_triangle (stroker->closure, stack_points); + } +} + +static cairo_status_t +_cairo_stroker_join (cairo_stroker_t *stroker, + const cairo_stroke_face_t *in, + const cairo_stroke_face_t *out) +{ + int clockwise = _cairo_stroker_join_is_clockwise (out, in); + const cairo_point_t *inpt, *outpt; + cairo_point_t points[4]; + cairo_status_t status; + + 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 CAIRO_STATUS_SUCCESS; + } + + if (clockwise) { + if (stroker->add_external_edge != NULL) { + status = stroker->add_external_edge (stroker->closure, + &out->cw, &in->point); + if (unlikely (status)) + return status; + + status = stroker->add_external_edge (stroker->closure, + &in->point, &in->cw); + if (unlikely (status)) + return status; + } + + inpt = &in->ccw; + outpt = &out->ccw; + } else { + if (stroker->add_external_edge != NULL) { + status = stroker->add_external_edge (stroker->closure, + &in->ccw, &in->point); + if (unlikely (status)) + return status; + + status = stroker->add_external_edge (stroker->closure, + &in->point, &out->ccw); + if (unlikely (status)) + return status; + } + + inpt = &in->cw; + outpt = &out->cw; + } + + switch (stroker->style.line_join) { + case CAIRO_LINE_JOIN_ROUND: + /* construct a fan around the common midpoint */ + return _tessellate_fan (stroker, + &in->dev_vector, + &out->dev_vector, + &in->point, inpt, outpt, + clockwise); + + case CAIRO_LINE_JOIN_MITER: + default: { + /* dot product of incoming slope vector with outgoing slope vector */ + double in_dot_out = -in->usr_vector.x * out->usr_vector.x + + -in->usr_vector.y * out->usr_vector.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->usr_vector.x; + dy1 = in->usr_vector.y; + cairo_matrix_transform_distance (stroker->ctm, &dx1, &dy1); + + /* outer point of outgoing line face */ + x2 = _cairo_fixed_to_double (outpt->x); + y2 = _cairo_fixed_to_double (outpt->y); + dx2 = out->usr_vector.x; + dy2 = out->usr_vector.y; + cairo_matrix_transform_distance (stroker->ctm, &dx2, &dy2); + + /* + * 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 (_cairo_slope_compare_sgn (fdx1, fdy1, mdx, mdy) != + _cairo_slope_compare_sgn (fdx2, fdy2, mdx, mdy)) + { + if (stroker->add_external_edge != NULL) { + points[0].x = _cairo_fixed_from_double (mx); + points[0].y = _cairo_fixed_from_double (my); + + if (clockwise) { + status = stroker->add_external_edge (stroker->closure, + inpt, &points[0]); + if (unlikely (status)) + return status; + + status = stroker->add_external_edge (stroker->closure, + &points[0], outpt); + if (unlikely (status)) + return status; + } else { + status = stroker->add_external_edge (stroker->closure, + outpt, &points[0]); + if (unlikely (status)) + return status; + + status = stroker->add_external_edge (stroker->closure, + &points[0], inpt); + if (unlikely (status)) + return status; + } + + return CAIRO_STATUS_SUCCESS; + } else { + points[0] = in->point; + points[1] = *inpt; + points[2].x = _cairo_fixed_from_double (mx); + points[2].y = _cairo_fixed_from_double (my); + points[3] = *outpt; + + return stroker->add_convex_quad (stroker->closure, points); + } + } + } + } + + /* fall through ... */ + + case CAIRO_LINE_JOIN_BEVEL: + if (stroker->add_external_edge != NULL) { + if (clockwise) { + return stroker->add_external_edge (stroker->closure, + inpt, outpt); + } else { + return stroker->add_external_edge (stroker->closure, + outpt, inpt); + } + } else { + points[0] = in->point; + points[1] = *inpt; + points[2] = *outpt; + + return stroker->add_triangle (stroker->closure, points); + } + } +} + +static cairo_status_t +_cairo_stroker_add_cap (cairo_stroker_t *stroker, + const cairo_stroke_face_t *f) +{ + 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; + + return _tessellate_fan (stroker, + &f->dev_vector, + &slope, + &f->point, &f->cw, &f->ccw, + FALSE); + + } + + case CAIRO_LINE_CAP_SQUARE: { + double dx, dy; + cairo_slope_t fvector; + cairo_point_t quad[4]; + + 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); + + quad[0] = f->ccw; + quad[1].x = f->ccw.x + fvector.dx; + quad[1].y = f->ccw.y + fvector.dy; + quad[2].x = f->cw.x + fvector.dx; + quad[2].y = f->cw.y + fvector.dy; + quad[3] = f->cw; + + if (stroker->add_external_edge != NULL) { + cairo_status_t status; + + status = stroker->add_external_edge (stroker->closure, + &quad[0], &quad[1]); + if (unlikely (status)) + return status; + + status = stroker->add_external_edge (stroker->closure, + &quad[1], &quad[2]); + if (unlikely (status)) + return status; + + status = stroker->add_external_edge (stroker->closure, + &quad[2], &quad[3]); + if (unlikely (status)) + return status; + + return CAIRO_STATUS_SUCCESS; + } else { + return stroker->add_convex_quad (stroker->closure, quad); + } + } + + case CAIRO_LINE_CAP_BUTT: + default: + if (stroker->add_external_edge != NULL) { + return stroker->add_external_edge (stroker->closure, + &f->ccw, &f->cw); + } else { + return CAIRO_STATUS_SUCCESS; + } + } +} + +static cairo_status_t +_cairo_stroker_add_leading_cap (cairo_stroker_t *stroker, + const cairo_stroke_face_t *face) +{ + 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; + + return _cairo_stroker_add_cap (stroker, &reversed); +} + +static cairo_status_t +_cairo_stroker_add_trailing_cap (cairo_stroker_t *stroker, + const cairo_stroke_face_t *face) +{ + return _cairo_stroker_add_cap (stroker, face); +} + +static inline cairo_bool_t +_compute_normalized_device_slope (double *dx, double *dy, + const cairo_matrix_t *ctm_inverse, + double *mag_out) +{ + double dx0 = *dx, dy0 = *dy; + double mag; + + cairo_matrix_transform_distance (ctm_inverse, &dx0, &dy0); + + if (dx0 == 0.0 && dy0 == 0.0) { + if (mag_out) + *mag_out = 0.0; + return FALSE; + } + + 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; + } + + if (mag_out) + *mag_out = mag; + + return TRUE; +} + +static void +_compute_face (const cairo_point_t *point, + const cairo_slope_t *dev_slope, + double slope_dx, + double slope_dy, + cairo_stroker_t *stroker, + cairo_stroke_face_t *face) +{ + double face_dx, face_dy; + cairo_point_t offset_ccw, offset_cw; + + /* + * 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 (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); + + 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 cairo_status_t +_cairo_stroker_add_caps (cairo_stroker_t *stroker) +{ + cairo_status_t status; + + /* 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 */ + double dx = 1.0, dy = 0.0; + cairo_slope_t slope = { CAIRO_FIXED_ONE, 0 }; + cairo_stroke_face_t face; + + _compute_normalized_device_slope (&dx, &dy, + stroker->ctm_inverse, NULL); + + /* arbitrarily choose first_point + * first_point and current_point should be the same */ + _compute_face (&stroker->first_point, &slope, dx, dy, stroker, &face); + + status = _cairo_stroker_add_leading_cap (stroker, &face); + if (unlikely (status)) + return status; + + status = _cairo_stroker_add_trailing_cap (stroker, &face); + if (unlikely (status)) + return status; + } + + if (stroker->has_first_face) { + status = _cairo_stroker_add_leading_cap (stroker, + &stroker->first_face); + if (unlikely (status)) + return status; + } + + if (stroker->has_current_face) { + status = _cairo_stroker_add_trailing_cap (stroker, + &stroker->current_face); + if (unlikely (status)) + return status; + } + + return CAIRO_STATUS_SUCCESS; +} + +static cairo_status_t +_cairo_stroker_add_sub_edge (cairo_stroker_t *stroker, + const cairo_point_t *p1, + const cairo_point_t *p2, + cairo_slope_t *dev_slope, + double slope_dx, double slope_dy, + cairo_stroke_face_t *start, + cairo_stroke_face_t *end) +{ + _compute_face (p1, dev_slope, slope_dx, slope_dy, stroker, start); + *end = *start; + + if (p1->x == p2->x && p1->y == p2->y) + return CAIRO_STATUS_SUCCESS; + + end->point = *p2; + end->ccw.x += p2->x - p1->x; + end->ccw.y += p2->y - p1->y; + end->cw.x += p2->x - p1->x; + end->cw.y += p2->y - p1->y; + + if (stroker->add_external_edge != NULL) { + cairo_status_t status; + + status = stroker->add_external_edge (stroker->closure, + &end->cw, &start->cw); + if (unlikely (status)) + return status; + + status = stroker->add_external_edge (stroker->closure, + &start->ccw, &end->ccw); + if (unlikely (status)) + return status; + + return CAIRO_STATUS_SUCCESS; + } else { + cairo_point_t quad[4]; + + quad[0] = start->cw; + quad[1] = end->cw; + quad[2] = end->ccw; + quad[3] = start->ccw; + + return stroker->add_convex_quad (stroker->closure, quad); + } +} + +static cairo_status_t +_cairo_stroker_move_to (void *closure, + const cairo_point_t *point) +{ + cairo_stroker_t *stroker = closure; + cairo_status_t status; + + /* reset the dash pattern for new sub paths */ + _cairo_stroker_dash_start (&stroker->dash); + + /* Cap the start and end of the previous sub path as needed */ + status = _cairo_stroker_add_caps (stroker); + if (unlikely (status)) + return status; + + stroker->first_point = *point; + stroker->current_point = *point; + + stroker->has_first_face = FALSE; + stroker->has_current_face = FALSE; + stroker->has_initial_sub_path = FALSE; + + return CAIRO_STATUS_SUCCESS; +} + +static cairo_status_t +_cairo_stroker_line_to (void *closure, + const cairo_point_t *point) +{ + cairo_stroker_t *stroker = closure; + cairo_stroke_face_t start, end; + cairo_point_t *p1 = &stroker->current_point; + cairo_slope_t dev_slope; + double slope_dx, slope_dy; + cairo_status_t status; + + stroker->has_initial_sub_path = TRUE; + + if (p1->x == point->x && p1->y == point->y) + return CAIRO_STATUS_SUCCESS; + + _cairo_slope_init (&dev_slope, p1, point); + slope_dx = _cairo_fixed_to_double (point->x - p1->x); + slope_dy = _cairo_fixed_to_double (point->y - p1->y); + _compute_normalized_device_slope (&slope_dx, &slope_dy, + stroker->ctm_inverse, NULL); + + status = _cairo_stroker_add_sub_edge (stroker, + p1, point, + &dev_slope, + slope_dx, slope_dy, + &start, &end); + if (unlikely (status)) + return status; + + if (stroker->has_current_face) { + /* Join with final face from previous segment */ + status = _cairo_stroker_join (stroker, + &stroker->current_face, + &start); + if (unlikely (status)) + return status; + } 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->current_face = end; + stroker->has_current_face = TRUE; + + stroker->current_point = *point; + + return CAIRO_STATUS_SUCCESS; +} + +static cairo_status_t +_cairo_stroker_spline_to (void *closure, + const cairo_point_t *point, + const cairo_slope_t *tangent) +{ + cairo_stroker_t *stroker = closure; + cairo_stroke_face_t new_face; + double slope_dx, slope_dy; + cairo_point_t points[3]; + cairo_point_t intersect_point; + + stroker->has_initial_sub_path = TRUE; + + if (stroker->current_point.x == point->x && + stroker->current_point.y == point->y) + return CAIRO_STATUS_SUCCESS; + + slope_dx = _cairo_fixed_to_double (tangent->dx); + slope_dy = _cairo_fixed_to_double (tangent->dy); + + if (! _compute_normalized_device_slope (&slope_dx, &slope_dy, + stroker->ctm_inverse, NULL)) + return CAIRO_STATUS_SUCCESS; + + _compute_face (point, tangent, + slope_dx, slope_dy, + stroker, &new_face); + + assert (stroker->has_current_face); + + if ((new_face.dev_slope.x * stroker->current_face.dev_slope.x + + new_face.dev_slope.y * stroker->current_face.dev_slope.y) < stroker->spline_cusp_tolerance) { + + const cairo_point_t *inpt, *outpt; + int clockwise = _cairo_stroker_join_is_clockwise (&new_face, + &stroker->current_face); + + if (clockwise) { + inpt = &stroker->current_face.cw; + outpt = &new_face.cw; + } else { + inpt = &stroker->current_face.ccw; + outpt = &new_face.ccw; + } + + _tessellate_fan (stroker, + &stroker->current_face.dev_vector, + &new_face.dev_vector, + &stroker->current_face.point, + inpt, outpt, + clockwise); + } + + if (_slow_segment_intersection (&stroker->current_face.cw, + &stroker->current_face.ccw, + &new_face.cw, + &new_face.ccw, + &intersect_point)) { + points[0] = stroker->current_face.ccw; + points[1] = new_face.ccw; + points[2] = intersect_point; + stroker->add_triangle (stroker->closure, points); + + points[0] = stroker->current_face.cw; + points[1] = new_face.cw; + stroker->add_triangle (stroker->closure, points); + } else { + points[0] = stroker->current_face.ccw; + points[1] = stroker->current_face.cw; + points[2] = new_face.cw; + stroker->add_triangle (stroker->closure, points); + + points[0] = stroker->current_face.ccw; + points[1] = new_face.cw; + points[2] = new_face.ccw; + stroker->add_triangle (stroker->closure, points); + } + + stroker->current_face = new_face; + stroker->has_current_face = TRUE; + stroker->current_point = *point; + + return CAIRO_STATUS_SUCCESS; +} + +/* + * Dashed lines. Cap each dash end, join around turns when on + */ +static cairo_status_t +_cairo_stroker_line_to_dashed (void *closure, + const cairo_point_t *p2) +{ + cairo_stroker_t *stroker = closure; + double mag, remain, step_length = 0; + double slope_dx, slope_dy; + double dx2, dy2; + cairo_stroke_face_t sub_start, sub_end; + cairo_point_t *p1 = &stroker->current_point; + cairo_slope_t dev_slope; + cairo_line_t segment; + cairo_bool_t fully_in_bounds; + cairo_status_t status; + + stroker->has_initial_sub_path = stroker->dash.dash_starts_on; + + if (p1->x == p2->x && p1->y == p2->y) + return CAIRO_STATUS_SUCCESS; + + fully_in_bounds = TRUE; + if (stroker->has_bounds && + (! _cairo_box_contains_point (&stroker->bounds, p1) || + ! _cairo_box_contains_point (&stroker->bounds, p2))) + { + fully_in_bounds = FALSE; + } + + _cairo_slope_init (&dev_slope, p1, p2); + + slope_dx = _cairo_fixed_to_double (p2->x - p1->x); + slope_dy = _cairo_fixed_to_double (p2->y - p1->y); + + if (! _compute_normalized_device_slope (&slope_dx, &slope_dy, + stroker->ctm_inverse, &mag)) + { + return CAIRO_STATUS_SUCCESS; + } + + remain = mag; + segment.p1 = *p1; + while (remain) { + step_length = MIN (stroker->dash.dash_remain, remain); + remain -= step_length; + dx2 = slope_dx * (mag - remain); + dy2 = slope_dy * (mag - remain); + cairo_matrix_transform_distance (stroker->ctm, &dx2, &dy2); + segment.p2.x = _cairo_fixed_from_double (dx2) + p1->x; + segment.p2.y = _cairo_fixed_from_double (dy2) + p1->y; + + if (stroker->dash.dash_on && + (fully_in_bounds || + (! stroker->has_first_face && stroker->dash.dash_starts_on) || + _cairo_box_intersects_line_segment (&stroker->bounds, &segment))) + { + status = _cairo_stroker_add_sub_edge (stroker, + &segment.p1, &segment.p2, + &dev_slope, + slope_dx, slope_dy, + &sub_start, &sub_end); + if (unlikely (status)) + return status; + + if (stroker->has_current_face) + { + /* Join with final face from previous segment */ + status = _cairo_stroker_join (stroker, + &stroker->current_face, + &sub_start); + if (unlikely (status)) + return status; + + stroker->has_current_face = FALSE; + } + else if (! stroker->has_first_face && + stroker->dash.dash_starts_on) + { + /* Save sub path's first face in case needed for closing join */ + stroker->first_face = sub_start; + stroker->has_first_face = TRUE; + } + else + { + /* Cap dash start if not connecting to a previous segment */ + status = _cairo_stroker_add_leading_cap (stroker, &sub_start); + if (unlikely (status)) + return status; + } + + if (remain) { + /* Cap dash end if not at end of segment */ + status = _cairo_stroker_add_trailing_cap (stroker, &sub_end); + if (unlikely (status)) + return status; + } else { + stroker->current_face = sub_end; + stroker->has_current_face = TRUE; + } + } else { + if (stroker->has_current_face) { + /* Cap final face from previous segment */ + status = _cairo_stroker_add_trailing_cap (stroker, + &stroker->current_face); + if (unlikely (status)) + return status; + + stroker->has_current_face = FALSE; + } + } + + _cairo_stroker_dash_step (&stroker->dash, step_length); + segment.p1 = segment.p2; + } + + if (stroker->dash.dash_on && ! stroker->has_current_face) { + /* This segment ends on a transition to dash_on, compute a new face + * and add cap for the beginning of the next dash_on step. + * + * Note: this will create a degenerate cap if this is not the last line + * in the path. Whether this behaviour is desirable or not is debatable. + * On one side these degenerate caps can not be reproduced with regular + * path stroking. + * On the other hand, Acroread 7 also produces the degenerate caps. + */ + _compute_face (p2, &dev_slope, + slope_dx, slope_dy, + stroker, + &stroker->current_face); + + status = _cairo_stroker_add_leading_cap (stroker, + &stroker->current_face); + if (unlikely (status)) + return status; + + stroker->has_current_face = TRUE; + } + + stroker->current_point = *p2; + + return CAIRO_STATUS_SUCCESS; +} + +static cairo_status_t +_cairo_stroker_curve_to (void *closure, + const cairo_point_t *b, + const cairo_point_t *c, + const cairo_point_t *d) +{ + cairo_stroker_t *stroker = closure; + cairo_spline_t spline; + cairo_line_join_t line_join_save; + cairo_stroke_face_t face; + double slope_dx, slope_dy; + cairo_spline_add_point_func_t line_to; + cairo_spline_add_point_func_t spline_to; + cairo_status_t status = CAIRO_STATUS_SUCCESS; + + line_to = stroker->dash.dashed ? + (cairo_spline_add_point_func_t) _cairo_stroker_line_to_dashed : + (cairo_spline_add_point_func_t) _cairo_stroker_line_to; + + /* spline_to is only capable of rendering non-degenerate splines. */ + spline_to = stroker->dash.dashed ? + (cairo_spline_add_point_func_t) _cairo_stroker_line_to_dashed : + (cairo_spline_add_point_func_t) _cairo_stroker_spline_to; + + if (! _cairo_spline_init (&spline, + spline_to, + stroker, + &stroker->current_point, b, c, d)) + { + cairo_slope_t fallback_slope; + _cairo_slope_init (&fallback_slope, &stroker->current_point, d); + return line_to (closure, d, &fallback_slope); + } + + /* 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; + + /* Compute the initial face */ + if (! stroker->dash.dashed || stroker->dash.dash_on) { + slope_dx = _cairo_fixed_to_double (spline.initial_slope.dx); + slope_dy = _cairo_fixed_to_double (spline.initial_slope.dy); + if (_compute_normalized_device_slope (&slope_dx, &slope_dy, + stroker->ctm_inverse, NULL)) + { + _compute_face (&stroker->current_point, + &spline.initial_slope, + slope_dx, slope_dy, + stroker, &face); + } + if (stroker->has_current_face) { + status = _cairo_stroker_join (stroker, + &stroker->current_face, &face); + if (unlikely (status)) + return status; + } else if (! stroker->has_first_face) { + stroker->first_face = face; + stroker->has_first_face = TRUE; + } + + stroker->current_face = face; + stroker->has_current_face = TRUE; + } + + /* Temporarily modify the stroker to use round joins to guarantee + * smooth stroked curves. */ + line_join_save = stroker->style.line_join; + stroker->style.line_join = CAIRO_LINE_JOIN_ROUND; + + status = _cairo_spline_decompose (&spline, stroker->tolerance); + if (unlikely (status)) + return status; + + /* And join the final face */ + if (! stroker->dash.dashed || stroker->dash.dash_on) { + slope_dx = _cairo_fixed_to_double (spline.final_slope.dx); + slope_dy = _cairo_fixed_to_double (spline.final_slope.dy); + if (_compute_normalized_device_slope (&slope_dx, &slope_dy, + stroker->ctm_inverse, NULL)) + { + _compute_face (&stroker->current_point, + &spline.final_slope, + slope_dx, slope_dy, + stroker, &face); + } + + status = _cairo_stroker_join (stroker, &stroker->current_face, &face); + if (unlikely (status)) + return status; + + stroker->current_face = face; + } + + stroker->style.line_join = line_join_save; + + return CAIRO_STATUS_SUCCESS; +} + +static cairo_status_t +_cairo_stroker_close_path (void *closure) +{ + cairo_stroker_t *stroker = closure; + cairo_status_t status; + + if (stroker->dash.dashed) + status = _cairo_stroker_line_to_dashed (stroker, &stroker->first_point); + else + status = _cairo_stroker_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 */ + status = _cairo_stroker_join (stroker, + &stroker->current_face, + &stroker->first_face); + if (unlikely (status)) + return status; + } else { + /* Cap the start and end of the sub path as needed */ + status = _cairo_stroker_add_caps (stroker); + if (unlikely (status)) + return status; + } + + 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_shaper (cairo_path_fixed_t *path, + const cairo_stroke_style_t *stroke_style, + const cairo_matrix_t *ctm, + const cairo_matrix_t *ctm_inverse, + double tolerance, + cairo_status_t (*add_triangle) (void *closure, + const cairo_point_t triangle[3]), + cairo_status_t (*add_triangle_fan) (void *closure, + const cairo_point_t *midpt, + const cairo_point_t *points, + int npoints), + cairo_status_t (*add_convex_quad) (void *closure, + const cairo_point_t quad[4]), + void *closure) +{ + cairo_stroker_t stroker; + cairo_status_t status; + + status = _cairo_stroker_init (&stroker, path, stroke_style, + ctm, ctm_inverse, tolerance, + NULL, 0); + if (unlikely (status)) + return status; + + stroker.add_triangle = add_triangle; + stroker.add_triangle_fan = add_triangle_fan; + stroker.add_convex_quad = add_convex_quad; + stroker.closure = closure; + + status = _cairo_path_fixed_interpret (path, + _cairo_stroker_move_to, + stroker.dash.dashed ? + _cairo_stroker_line_to_dashed : + _cairo_stroker_line_to, + _cairo_stroker_curve_to, + _cairo_stroker_close_path, + &stroker); + + if (unlikely (status)) + goto BAIL; + + /* Cap the start and end of the final sub path as needed */ + status = _cairo_stroker_add_caps (&stroker); + +BAIL: + _cairo_stroker_fini (&stroker); + + return status; +} + +cairo_status_t +_cairo_path_fixed_stroke_dashed_to_polygon (const cairo_path_fixed_t *path, + const cairo_stroke_style_t *stroke_style, + const cairo_matrix_t *ctm, + const cairo_matrix_t *ctm_inverse, + double tolerance, + cairo_polygon_t *polygon) +{ + cairo_stroker_t stroker; + cairo_status_t status; + + status = _cairo_stroker_init (&stroker, path, stroke_style, + ctm, ctm_inverse, tolerance, + polygon->limits, polygon->num_limits); + if (unlikely (status)) + return status; + + stroker.add_external_edge = _cairo_polygon_add_external_edge, + stroker.closure = polygon; + + status = _cairo_path_fixed_interpret (path, + _cairo_stroker_move_to, + stroker.dash.dashed ? + _cairo_stroker_line_to_dashed : + _cairo_stroker_line_to, + _cairo_stroker_curve_to, + _cairo_stroker_close_path, + &stroker); + + if (unlikely (status)) + goto BAIL; + + /* Cap the start and end of the final sub path as needed */ + status = _cairo_stroker_add_caps (&stroker); + +BAIL: + _cairo_stroker_fini (&stroker); + + return status; +} + +cairo_int_status_t +_cairo_path_fixed_stroke_polygon_to_traps (const cairo_path_fixed_t *path, + const cairo_stroke_style_t *stroke_style, + const cairo_matrix_t *ctm, + const cairo_matrix_t *ctm_inverse, + double tolerance, + cairo_traps_t *traps) +{ + cairo_int_status_t status; + cairo_polygon_t polygon; + + _cairo_polygon_init (&polygon, traps->limits, traps->num_limits); + status = _cairo_path_fixed_stroke_to_polygon (path, + stroke_style, + ctm, + ctm_inverse, + tolerance, + &polygon); + if (unlikely (status)) + goto BAIL; + + status = _cairo_polygon_status (&polygon); + if (unlikely (status)) + goto BAIL; + + status = _cairo_bentley_ottmann_tessellate_polygon (traps, &polygon, + CAIRO_FILL_RULE_WINDING); + +BAIL: + _cairo_polygon_fini (&polygon); + + return status; +} |