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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:24:48 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-07 18:24:48 +0000 |
commit | cca66b9ec4e494c1d919bff0f71a820d8afab1fa (patch) | |
tree | 146f39ded1c938019e1ed42d30923c2ac9e86789 /src/helper/geom.cpp | |
parent | Initial commit. (diff) | |
download | inkscape-upstream.tar.xz inkscape-upstream.zip |
Adding upstream version 1.2.2.upstream/1.2.2upstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
-rw-r--r-- | src/helper/geom.cpp | 954 |
1 files changed, 954 insertions, 0 deletions
diff --git a/src/helper/geom.cpp b/src/helper/geom.cpp new file mode 100644 index 0000000..da2b63c --- /dev/null +++ b/src/helper/geom.cpp @@ -0,0 +1,954 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/* + * Specific geometry functions for Inkscape, not provided my lib2geom. + * + * Author: + * Johan Engelen <goejendaagh@zonnet.nl> + * + * Copyright (C) 2008 Johan Engelen + * + * Released under GNU GPL v2+, read the file 'COPYING' for more information. + */ + +#include <algorithm> +#include "helper/geom.h" +#include "helper/geom-curves.h" +#include <2geom/curves.h> +#include <2geom/sbasis-to-bezier.h> + +using Geom::X; +using Geom::Y; + +//################################################################################# +// BOUNDING BOX CALCULATIONS + +/* Fast bbox calculation */ +/* Thanks to Nathan Hurst for suggesting it */ +static void +cubic_bbox (Geom::Coord x000, Geom::Coord y000, Geom::Coord x001, Geom::Coord y001, Geom::Coord x011, Geom::Coord y011, Geom::Coord x111, Geom::Coord y111, Geom::Rect &bbox) +{ + Geom::Coord a, b, c, D; + + bbox[0].expandTo(x111); + bbox[1].expandTo(y111); + + // It already contains (x000,y000) and (x111,y111) + // All points of the Bezier lie in the convex hull of (x000,y000), (x001,y001), (x011,y011) and (x111,y111) + // So, if it also contains (x001,y001) and (x011,y011) we don't have to compute anything else! + // Note that we compute it for the X and Y range separately to make it easier to use them below + bool containsXrange = bbox[0].contains(x001) && bbox[0].contains(x011); + bool containsYrange = bbox[1].contains(y001) && bbox[1].contains(y011); + + /* + * xttt = s * (s * (s * x000 + t * x001) + t * (s * x001 + t * x011)) + t * (s * (s * x001 + t * x011) + t * (s * x011 + t * x111)) + * xttt = s * (s2 * x000 + s * t * x001 + t * s * x001 + t2 * x011) + t * (s2 * x001 + s * t * x011 + t * s * x011 + t2 * x111) + * xttt = s * (s2 * x000 + 2 * st * x001 + t2 * x011) + t * (s2 * x001 + 2 * st * x011 + t2 * x111) + * xttt = s3 * x000 + 2 * s2t * x001 + st2 * x011 + s2t * x001 + 2st2 * x011 + t3 * x111 + * xttt = s3 * x000 + 3s2t * x001 + 3st2 * x011 + t3 * x111 + * xttt = s3 * x000 + (1 - s) 3s2 * x001 + (1 - s) * (1 - s) * 3s * x011 + (1 - s) * (1 - s) * (1 - s) * x111 + * xttt = s3 * x000 + (3s2 - 3s3) * x001 + (3s - 6s2 + 3s3) * x011 + (1 - 2s + s2 - s + 2s2 - s3) * x111 + * xttt = (x000 - 3 * x001 + 3 * x011 - x111) * s3 + + * ( 3 * x001 - 6 * x011 + 3 * x111) * s2 + + * ( 3 * x011 - 3 * x111) * s + + * ( x111) + * xttt' = (3 * x000 - 9 * x001 + 9 * x011 - 3 * x111) * s2 + + * ( 6 * x001 - 12 * x011 + 6 * x111) * s + + * ( 3 * x011 - 3 * x111) + */ + + if (!containsXrange) { + a = 3 * x000 - 9 * x001 + 9 * x011 - 3 * x111; + b = 6 * x001 - 12 * x011 + 6 * x111; + c = 3 * x011 - 3 * x111; + + /* + * s = (-b +/- sqrt (b * b - 4 * a * c)) / 2 * a; + */ + if (fabs (a) < Geom::EPSILON) { + /* s = -c / b */ + if (fabs (b) > Geom::EPSILON) { + double s; + s = -c / b; + if ((s > 0.0) && (s < 1.0)) { + double t = 1.0 - s; + double xttt = s * s * s * x000 + 3 * s * s * t * x001 + 3 * s * t * t * x011 + t * t * t * x111; + bbox[0].expandTo(xttt); + } + } + } else { + /* s = (-b +/- sqrt (b * b - 4 * a * c)) / 2 * a; */ + D = b * b - 4 * a * c; + if (D >= 0.0) { + Geom::Coord d, s, t, xttt; + /* Have solution */ + d = sqrt (D); + s = (-b + d) / (2 * a); + if ((s > 0.0) && (s < 1.0)) { + t = 1.0 - s; + xttt = s * s * s * x000 + 3 * s * s * t * x001 + 3 * s * t * t * x011 + t * t * t * x111; + bbox[0].expandTo(xttt); + } + s = (-b - d) / (2 * a); + if ((s > 0.0) && (s < 1.0)) { + t = 1.0 - s; + xttt = s * s * s * x000 + 3 * s * s * t * x001 + 3 * s * t * t * x011 + t * t * t * x111; + bbox[0].expandTo(xttt); + } + } + } + } + + if (!containsYrange) { + a = 3 * y000 - 9 * y001 + 9 * y011 - 3 * y111; + b = 6 * y001 - 12 * y011 + 6 * y111; + c = 3 * y011 - 3 * y111; + + if (fabs (a) < Geom::EPSILON) { + /* s = -c / b */ + if (fabs (b) > Geom::EPSILON) { + double s; + s = -c / b; + if ((s > 0.0) && (s < 1.0)) { + double t = 1.0 - s; + double yttt = s * s * s * y000 + 3 * s * s * t * y001 + 3 * s * t * t * y011 + t * t * t * y111; + bbox[1].expandTo(yttt); + } + } + } else { + /* s = (-b +/- sqrt (b * b - 4 * a * c)) / 2 * a; */ + D = b * b - 4 * a * c; + if (D >= 0.0) { + Geom::Coord d, s, t, yttt; + /* Have solution */ + d = sqrt (D); + s = (-b + d) / (2 * a); + if ((s > 0.0) && (s < 1.0)) { + t = 1.0 - s; + yttt = s * s * s * y000 + 3 * s * s * t * y001 + 3 * s * t * t * y011 + t * t * t * y111; + bbox[1].expandTo(yttt); + } + s = (-b - d) / (2 * a); + if ((s > 0.0) && (s < 1.0)) { + t = 1.0 - s; + yttt = s * s * s * y000 + 3 * s * s * t * y001 + 3 * s * t * t * y011 + t * t * t * y111; + bbox[1].expandTo(yttt); + } + } + } + } +} + +Geom::OptRect +bounds_fast_transformed(Geom::PathVector const & pv, Geom::Affine const & t) +{ + return bounds_exact_transformed(pv, t); //use this as it is faster for now! :) +// return Geom::bounds_fast(pv * t); +} + +Geom::OptRect +bounds_exact_transformed(Geom::PathVector const & pv, Geom::Affine const & t) +{ + if (pv.empty()) + return Geom::OptRect(); + + Geom::Point initial = pv.front().initialPoint() * t; + Geom::Rect bbox(initial, initial); // obtain well defined bbox as starting point to unionWith + + for (const auto & it : pv) { + bbox.expandTo(it.initialPoint() * t); + + // don't loop including closing segment, since that segment can never increase the bbox + for (Geom::Path::const_iterator cit = it.begin(); cit != it.end_open(); ++cit) { + Geom::Curve const &c = *cit; + + unsigned order = 0; + if (Geom::BezierCurve const* b = dynamic_cast<Geom::BezierCurve const*>(&c)) { + order = b->order(); + } + + if (order == 1) { // line segment + bbox.expandTo(c.finalPoint() * t); + + // TODO: we can make the case for quadratics faster by degree elevating them to + // cubic and then taking the bbox of that. + + } else if (order == 3) { // cubic bezier + Geom::CubicBezier const &cubic_bezier = static_cast<Geom::CubicBezier const&>(c); + Geom::Point c0 = cubic_bezier[0] * t; + Geom::Point c1 = cubic_bezier[1] * t; + Geom::Point c2 = cubic_bezier[2] * t; + Geom::Point c3 = cubic_bezier[3] * t; + cubic_bbox(c0[0], c0[1], c1[0], c1[1], c2[0], c2[1], c3[0], c3[1], bbox); + } else { + // should handle all not-so-easy curves: + Geom::Curve *ctemp = cit->transformed(t); + bbox.unionWith( ctemp->boundsExact()); + delete ctemp; + } + } + } + //return Geom::bounds_exact(pv * t); + return bbox; +} + +bool +pathv_similar(Geom::PathVector const &apv, Geom::PathVector const &bpv, double precission) +{ + if (apv == bpv) { + return true; + } + size_t totala = apv.curveCount(); + if (totala != bpv.curveCount()) { + return false; + } + std::vector<Geom::Coord> pos; + for (size_t i = 0; i < totala; i++) { + Geom::Point pointa = apv.pointAt(float(i)+0.2); + Geom::Point pointb = bpv.pointAt(float(i)+0.2); + Geom::Point pointc = apv.pointAt(float(i)+0.4); + Geom::Point pointd = bpv.pointAt(float(i)+0.4); + Geom::Point pointe = apv.pointAt(float(i)); + Geom::Point pointf = bpv.pointAt(float(i)); + if (!Geom::are_near(pointa[Geom::X], pointb[Geom::X], precission) || + !Geom::are_near(pointa[Geom::Y], pointb[Geom::Y], precission) || + !Geom::are_near(pointc[Geom::X], pointd[Geom::X], precission) || + !Geom::are_near(pointc[Geom::Y], pointd[Geom::Y], precission) || + !Geom::are_near(pointe[Geom::X], pointf[Geom::X], precission) || + !Geom::are_near(pointe[Geom::Y], pointf[Geom::Y], precission)) + { + return false; + } + } + return true; +} + +static void +geom_line_wind_distance (Geom::Coord x0, Geom::Coord y0, Geom::Coord x1, Geom::Coord y1, Geom::Point const &pt, int *wind, Geom::Coord *best) +{ + Geom::Coord Ax, Ay, Bx, By, Dx, Dy, s; + Geom::Coord dist2; + + /* Find distance */ + Ax = x0; + Ay = y0; + Bx = x1; + By = y1; + Dx = x1 - x0; + Dy = y1 - y0; + const Geom::Coord Px = pt[X]; + const Geom::Coord Py = pt[Y]; + + if (best) { + s = ((Px - Ax) * Dx + (Py - Ay) * Dy) / (Dx * Dx + Dy * Dy); + if (s <= 0.0) { + dist2 = (Px - Ax) * (Px - Ax) + (Py - Ay) * (Py - Ay); + } else if (s >= 1.0) { + dist2 = (Px - Bx) * (Px - Bx) + (Py - By) * (Py - By); + } else { + Geom::Coord Qx, Qy; + Qx = Ax + s * Dx; + Qy = Ay + s * Dy; + dist2 = (Px - Qx) * (Px - Qx) + (Py - Qy) * (Py - Qy); + } + + if (dist2 < (*best * *best)) *best = sqrt (dist2); + } + + if (wind) { + /* Find wind */ + if ((Ax >= Px) && (Bx >= Px)) return; + if ((Ay >= Py) && (By >= Py)) return; + if ((Ay < Py) && (By < Py)) return; + if (Ay == By) return; + /* Ctach upper y bound */ + if (Ay == Py) { + if (Ax < Px) *wind -= 1; + return; + } else if (By == Py) { + if (Bx < Px) *wind += 1; + return; + } else { + Geom::Coord Qx; + /* Have to calculate intersection */ + Qx = Ax + Dx * (Py - Ay) / Dy; + if (Qx < Px) { + *wind += (Dy > 0.0) ? 1 : -1; + } + } + } +} + +static void +geom_cubic_bbox_wind_distance (Geom::Coord x000, Geom::Coord y000, + Geom::Coord x001, Geom::Coord y001, + Geom::Coord x011, Geom::Coord y011, + Geom::Coord x111, Geom::Coord y111, + Geom::Point const &pt, + Geom::Rect *bbox, int *wind, Geom::Coord *best, + Geom::Coord tolerance) +{ + Geom::Coord x0, y0, x1, y1, len2; + int needdist, needwind; + + const Geom::Coord Px = pt[X]; + const Geom::Coord Py = pt[Y]; + + needdist = 0; + needwind = 0; + + if (bbox) cubic_bbox (x000, y000, x001, y001, x011, y011, x111, y111, *bbox); + + x0 = std::min (x000, x001); + x0 = std::min (x0, x011); + x0 = std::min (x0, x111); + y0 = std::min (y000, y001); + y0 = std::min (y0, y011); + y0 = std::min (y0, y111); + x1 = std::max (x000, x001); + x1 = std::max (x1, x011); + x1 = std::max (x1, x111); + y1 = std::max (y000, y001); + y1 = std::max (y1, y011); + y1 = std::max (y1, y111); + + if (best) { + /* Quickly adjust to endpoints */ + len2 = (x000 - Px) * (x000 - Px) + (y000 - Py) * (y000 - Py); + if (len2 < (*best * *best)) *best = (Geom::Coord) sqrt (len2); + len2 = (x111 - Px) * (x111 - Px) + (y111 - Py) * (y111 - Py); + if (len2 < (*best * *best)) *best = (Geom::Coord) sqrt (len2); + + if (((x0 - Px) < *best) && ((y0 - Py) < *best) && ((Px - x1) < *best) && ((Py - y1) < *best)) { + /* Point is inside sloppy bbox */ + /* Now we have to decide, whether subdivide */ + /* fixme: (Lauris) */ + if (((y1 - y0) > 5.0) || ((x1 - x0) > 5.0)) { + needdist = 1; + } + } + } + if (!needdist && wind) { + if ((y1 >= Py) && (y0 < Py) && (x0 < Px)) { + /* Possible intersection at the left */ + /* Now we have to decide, whether subdivide */ + /* fixme: (Lauris) */ + if (((y1 - y0) > 5.0) || ((x1 - x0) > 5.0)) { + needwind = 1; + } + } + } + + if (needdist || needwind) { + Geom::Coord x00t, x0tt, xttt, x1tt, x11t, x01t; + Geom::Coord y00t, y0tt, yttt, y1tt, y11t, y01t; + Geom::Coord s, t; + + t = 0.5; + s = 1 - t; + + x00t = s * x000 + t * x001; + x01t = s * x001 + t * x011; + x11t = s * x011 + t * x111; + x0tt = s * x00t + t * x01t; + x1tt = s * x01t + t * x11t; + xttt = s * x0tt + t * x1tt; + + y00t = s * y000 + t * y001; + y01t = s * y001 + t * y011; + y11t = s * y011 + t * y111; + y0tt = s * y00t + t * y01t; + y1tt = s * y01t + t * y11t; + yttt = s * y0tt + t * y1tt; + + geom_cubic_bbox_wind_distance (x000, y000, x00t, y00t, x0tt, y0tt, xttt, yttt, pt, nullptr, wind, best, tolerance); + geom_cubic_bbox_wind_distance (xttt, yttt, x1tt, y1tt, x11t, y11t, x111, y111, pt, nullptr, wind, best, tolerance); + } else { + geom_line_wind_distance (x000, y000, x111, y111, pt, wind, best); + } +} + +static void +geom_curve_bbox_wind_distance(Geom::Curve const & c, Geom::Affine const &m, + Geom::Point const &pt, + Geom::Rect *bbox, int *wind, Geom::Coord *dist, + Geom::Coord tolerance, Geom::Rect const *viewbox, + Geom::Point &p0) // pass p0 through as it represents the last endpoint added (the finalPoint of last curve) +{ + unsigned order = 0; + if (Geom::BezierCurve const* b = dynamic_cast<Geom::BezierCurve const*>(&c)) { + order = b->order(); + } + if (order == 1) { + Geom::Point pe = c.finalPoint() * m; + if (bbox) { + bbox->expandTo(pe); + } + if (dist || wind) { + if (wind) { // we need to pick fill, so do what we're told + geom_line_wind_distance (p0[X], p0[Y], pe[X], pe[Y], pt, wind, dist); + } else { // only stroke is being picked; skip this segment if it's totally outside the viewbox + Geom::Rect swept(p0, pe); + if (!viewbox || swept.intersects(*viewbox)) + geom_line_wind_distance (p0[X], p0[Y], pe[X], pe[Y], pt, wind, dist); + } + } + p0 = pe; + } + else if (order == 3) { + Geom::CubicBezier const& cubic_bezier = static_cast<Geom::CubicBezier const&>(c); + Geom::Point p1 = cubic_bezier[1] * m; + Geom::Point p2 = cubic_bezier[2] * m; + Geom::Point p3 = cubic_bezier[3] * m; + + // get approximate bbox from handles (convex hull property of beziers): + Geom::Rect swept(p0, p3); + swept.expandTo(p1); + swept.expandTo(p2); + + if (!viewbox || swept.intersects(*viewbox)) { // we see this segment, so do full processing + geom_cubic_bbox_wind_distance ( p0[X], p0[Y], + p1[X], p1[Y], + p2[X], p2[Y], + p3[X], p3[Y], + pt, + bbox, wind, dist, tolerance); + } else { + if (wind) { // if we need fill, we can just pretend it's a straight line + geom_line_wind_distance (p0[X], p0[Y], p3[X], p3[Y], pt, wind, dist); + } else { // otherwise, skip it completely + } + } + p0 = p3; + } else { + //this case handles sbasis as well as all other curve types + Geom::Path sbasis_path = Geom::cubicbezierpath_from_sbasis(c.toSBasis(), 0.1); + + //recurse to convert the new path resulting from the sbasis to svgd + for (const auto & iter : sbasis_path) { + geom_curve_bbox_wind_distance(iter, m, pt, bbox, wind, dist, tolerance, viewbox, p0); + } + } +} + +bool +pointInTriangle(Geom::Point const &p, Geom::Point const &p1, Geom::Point const &p2, Geom::Point const &p3) +{ + //http://totologic.blogspot.com.es/2014/01/accurate-point-in-triangle-test.html + using Geom::X; + using Geom::Y; + double denominator = (p1[X]*(p2[Y] - p3[Y]) + p1[Y]*(p3[X] - p2[X]) + p2[X]*p3[Y] - p2[Y]*p3[X]); + double t1 = (p[X]*(p3[Y] - p1[Y]) + p[Y]*(p1[X] - p3[X]) - p1[X]*p3[Y] + p1[Y]*p3[X]) / denominator; + double t2 = (p[X]*(p2[Y] - p1[Y]) + p[Y]*(p1[X] - p2[X]) - p1[X]*p2[Y] + p1[Y]*p2[X]) / -denominator; + double s = t1 + t2; + + return 0 <= t1 && t1 <= 1 && 0 <= t2 && t2 <= 1 && s <= 1; +} + + +/* Calculates... + and returns ... in *wind and the distance to ... in *dist. + Returns bounding box in *bbox if bbox!=NULL. + */ +void +pathv_matrix_point_bbox_wind_distance (Geom::PathVector const & pathv, Geom::Affine const &m, Geom::Point const &pt, + Geom::Rect *bbox, int *wind, Geom::Coord *dist, + Geom::Coord tolerance, Geom::Rect const *viewbox) +{ + if (pathv.empty()) { + if (wind) *wind = 0; + if (dist) *dist = Geom::infinity(); + return; + } + + // remember last point of last curve + Geom::Point p0(0,0); + + // remembering the start of subpath + Geom::Point p_start(0,0); + bool start_set = false; + + for (const auto & it : pathv) { + + if (start_set) { // this is a new subpath + if (wind && (p0 != p_start)) // for correct fill picking, each subpath must be closed + geom_line_wind_distance (p0[X], p0[Y], p_start[X], p_start[Y], pt, wind, dist); + } + p0 = it.initialPoint() * m; + p_start = p0; + start_set = true; + if (bbox) { + bbox->expandTo(p0); + } + + // loop including closing segment if path is closed + for (Geom::Path::const_iterator cit = it.begin(); cit != it.end_default(); ++cit) { + geom_curve_bbox_wind_distance(*cit, m, pt, bbox, wind, dist, tolerance, viewbox, p0); + } + } + + if (start_set) { + if (wind && (p0 != p_start)) // for correct picking, each subpath must be closed + geom_line_wind_distance (p0[X], p0[Y], p_start[X], p_start[Y], pt, wind, dist); + } +} + +//################################################################################# + +/** + * Basic check on intersecting path vectors + */ +bool is_intersecting(Geom::PathVector const&a, Geom::PathVector const&b) { + for (auto &node : b.nodes()) { + if (a.winding(node)) { + return true; + } + } + for (auto &node : a.nodes()) { + if (b.winding(node)) { + return true; + } + } + return false; +} + +/* + * Converts all segments in all paths to Geom::LineSegment or Geom::HLineSegment or + * Geom::VLineSegment or Geom::CubicBezier. + */ +Geom::PathVector +pathv_to_linear_and_cubic_beziers( Geom::PathVector const &pathv ) +{ + Geom::PathVector output; + + for (const auto & pit : pathv) { + output.push_back( Geom::Path() ); + output.back().setStitching(true); + output.back().start( pit.initialPoint() ); + + for (Geom::Path::const_iterator cit = pit.begin(); cit != pit.end_open(); ++cit) { + if (is_straight_curve(*cit)) { + Geom::LineSegment l(cit->initialPoint(), cit->finalPoint()); + output.back().append(l); + } else { + Geom::BezierCurve const *curve = dynamic_cast<Geom::BezierCurve const *>(&*cit); + if (curve && curve->order() == 3) { + Geom::CubicBezier b((*curve)[0], (*curve)[1], (*curve)[2], (*curve)[3]); + output.back().append(b); + } else { + // convert all other curve types to cubicbeziers + Geom::Path cubicbezier_path = Geom::cubicbezierpath_from_sbasis(cit->toSBasis(), 0.1); + cubicbezier_path.close(false); + output.back().append(cubicbezier_path); + } + } + } + + output.back().close( pit.closed() ); + } + + return output; +} + +/* + * Converts all segments in all paths to Geom::LineSegment. There is an intermediate + * stage where some may be converted to beziers. maxdisp is the maximum displacement from + * the line segment to the bezier curve; ** maxdisp is not used at this moment **. + * + * This is NOT a terribly fast method, but it should give a solution close to the one with the + * fewest points. + */ +Geom::PathVector +pathv_to_linear( Geom::PathVector const &pathv, double /*maxdisp*/) +{ + Geom::PathVector output; + Geom::PathVector tmppath = pathv_to_linear_and_cubic_beziers(pathv); + + // Now all path segments are either already lines, or they are beziers. + + for (const auto & pit : tmppath) { + output.push_back( Geom::Path() ); + output.back().start( pit.initialPoint() ); + output.back().close( pit.closed() ); + + for (Geom::Path::const_iterator cit = pit.begin(); cit != pit.end_open(); ++cit) { + if (is_straight_curve(*cit)) { + Geom::LineSegment ls(cit->initialPoint(), cit->finalPoint()); + output.back().append(ls); + } + else { /* all others must be Bezier curves */ + Geom::BezierCurve const *curve = dynamic_cast<Geom::BezierCurve const *>(&*cit); + std::vector<Geom::Point> bzrpoints = curve->controlPoints(); + Geom::Point A = bzrpoints[0]; + Geom::Point B = bzrpoints[1]; + Geom::Point C = bzrpoints[2]; + Geom::Point D = bzrpoints[3]; + std::vector<Geom::Point> pointlist; + pointlist.push_back(A); + recursive_bezier4( + A[X], A[Y], + B[X], B[Y], + C[X], C[Y], + D[X], D[Y], + pointlist, + 0); + pointlist.push_back(D); + Geom::Point r1 = pointlist[0]; + for (unsigned int i=1; i<pointlist.size();i++){ + Geom::Point prev_r1 = r1; + r1 = pointlist[i]; + Geom::LineSegment ls(prev_r1, r1); + output.back().append(ls); + } + pointlist.clear(); + } + } + } + + return output; +} + +/* + * Converts all segments in all paths to Geom Cubic bezier. + * This is used in lattice2 LPE, maybe is better move the function to the effect + * But maybe could be usable by others, so i put here. + * The straight curve part is needed as is for the effect to work appropriately + */ +Geom::PathVector +pathv_to_cubicbezier( Geom::PathVector const &pathv) +{ + Geom::PathVector output; + double cubicGap = 0.01; + for (const auto & pit : pathv) { + if (pit.empty()) { + continue; + } + output.push_back( Geom::Path() ); + output.back().start( pit.initialPoint() ); + output.back().close( pit.closed() ); + bool end_open = false; + if (pit.closed()) { + const Geom::Curve &closingline = pit.back_closed(); + if (!are_near(closingline.initialPoint(), closingline.finalPoint())) { + end_open = true; + } + } + Geom::Path pitCubic = (Geom::Path)pit; + if(end_open && pit.closed()){ + pitCubic.close(false); + pitCubic.appendNew<Geom::LineSegment>( pitCubic.initialPoint() ); + pitCubic.close(true); + } + for (Geom::Path::iterator cit = pitCubic.begin(); cit != pitCubic.end_open(); ++cit) { + if (is_straight_curve(*cit)) { + Geom::CubicBezier b(cit->initialPoint(), cit->pointAt(0.3334) + Geom::Point(cubicGap,cubicGap), cit->finalPoint(), cit->finalPoint()); + output.back().append(b); + } else { + Geom::BezierCurve const *curve = dynamic_cast<Geom::BezierCurve const *>(&*cit); + if (curve && curve->order() == 3) { + Geom::CubicBezier b((*curve)[0], (*curve)[1], (*curve)[2], (*curve)[3]); + output.back().append(b); + } else { + // convert all other curve types to cubicbeziers + Geom::Path cubicbezier_path = Geom::cubicbezierpath_from_sbasis(cit->toSBasis(), 0.1); + output.back().append(cubicbezier_path); + } + } + } + } + + return output; +} + +//Study move to 2Geom +size_t +count_pathvector_nodes(Geom::PathVector const &pathv) { + size_t tot = 0; + for (auto subpath : pathv) { + tot += count_path_nodes(subpath); + } + return tot; +} +size_t count_path_nodes(Geom::Path const &path) +{ + size_t tot = path.size_closed(); + if (path.closed()) { + const Geom::Curve &closingline = path.back_closed(); + // the closing line segment is always of type + // Geom::LineSegment. + if (are_near(closingline.initialPoint(), closingline.finalPoint())) { + // closingline.isDegenerate() did not work, because it only checks for + // *exact* zero length, which goes wrong for relative coordinates and + // rounding errors... + // the closing line segment has zero-length. So stop before that one! + tot -= 1; + } + } + return tot; +} + +// The next routine is modified from curv4_div::recursive_bezier from file agg_curves.cpp +//---------------------------------------------------------------------------- +// Anti-Grain Geometry (AGG) - Version 2.5 +// A high quality rendering engine for C++ +// Copyright (C) 2002-2006 Maxim Shemanarev +// Contact: mcseem@antigrain.com +// mcseemagg@yahoo.com +// http://antigrain.com +// +// AGG is free software; you can redistribute it and/or +// modify it under the terms of the GNU General Public License +// as published by the Free Software Foundation; either version 2 +// of the License, or (at your option) any later version. +// +// AGG is distributed in the hope that it will be useful, +// but WITHOUT ANY WARRANTY; without even the implied warranty of +// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the +// GNU General Public License for more details. +// +// You should have received a copy of the GNU General Public License +// along with AGG; if not, write to the Free Software +// Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, +// MA 02110-1301, USA. +//---------------------------------------------------------------------------- +void +recursive_bezier4(const double x1, const double y1, + const double x2, const double y2, + const double x3, const double y3, + const double x4, const double y4, + std::vector<Geom::Point> &m_points, + int level) + { + // some of these should be parameters, but do it this way for now. + const double curve_collinearity_epsilon = 1e-30; + const double curve_angle_tolerance_epsilon = 0.01; + double m_cusp_limit = 0.0; + double m_angle_tolerance = 0.0; + double m_approximation_scale = 1.0; + double m_distance_tolerance_square = 0.5 / m_approximation_scale; + m_distance_tolerance_square *= m_distance_tolerance_square; + enum curve_recursion_limit_e { curve_recursion_limit = 32 }; +#define calc_sq_distance(A,B,C,D) ((A-C)*(A-C) + (B-D)*(B-D)) + + if(level > curve_recursion_limit) + { + return; + } + + + // Calculate all the mid-points of the line segments + //---------------------- + double x12 = (x1 + x2) / 2; + double y12 = (y1 + y2) / 2; + double x23 = (x2 + x3) / 2; + double y23 = (y2 + y3) / 2; + double x34 = (x3 + x4) / 2; + double y34 = (y3 + y4) / 2; + double x123 = (x12 + x23) / 2; + double y123 = (y12 + y23) / 2; + double x234 = (x23 + x34) / 2; + double y234 = (y23 + y34) / 2; + double x1234 = (x123 + x234) / 2; + double y1234 = (y123 + y234) / 2; + + + // Try to approximate the full cubic curve by a single straight line + //------------------ + double dx = x4-x1; + double dy = y4-y1; + + double d2 = fabs(((x2 - x4) * dy - (y2 - y4) * dx)); + double d3 = fabs(((x3 - x4) * dy - (y3 - y4) * dx)); + double da1, da2, k; + + switch((int(d2 > curve_collinearity_epsilon) << 1) + + int(d3 > curve_collinearity_epsilon)) + { + case 0: + // All collinear OR p1==p4 + //---------------------- + k = dx*dx + dy*dy; + if(k == 0) + { + d2 = calc_sq_distance(x1, y1, x2, y2); + d3 = calc_sq_distance(x4, y4, x3, y3); + } + else + { + k = 1 / k; + da1 = x2 - x1; + da2 = y2 - y1; + d2 = k * (da1*dx + da2*dy); + da1 = x3 - x1; + da2 = y3 - y1; + d3 = k * (da1*dx + da2*dy); + if(d2 > 0 && d2 < 1 && d3 > 0 && d3 < 1) + { + // Simple collinear case, 1---2---3---4 + // We can leave just two endpoints + return; + } + if(d2 <= 0) d2 = calc_sq_distance(x2, y2, x1, y1); + else if(d2 >= 1) d2 = calc_sq_distance(x2, y2, x4, y4); + else d2 = calc_sq_distance(x2, y2, x1 + d2*dx, y1 + d2*dy); + + if(d3 <= 0) d3 = calc_sq_distance(x3, y3, x1, y1); + else if(d3 >= 1) d3 = calc_sq_distance(x3, y3, x4, y4); + else d3 = calc_sq_distance(x3, y3, x1 + d3*dx, y1 + d3*dy); + } + if(d2 > d3) + { + if(d2 < m_distance_tolerance_square) + { + m_points.emplace_back(x2, y2); + return; + } + } + else + { + if(d3 < m_distance_tolerance_square) + { + m_points.emplace_back(x3, y3); + return; + } + } + break; + + case 1: + // p1,p2,p4 are collinear, p3 is significant + //---------------------- + if(d3 * d3 <= m_distance_tolerance_square * (dx*dx + dy*dy)) + { + if(m_angle_tolerance < curve_angle_tolerance_epsilon) + { + m_points.emplace_back(x23, y23); + return; + } + + // Angle Condition + //---------------------- + da1 = fabs(atan2(y4 - y3, x4 - x3) - atan2(y3 - y2, x3 - x2)); + if(da1 >= M_PI) da1 = 2*M_PI - da1; + + if(da1 < m_angle_tolerance) + { + m_points.emplace_back(x2, y2); + m_points.emplace_back(x3, y3); + return; + } + + if(m_cusp_limit != 0.0) + { + if(da1 > m_cusp_limit) + { + m_points.emplace_back(x3, y3); + return; + } + } + } + break; + + case 2: + // p1,p3,p4 are collinear, p2 is significant + //---------------------- + if(d2 * d2 <= m_distance_tolerance_square * (dx*dx + dy*dy)) + { + if(m_angle_tolerance < curve_angle_tolerance_epsilon) + { + m_points.emplace_back(x23, y23); + return; + } + + // Angle Condition + //---------------------- + da1 = fabs(atan2(y3 - y2, x3 - x2) - atan2(y2 - y1, x2 - x1)); + if(da1 >= M_PI) da1 = 2*M_PI - da1; + + if(da1 < m_angle_tolerance) + { + m_points.emplace_back(x2, y2); + m_points.emplace_back(x3, y3); + return; + } + + if(m_cusp_limit != 0.0) + { + if(da1 > m_cusp_limit) + { + m_points.emplace_back(x2, y2); + return; + } + } + } + break; + + case 3: + // Regular case + //----------------- + if((d2 + d3)*(d2 + d3) <= m_distance_tolerance_square * (dx*dx + dy*dy)) + { + // If the curvature doesn't exceed the distance_tolerance value + // we tend to finish subdivisions. + //---------------------- + if(m_angle_tolerance < curve_angle_tolerance_epsilon) + { + m_points.emplace_back(x23, y23); + return; + } + + // Angle & Cusp Condition + //---------------------- + k = atan2(y3 - y2, x3 - x2); + da1 = fabs(k - atan2(y2 - y1, x2 - x1)); + da2 = fabs(atan2(y4 - y3, x4 - x3) - k); + if(da1 >= M_PI) da1 = 2*M_PI - da1; + if(da2 >= M_PI) da2 = 2*M_PI - da2; + + if(da1 + da2 < m_angle_tolerance) + { + // Finally we can stop the recursion + //---------------------- + m_points.emplace_back(x23, y23); + return; + } + + if(m_cusp_limit != 0.0) + { + if(da1 > m_cusp_limit) + { + m_points.emplace_back(x2, y2); + return; + } + + if(da2 > m_cusp_limit) + { + m_points.emplace_back(x3, y3); + return; + } + } + } + break; + } + + // Continue subdivision + //---------------------- + recursive_bezier4(x1, y1, x12, y12, x123, y123, x1234, y1234, m_points, level + 1); + recursive_bezier4(x1234, y1234, x234, y234, x34, y34, x4, y4, m_points, level + 1); +} + +void +swap(Geom::Point &A, Geom::Point &B){ + Geom::Point tmp = A; + A = B; + B = tmp; +} + +/* + Local Variables: + mode:c++ + c-file-style:"stroustrup" + c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +)) + indent-tabs-mode:nil + fill-column:99 + End: +*/ +// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 : |