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Diffstat (limited to 'src/live_effects/lpe-powerstroke.cpp')
| -rw-r--r-- | src/live_effects/lpe-powerstroke.cpp | 820 |
1 files changed, 820 insertions, 0 deletions
diff --git a/src/live_effects/lpe-powerstroke.cpp b/src/live_effects/lpe-powerstroke.cpp new file mode 100644 index 0000000..63c5bae --- /dev/null +++ b/src/live_effects/lpe-powerstroke.cpp @@ -0,0 +1,820 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +/** + * @file + * PowerStroke LPE implementation. Creates curves with modifiable stroke width. + */ +/* Authors: + * Johan Engelen <j.b.c.engelen@alumnus.utwente.nl> + * + * Copyright (C) 2010-2012 Authors + * + * Released under GNU GPL v2+, read the file 'COPYING' for more information. + */ + +#include <2geom/elliptical-arc.h> +#include <2geom/path-sink.h> +#include <2geom/path-intersection.h> +#include <2geom/circle.h> + +#include "live_effects/lpe-powerstroke.h" +#include "live_effects/lpe-powerstroke-interpolators.h" +#include "live_effects/lpe-simplify.h" +#include "live_effects/lpeobject.h" +#include "live_effects/fill-conversion.h" + +#include "desktop-style.h" +#include "style.h" + +#include "display/curve.h" +#include "display/control/canvas-item-enums.h" +#include "helper/geom.h" +#include "object/sp-shape.h" +#include "svg/css-ostringstream.h" +#include "svg/svg-color.h" + +// TODO due to internal breakage in glibmm headers, this must be last: +#include <glibmm/i18n.h> + +namespace Geom { +// should all be moved to 2geom at some point + +/** Find the point where two straight lines cross. +*/ +static std::optional<Point> intersection_point( Point const & origin_a, Point const & vector_a, + Point const & origin_b, Point const & vector_b) +{ + Coord denom = cross(vector_a, vector_b); + if (!are_near(denom,0.)){ + Coord t = (cross(vector_b, origin_a) + cross(origin_b, vector_b)) / denom; + return origin_a + t * vector_a; + } + return std::nullopt; +} + +static Geom::CubicBezier sbasis_to_cubicbezier(Geom::D2<Geom::SBasis> const & sbasis_in) +{ + std::vector<Geom::Point> temp; + sbasis_to_bezier(temp, sbasis_in, 4); + return Geom::CubicBezier( temp ); +} + +/** + * document this! + * very quick: this finds the ellipse with minimum eccentricity + passing through point P and Q, with tangent PO at P and QO at Q + http://mathforum.org/kb/message.jspa?messageID=7471596&tstart=0 + */ +static Ellipse find_ellipse(Point P, Point Q, Point O) +{ + Point p = P - O; + Point q = Q - O; + Coord K = 4 * dot(p,q) / (L2sq(p) + L2sq(q)); + + double cross = p[Y]*q[X] - p[X]*q[Y]; + double a = -q[Y]/cross; + double b = q[X]/cross; + double c = (O[X]*q[Y] - O[Y]*q[X])/cross; + + double d = p[Y]/cross; + double e = -p[X]/cross; + double f = (-O[X]*p[Y] + O[Y]*p[X])/cross; + + // Ax^2 + Bxy + Cy^2 + Dx + Ey + F = 0 + double A = (a*d*K+d*d+a*a); + double B = (a*e*K+b*d*K+2*d*e+2*a*b); + double C = (b*e*K+e*e+b*b); + double D = (a*f*K+c*d*K+2*d*f-2*d+2*a*c-2*a); + double E = (b*f*K+c*e*K+2*e*f-2*e+2*b*c-2*b); + double F = c*f*K+f*f-2*f+c*c-2*c+1; + + return Ellipse(A, B, C, D, E, F); +} + +/** + * Find circle that touches inside of the curve, with radius matching the curvature, at time value \c t. + * Because this method internally uses unitTangentAt, t should be smaller than 1.0 (see unitTangentAt). + */ +static Circle touching_circle( D2<SBasis> const &curve, double t, double tol=0.01 ) +{ + //Piecewise<SBasis> k = curvature(curve, tol); + D2<SBasis> dM=derivative(curve); + if ( are_near(L2sq(dM(t)),0.) && (dM[0].size() > 1) && (dM[1].size() > 1) ) { + dM=derivative(dM); + } + if ( are_near(L2sq(dM(t)),0.) && (dM[0].size() > 1) && (dM[1].size() > 1) ) { // try second time + dM=derivative(dM); + } + if ( dM.isZero(tol) || (are_near(L2sq(dM(t)),0.) && (dM[0].size() > 1) && (dM[1].size() > 1) )) { // admit defeat + return Geom::Circle(Geom::Point(0., 0.), 0.); + } + Piecewise<D2<SBasis> > unitv = unitVector(dM,tol); + if (unitv.empty()) { // admit defeat + return Geom::Circle(Geom::Point(0., 0.), 0.); + } + Piecewise<SBasis> dMlength = dot(Piecewise<D2<SBasis> >(dM),unitv); + Piecewise<SBasis> k = cross(derivative(unitv),unitv); + k = divide(k,dMlength,tol,3); + double curv = k(t); // note that this value is signed + + Geom::Point normal = unitTangentAt(curve, t).cw(); + double radius = 1/curv; + Geom::Point center = curve(t) + radius*normal; + return Geom::Circle(center, fabs(radius)); +} + +} // namespace Geom + +namespace Inkscape { +namespace LivePathEffect { + +static const Util::EnumData<unsigned> InterpolatorTypeData[] = { + {Geom::Interpolate::INTERP_CUBICBEZIER_SMOOTH, N_("CubicBezierSmooth"), "CubicBezierSmooth"}, + {Geom::Interpolate::INTERP_LINEAR , N_("Linear"), "Linear"}, + {Geom::Interpolate::INTERP_CUBICBEZIER , N_("CubicBezierFit"), "CubicBezierFit"}, + {Geom::Interpolate::INTERP_CUBICBEZIER_JOHAN , N_("CubicBezierJohan"), "CubicBezierJohan"}, + {Geom::Interpolate::INTERP_SPIRO , N_("SpiroInterpolator"), "SpiroInterpolator"}, + {Geom::Interpolate::INTERP_CENTRIPETAL_CATMULLROM, N_("Centripetal Catmull-Rom"), "CentripetalCatmullRom"} +}; +static const Util::EnumDataConverter<unsigned> InterpolatorTypeConverter(InterpolatorTypeData, sizeof(InterpolatorTypeData)/sizeof(*InterpolatorTypeData)); + +enum LineJoinType { + LINEJOIN_BEVEL, + LINEJOIN_ROUND, + LINEJOIN_EXTRP_MITER, + LINEJOIN_MITER, + LINEJOIN_SPIRO, + LINEJOIN_EXTRP_MITER_ARC +}; +static const Util::EnumData<unsigned> LineJoinTypeData[] = { + {LINEJOIN_BEVEL, N_("Beveled"), "bevel"}, + {LINEJOIN_ROUND, N_("Rounded"), "round"}, +// {LINEJOIN_EXTRP_MITER, N_("Extrapolated"), "extrapolated"}, // disabled because doesn't work well + {LINEJOIN_EXTRP_MITER_ARC, N_("Extrapolated arc"), "extrp_arc"}, + {LINEJOIN_MITER, N_("Miter"), "miter"}, + {LINEJOIN_SPIRO, N_("Spiro"), "spiro"}, +}; +static const Util::EnumDataConverter<unsigned> LineJoinTypeConverter(LineJoinTypeData, sizeof(LineJoinTypeData)/sizeof(*LineJoinTypeData)); + +LPEPowerStroke::LPEPowerStroke(LivePathEffectObject *lpeobject) : + Effect(lpeobject), + offset_points(_("Offset points"), _("Offset points"), "offset_points", &wr, this), + not_jump(_("No jumping handles"), _("Allow to move handles along the path without them automatically attaching to the nearest path segment"), "not_jump", &wr, this, false), + sort_points(_("Sort points"), _("Sort offset points according to their time value along the curve"), "sort_points", &wr, this, true), + interpolator_type(_("Interpolator type:"), _("Determines which kind of interpolator will be used to interpolate between stroke width along the path"), "interpolator_type", InterpolatorTypeConverter, &wr, this, Geom::Interpolate::INTERP_CENTRIPETAL_CATMULLROM), + interpolator_beta(_("Smoothness:"), _("Sets the smoothness for the CubicBezierJohan interpolator; 0 = linear interpolation, 1 = smooth"), "interpolator_beta", &wr, this, 0.2), + scale_width(_("Width factor:"), _("Scale the stroke's width uniformly along the whole path"), "scale_width", &wr, this, 1.0), + start_linecap_type(_("Start cap:"), _("Determines the shape of the path's start"), "start_linecap_type", LineCapTypeConverter, &wr, this, LINECAP_ZERO_WIDTH), + linejoin_type(_("Join:"), _("Determines the shape of the path's corners"), "linejoin_type", LineJoinTypeConverter, &wr, this, LINEJOIN_ROUND), + miter_limit(_("Miter limit:"), _("Maximum length of the miter (in units of stroke width)"), "miter_limit", &wr, this, 4.), + end_linecap_type(_("End cap:"), _("Determines the shape of the path's end"), "end_linecap_type", LineCapTypeConverter, &wr, this, LINECAP_ZERO_WIDTH) +{ + show_orig_path = true; + + /// @todo offset_points are initialized with empty path, is that bug-save? + + interpolator_beta.addSlider(true); + interpolator_beta.param_set_range(0.,1.); + + registerParameter(&offset_points); + registerParameter(¬_jump); + registerParameter(&sort_points); + registerParameter(&interpolator_type); + registerParameter(&interpolator_beta); + registerParameter(&start_linecap_type); + registerParameter(&linejoin_type); + registerParameter(&miter_limit); + registerParameter(&scale_width); + registerParameter(&end_linecap_type); + scale_width.param_set_range(0.0, std::numeric_limits<double>::max()); + scale_width.param_set_increments(0.1, 0.1); + scale_width.param_set_digits(4); + recusion_limit = 0; + has_recursion = false; +} + +LPEPowerStroke::~LPEPowerStroke() = default; + +void +LPEPowerStroke::doBeforeEffect(SPLPEItem const *lpeItem) +{ + offset_points.set_scale_width(scale_width); + if (has_recursion) { + has_recursion = false; + adjustForNewPath(pathvector_before_effect); + } +} + +void LPEPowerStroke::applyStyle(SPLPEItem *lpeitem) +{ + lpe_shape_convert_stroke_and_fill(SP_SHAPE(lpeitem)); +} + +void +LPEPowerStroke::doOnApply(SPLPEItem const* lpeitem) +{ + if (auto shape = dynamic_cast<SPShape const *>(lpeitem)) { + SPLPEItem* item = const_cast<SPLPEItem*>(lpeitem); + std::vector<Geom::Point> points; + Geom::PathVector const &pathv = pathv_to_linear_and_cubic_beziers(shape->curve()->get_pathvector()); + double width = (lpeitem && lpeitem->style) ? lpeitem->style->stroke_width.computed / 2 : 1.; + Inkscape::Preferences *prefs = Inkscape::Preferences::get(); + Glib::ustring pref_path_pp = "/live_effects/powerstroke/powerpencil"; + bool powerpencil = prefs->getBool(pref_path_pp, false); + bool clipboard = offset_points.data().size() > 0; + if (!powerpencil) { + applyStyle(item); + } + if (!clipboard && !powerpencil) { + item->updateRepr(); + if (pathv.empty()) { + points.emplace_back(0.2,width ); + points.emplace_back(0.5, width); + points.emplace_back(0.8, width); + } else { + Geom::Path const &path = pathv.front(); + Geom::Path::size_type const size = path.size_default(); + if (!path.closed()) { + points.emplace_back(0.2, width); + } + points.emplace_back(0.5 * size, width); + if (!path.closed()) { + points.emplace_back(size - 0.2, width); + } + } + offset_points.param_set_and_write_new_value(points); + } + offset_points.set_scale_width(scale_width); + } else { + if (!SP_IS_SHAPE(lpeitem)) { + g_warning("LPE Powerstroke can only be applied to shapes (not groups)."); + } + } +} + +void LPEPowerStroke::doOnRemove(SPLPEItem const* lpeitem) +{ + auto lpeitem_mutable = const_cast<SPLPEItem *>(lpeitem); + auto shape = dynamic_cast<SPShape *>(lpeitem_mutable); + + if (shape && !keep_paths) { + lpe_shape_revert_stroke_and_fill(shape, offset_points.median_width() * 2); + } +} + +void +LPEPowerStroke::adjustForNewPath(Geom::PathVector const & path_in) +{ + if (!path_in.empty()) { + offset_points.recalculate_controlpoints_for_new_pwd2(path_in[0].toPwSb()); + } +} + +static bool compare_offsets (Geom::Point first, Geom::Point second) +{ + return first[Geom::X] < second[Geom::X]; +} + +static Geom::Path path_from_piecewise_fix_cusps( Geom::Piecewise<Geom::D2<Geom::SBasis> > const & B, + Geom::Piecewise<Geom::SBasis> const & y, // width path + LineJoinType jointype, + double miter_limit, + double tol=Geom::EPSILON) +{ +/* per definition, each discontinuity should be fixed with a join-ending, as defined by linejoin_type +*/ + Geom::PathBuilder pb; + Geom::OptRect bbox = bounds_fast(B); + if (B.empty() || !bbox) { + return pb.peek().front(); + } + + pb.setStitching(true); + + Geom::Point start = B[0].at0(); + pb.moveTo(start); + build_from_sbasis(pb, B[0], tol, false); + unsigned prev_i = 0; + for (unsigned i=1; i < B.size(); i++) { + // Skip degenerate segments. The number below was determined, after examining + // very many paths with powerstrokes of all shapes and sizes, to allow filtering out most + // degenerate segments without losing significant quality; it is close to 1/256. + if (B[i].isConstant(4e-3)) { + continue; + } + if (!are_near(B[prev_i].at1(), B[i].at0(), tol) ) + { // discontinuity found, so fix it :-) + double width = y( B.cuts[i] ); + + Geom::Point tang1 = -unitTangentAt(reverse(B[prev_i]),0.); // = unitTangentAt(B[prev_i],1); + Geom::Point tang2 = unitTangentAt(B[i],0); + Geom::Point discontinuity_vec = B[i].at0() - B[prev_i].at1(); + bool on_outside = ( dot(tang1, discontinuity_vec) >= 0. ); + + if (on_outside) { + // we are on the outside: add some type of join! + switch (jointype) { + case LINEJOIN_ROUND: { + /* for constant width paths, the rounding is a circular arc (rx == ry), + for non-constant width paths, the rounding can be done with an ellipse but is hard and ambiguous. + The elliptical arc should go through the discontinuity's start and end points (of course!) + and also should match the discontinuity tangents at those start and end points. + To resolve the ambiguity, the elliptical arc with minimal eccentricity should be chosen. + A 2Geom method was created to do exactly this :) + */ + + std::optional<Geom::Point> O = intersection_point( B[prev_i].at1(), tang1, + B[i].at0(), tang2 ); + if (!O) { + // no center found, i.e. 180 degrees round + pb.lineTo(B[i].at0()); // default to bevel for too shallow cusp angles + break; + } + + Geom::Ellipse ellipse; + try { + ellipse = find_ellipse(B[prev_i].at1(), B[i].at0(), *O); + } + catch (Geom::LogicalError &e) { + // 2geom did not find a fitting ellipse, this happens for weird thick paths :) + // do bevel, and break + pb.lineTo(B[i].at0()); + break; + } + + // check if ellipse.ray is within 'sane' range. + if ( ( fabs(ellipse.ray(Geom::X)) > 1e6 ) || + ( fabs(ellipse.ray(Geom::Y)) > 1e6 ) ) + { + // do bevel, and break + pb.lineTo(B[i].at0()); + break; + } + + pb.arcTo( ellipse.ray(Geom::X), ellipse.ray(Geom::Y), ellipse.rotationAngle(), + false, width < 0, B[i].at0() ); + + break; + } + case LINEJOIN_EXTRP_MITER: { + Geom::D2<Geom::SBasis> newcurve1 = B[prev_i] * Geom::reflection(rot90(tang1), B[prev_i].at1()); + Geom::CubicBezier bzr1 = sbasis_to_cubicbezier( reverse(newcurve1) ); + + Geom::D2<Geom::SBasis> newcurve2 = B[i] * Geom::reflection(rot90(tang2), B[i].at0()); + Geom::CubicBezier bzr2 = sbasis_to_cubicbezier( reverse(newcurve2) ); + + Geom::Crossings cross = crossings(bzr1, bzr2); + if (cross.empty()) { + // empty crossing: default to bevel + pb.lineTo(B[i].at0()); + } else { + // check size of miter + Geom::Point point_on_path = B[prev_i].at1() - rot90(tang1) * width; + Geom::Coord len = distance(bzr1.pointAt(cross[0].ta), point_on_path); + if (len > fabs(width) * miter_limit) { + // miter too big: default to bevel + pb.lineTo(B[i].at0()); + } else { + std::pair<Geom::CubicBezier, Geom::CubicBezier> sub1 = bzr1.subdivide(cross[0].ta); + std::pair<Geom::CubicBezier, Geom::CubicBezier> sub2 = bzr2.subdivide(cross[0].tb); + pb.curveTo(sub1.first[1], sub1.first[2], sub1.first[3]); + pb.curveTo(sub2.second[1], sub2.second[2], sub2.second[3]); + } + } + break; + } + case LINEJOIN_EXTRP_MITER_ARC: { + // Extrapolate using the curvature at the end of the path segments to join + Geom::Circle circle1 = Geom::touching_circle(reverse(B[prev_i]), 0.0); + Geom::Circle circle2 = Geom::touching_circle(B[i], 0.0); + std::vector<Geom::ShapeIntersection> solutions; + solutions = circle1.intersect(circle2); + if (solutions.size() == 2) { + Geom::Point sol(0.,0.); + bool solok = true; + bool point0bad = false; + bool point1bad = false; + if ( dot(tang2, solutions[0].point() - B[i].at0()) > 0) + { + // points[0] is bad, choose points[1] + point0bad = true; + } + if ( dot(tang2, solutions[1].point() - B[i].at0()) > 0) + { + // points[1] is bad, choose points[0] + point1bad = true; + } + if (!point0bad && !point1bad ) { + // both points are good, choose nearest + sol = ( distanceSq(B[i].at0(), solutions[0].point()) < distanceSq(B[i].at0(), solutions[1].point()) ) ? + solutions[0].point() : solutions[1].point(); + } else if (!point0bad) { + sol = solutions[0].point(); + } else if (!point1bad) { + sol = solutions[1].point(); + } else { + solok = false; + } + (*bbox).expandBy (bbox->width()/4); + + if (!(*bbox).contains(sol)) { + solok = false; + } + Geom::EllipticalArc *arc0 = nullptr; + Geom::EllipticalArc *arc1 = nullptr; + bool build = false; + if (solok) { + arc0 = circle1.arc(B[prev_i].at1(), 0.5*(B[prev_i].at1()+sol), sol); + arc1 = circle2.arc(sol, 0.5*(sol+B[i].at0()), B[i].at0()); + if (arc0) { + // FIX: Some assertions errors here + build_from_sbasis(pb,arc0->toSBasis(), tol, false); + build = true; + } else if (arc1) { + std::optional<Geom::Point> p = intersection_point( B[prev_i].at1(), tang1, + B[i].at0(), tang2 ); + if (p) { + // check size of miter + Geom::Point point_on_path = B[prev_i].at1() - rot90(tang1) * width; + Geom::Coord len = distance(*p, point_on_path); + if (len <= fabs(width) * miter_limit) { + // miter OK + pb.lineTo(*p); + build = true; + } + } + } + if (build) { + build_from_sbasis(pb,arc1->toSBasis(), tol, false); + } else if (arc0) { + pb.lineTo(B[i].at0()); + } + } + if (!solok || !(arc0 && build)) { + // fall back to miter + std::optional<Geom::Point> p = intersection_point( B[prev_i].at1(), tang1, + B[i].at0(), tang2 ); + if (p) { + // check size of miter + Geom::Point point_on_path = B[prev_i].at1() - rot90(tang1) * width; + Geom::Coord len = distance(*p, point_on_path); + if (len <= fabs(width) * miter_limit) { + // miter OK + pb.lineTo(*p); + } + } + pb.lineTo(B[i].at0()); + } + if (arc0) { + delete arc0; + arc0 = nullptr; + } + if (arc1) { + delete arc1; + arc1 = nullptr; + } + } else { + // fall back to miter + std::optional<Geom::Point> p = intersection_point( B[prev_i].at1(), tang1, + B[i].at0(), tang2 ); + if (p) { + // check size of miter + Geom::Point point_on_path = B[prev_i].at1() - rot90(tang1) * width; + Geom::Coord len = distance(*p, point_on_path); + if (len <= fabs(width) * miter_limit) { + // miter OK + pb.lineTo(*p); + } + } + pb.lineTo(B[i].at0()); + } + /*else if (solutions == 1) { // one circle is inside the other + // don't know what to do: default to bevel + pb.lineTo(B[i].at0()); + } else { // no intersections + // don't know what to do: default to bevel + pb.lineTo(B[i].at0()); + } */ + + break; + } + case LINEJOIN_MITER: { + std::optional<Geom::Point> p = intersection_point( B[prev_i].at1(), tang1, + B[i].at0(), tang2 ); + if (p) { + // check size of miter + Geom::Point point_on_path = B[prev_i].at1() - rot90(tang1) * width; + Geom::Coord len = distance(*p, point_on_path); + if (len <= fabs(width) * miter_limit) { + // miter OK + pb.lineTo(*p); + } + } + pb.lineTo(B[i].at0()); + break; + } + case LINEJOIN_SPIRO: { + Geom::Point direction = B[i].at0() - B[prev_i].at1(); + double tang1_sign = dot(direction,tang1); + double tang2_sign = dot(direction,tang2); + + Spiro::spiro_cp *controlpoints = g_new (Spiro::spiro_cp, 4); + controlpoints[0].x = (B[prev_i].at1() - tang1_sign*tang1)[Geom::X]; + controlpoints[0].y = (B[prev_i].at1() - tang1_sign*tang1)[Geom::Y]; + controlpoints[0].ty = '{'; + controlpoints[1].x = B[prev_i].at1()[Geom::X]; + controlpoints[1].y = B[prev_i].at1()[Geom::Y]; + controlpoints[1].ty = ']'; + controlpoints[2].x = B[i].at0()[Geom::X]; + controlpoints[2].y = B[i].at0()[Geom::Y]; + controlpoints[2].ty = '['; + controlpoints[3].x = (B[i].at0() + tang2_sign*tang2)[Geom::X]; + controlpoints[3].y = (B[i].at0() + tang2_sign*tang2)[Geom::Y]; + controlpoints[3].ty = '}'; + + Geom::Path spiro; + Spiro::spiro_run(controlpoints, 4, spiro); + pb.append(spiro.portion(1, spiro.size_open() - 1)); + break; + } + case LINEJOIN_BEVEL: + default: + pb.lineTo(B[i].at0()); + break; + } + + build_from_sbasis(pb, B[i], tol, false); + + } else { + // we are on inside of corner! + Geom::Path bzr1 = path_from_sbasis( B[prev_i], tol ); + Geom::Path bzr2 = path_from_sbasis( B[i], tol ); + Geom::Crossings cross = crossings(bzr1, bzr2); + if (cross.size() != 1) { + // empty crossing or too many crossings: default to bevel + pb.lineTo(B[i].at0()); + pb.append(bzr2); + } else { + // :-) quick hack: + for (unsigned i=0; i < bzr1.size_open(); ++i) { + pb.backspace(); + } + + pb.append( bzr1.portion(0, cross[0].ta) ); + pb.append( bzr2.portion(cross[0].tb, bzr2.size_open()) ); + } + } + } else { + build_from_sbasis(pb, B[i], tol, false); + } + + prev_i = i; + } + pb.flush(); + return pb.peek().front(); +} + +Geom::PathVector +LPEPowerStroke::doEffect_path (Geom::PathVector const & path_in) +{ + using namespace Geom; + + Geom::PathVector path_out; + if (path_in.empty()) { + return path_in; + } + Geom::PathVector pathv = pathv_to_linear_and_cubic_beziers(path_in); + Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2_in = pathv[0].toPwSb(); + if (pwd2_in.empty()) { + return path_in; + } + Piecewise<D2<SBasis> > der = derivative(pwd2_in); + if (der.empty()) { + return path_in; + } + Piecewise<D2<SBasis> > n = unitVector(der,0.00001); + if (n.empty()) { + return path_in; + } + + n = rot90(n); + offset_points.set_pwd2(pwd2_in, n); + + LineCapType end_linecap = static_cast<LineCapType>(end_linecap_type.get_value()); + LineCapType start_linecap = static_cast<LineCapType>(start_linecap_type.get_value()); + + std::vector<Geom::Point> ts_no_scale = offset_points.data(); + if (ts_no_scale.empty()) { + return path_in; + } + std::vector<Geom::Point> ts; + for (auto & tsp : ts_no_scale) { + Geom::Point p = Geom::Point(tsp[Geom::X], tsp[Geom::Y] * scale_width); + ts.push_back(p); + } + if (sort_points) { + sort(ts.begin(), ts.end(), compare_offsets); + } + // create stroke path where points (x,y) := (t, offset) + Geom::Interpolate::Interpolator *interpolator = Geom::Interpolate::Interpolator::create(static_cast<Geom::Interpolate::InterpolatorType>(interpolator_type.get_value())); + if (Geom::Interpolate::CubicBezierJohan *johan = dynamic_cast<Geom::Interpolate::CubicBezierJohan*>(interpolator)) { + johan->setBeta(interpolator_beta); + } + if (Geom::Interpolate::CubicBezierSmooth *smooth = dynamic_cast<Geom::Interpolate::CubicBezierSmooth*>(interpolator)) { + smooth->setBeta(interpolator_beta); + } + if (pathv[0].closed()) { + std::vector<Geom::Point> ts_close; + //we have only one knot or overwrite before + Geom::Point start = Geom::Point( pwd2_in.domain().min(), ts.front()[Geom::Y]); + Geom::Point end = Geom::Point( pwd2_in.domain().max(), ts.front()[Geom::Y]); + if (ts.size() > 1) { + end = Geom::Point(pwd2_in.domain().max(), 0); + Geom::Point tmpstart(0, 0); + tmpstart[Geom::X] = end[Geom::X] + ts.front()[Geom::X]; + tmpstart[Geom::Y] = ts.front()[Geom::Y]; + ts_close.push_back(ts.back()); + ts_close.push_back(middle_point(tmpstart, ts.back())); + ts_close.push_back(tmpstart); + Geom::Path closepath = interpolator->interpolateToPath(ts_close); + end = closepath.pointAt(Geom::nearest_time(end, closepath)); + end[Geom::X] = pwd2_in.domain().max(); + start = end; + start[Geom::X] = pwd2_in.domain().min(); + } + ts.insert(ts.begin(), start ); + ts.push_back( end ); + ts_close.clear(); + } else { + // add width data for first and last point on the path + // depending on cap type, these first and last points have width zero or take the width from the closest width point. + ts.insert(ts.begin(), Point( pwd2_in.domain().min(), + (start_linecap==LINECAP_ZERO_WIDTH) ? 0. : ts.front()[Geom::Y]) ); + ts.emplace_back( pwd2_in.domain().max(), + (end_linecap==LINECAP_ZERO_WIDTH) ? 0. : ts.back()[Geom::Y] ); + } + + // do the interpolation in a coordinate system that is more alike to the on-canvas knots, + // instead of the heavily compressed coordinate system of (segment_no offset, Y) in which the knots are stored + double pwd2_in_arclength = length(pwd2_in); + double xcoord_scaling = pwd2_in_arclength / ts.back()[Geom::X]; + for (auto & t : ts) { + t[Geom::X] *= xcoord_scaling; + } + + Geom::Path strokepath = interpolator->interpolateToPath(ts); + delete interpolator; + + // apply the inverse knot-xcoord scaling that was applied before the interpolation + strokepath *= Scale(1/xcoord_scaling, 1); + + D2<Piecewise<SBasis> > patternd2 = make_cuts_independent(strokepath.toPwSb()); + Piecewise<SBasis> x = Piecewise<SBasis>(patternd2[0]); + Piecewise<SBasis> y = Piecewise<SBasis>(patternd2[1]); + // find time values for which x lies outside path domain + // and only take portion of x and y that lies within those time values + std::vector< double > rtsmin = roots (x - pwd2_in.domain().min()); + std::vector< double > rtsmax = roots (x + pwd2_in.domain().max()); + if ( !rtsmin.empty() && !rtsmax.empty() ) { + x = portion(x, rtsmin.at(0), rtsmax.at(0)); + y = portion(y, rtsmin.at(0), rtsmax.at(0)); + } + + LineJoinType jointype = static_cast<LineJoinType>(linejoin_type.get_value()); + if (x.empty() || y.empty()) { + return path_in; + } + Piecewise<D2<SBasis> > pwd2_out = compose(pwd2_in,x) + y*compose(n,x); + Piecewise<D2<SBasis> > mirrorpath = reverse( compose(pwd2_in,x) - y*compose(n,x)); + + Geom::Path fixed_path = path_from_piecewise_fix_cusps( pwd2_out, y, jointype, miter_limit, LPE_CONVERSION_TOLERANCE); + Geom::Path fixed_mirrorpath = path_from_piecewise_fix_cusps( mirrorpath, reverse(y), jointype, miter_limit, LPE_CONVERSION_TOLERANCE); + if (pathv[0].closed()) { + fixed_path.close(true); + path_out.push_back(fixed_path); + fixed_mirrorpath.close(true); + path_out.push_back(fixed_mirrorpath); + } else { + // add linecaps... + switch (end_linecap) { + case LINECAP_ZERO_WIDTH: + // do nothing + break; + case LINECAP_PEAK: + { + Geom::Point end_deriv = -unitTangentAt( reverse(pwd2_in.segs.back()), 0.); + double radius = 0.5 * distance(fixed_path.finalPoint(), fixed_mirrorpath.initialPoint()); + Geom::Point midpoint = 0.5*(fixed_path.finalPoint() + fixed_mirrorpath.initialPoint()) + radius*end_deriv; + fixed_path.appendNew<LineSegment>(midpoint); + fixed_path.appendNew<LineSegment>(fixed_mirrorpath.initialPoint()); + break; + } + case LINECAP_SQUARE: + { + Geom::Point end_deriv = -unitTangentAt( reverse(pwd2_in.segs.back()), 0.); + double radius = 0.5 * distance(fixed_path.finalPoint(), fixed_mirrorpath.initialPoint()); + fixed_path.appendNew<LineSegment>( fixed_path.finalPoint() + radius*end_deriv ); + fixed_path.appendNew<LineSegment>( fixed_mirrorpath.initialPoint() + radius*end_deriv ); + fixed_path.appendNew<LineSegment>( fixed_mirrorpath.initialPoint() ); + break; + } + case LINECAP_BUTT: + { + fixed_path.appendNew<LineSegment>( fixed_mirrorpath.initialPoint() ); + break; + } + case LINECAP_ROUND: + default: + { + double radius1 = 0.5 * distance(fixed_path.finalPoint(), fixed_mirrorpath.initialPoint()); + fixed_path.appendNew<EllipticalArc>( radius1, radius1, M_PI/2., false, y.lastValue() < 0, fixed_mirrorpath.initialPoint() ); + break; + } + } + + fixed_path.append(fixed_mirrorpath); + switch (start_linecap) { + case LINECAP_ZERO_WIDTH: + // do nothing + break; + case LINECAP_PEAK: + { + Geom::Point start_deriv = unitTangentAt( pwd2_in.segs.front(), 0.); + double radius = 0.5 * distance(fixed_path.initialPoint(), fixed_mirrorpath.finalPoint()); + Geom::Point midpoint = 0.5*(fixed_mirrorpath.finalPoint() + fixed_path.initialPoint()) - radius*start_deriv; + fixed_path.appendNew<LineSegment>( midpoint ); + fixed_path.appendNew<LineSegment>( fixed_path.initialPoint() ); + break; + } + case LINECAP_SQUARE: + { + Geom::Point start_deriv = unitTangentAt( pwd2_in.segs.front(), 0.); + double radius = 0.5 * distance(fixed_path.initialPoint(), fixed_mirrorpath.finalPoint()); + fixed_path.appendNew<LineSegment>( fixed_mirrorpath.finalPoint() - radius*start_deriv ); + fixed_path.appendNew<LineSegment>( fixed_path.initialPoint() - radius*start_deriv ); + fixed_path.appendNew<LineSegment>( fixed_path.initialPoint() ); + break; + } + case LINECAP_BUTT: + { + fixed_path.appendNew<LineSegment>( fixed_path.initialPoint() ); + break; + } + case LINECAP_ROUND: + default: + { + double radius2 = 0.5 * distance(fixed_path.initialPoint(), fixed_mirrorpath.finalPoint()); + fixed_path.appendNew<EllipticalArc>( radius2, radius2, M_PI/2., false, y.firstValue() < 0, fixed_path.initialPoint() ); + break; + } + } + fixed_path.close(true); + path_out.push_back(fixed_path); + } + if (path_out.empty()) { + return path_in; + // doEffect_path (path_in); + } + return path_out; +} + +void LPEPowerStroke::transform_multiply(Geom::Affine const &postmul, bool /*set*/) +{ + offset_points.param_transform_multiply(postmul, false); +} + +void LPEPowerStroke::doAfterEffect(SPLPEItem const *lpeitem, SPCurve *curve) +{ + if (pathvector_before_effect[0].size() == pathvector_after_effect[0].size()) { + if (recusion_limit < 6) { + Inkscape::LivePathEffect::Effect *effect = + sp_lpe_item->getFirstPathEffectOfType(Inkscape::LivePathEffect::SIMPLIFY); + if (effect) { + LivePathEffect::LPESimplify *simplify = + dynamic_cast<LivePathEffect::LPESimplify *>(effect->getLPEObj()->get_lpe()); + double threshold = simplify->threshold * 1.2; + simplify->threshold.param_set_value(threshold); + simplify->threshold.write_to_SVG(); + has_recursion = true; + } + } + ++recusion_limit; + } else { + recusion_limit = 0; + } +} + +/* ######################## */ + +} //namespace LivePathEffect +} /* namespace Inkscape */ + +/* + 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 : |