4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen * Interpolators for lists of points.
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen * Johan Engelen <j.b.c.engelen@alumnus.utwente.nl>
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen * Copyright (C) 2010-2011 Authors
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen * Released under GNU GPL, read the file 'COPYING' for more information
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen#ifndef INKSCAPE_LPE_POWERSTROKE_INTERPOLATORS_H
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen#define INKSCAPE_LPE_POWERSTROKE_INTERPOLATORS_H
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen/// @TODO Move this to 2geom?
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen static Interpolator* create(InterpolatorType type);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen virtual Geom::Path interpolateToPath(std::vector<Point> const &points) const = 0;
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen virtual Path interpolateToPath(std::vector<Point> const &points) const {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen for (unsigned int i = 1 ; i < points.size(); ++i) {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen path.appendNew<Geom::LineSegment>(points.at(i));
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen// this class is terrible
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen virtual Path interpolateToPath(std::vector<Point> const &points) const {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen // worst case gives us 2 segment per point
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen Geom::Point * b = g_new(Geom::Point, max_segs);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen Geom::Point * points_array = g_new(Geom::Point, 4*n_points);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen for (unsigned i = 0; i < n_points; ++i) {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen double tolerance_sq = 0; // this value is just a random guess
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen int const n_segs = Geom::bezier_fit_cubic_r(b, points_array, n_points,
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen for (int c = 0; c < n_segs; c++) {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen fit.appendNew<Geom::CubicBezier>(b[4*c+1], b[4*c+2], b[4*c+3]);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen CubicBezierFit& operator=(const CubicBezierFit&);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen/// @todo invent name for this class
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen virtual Path interpolateToPath(std::vector<Point> const &points) const {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen for (unsigned int i = 1; i < points.size(); ++i) {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen fit.appendNew<CubicBezier>(p0+_beta*dx, p1-_beta*dx, p1);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen CubicBezierJohan& operator=(const CubicBezierJohan&);
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White/// @todo invent name for this class
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. Whiteclass CubicBezierSmooth : public Interpolator {
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White virtual Path interpolateToPath(std::vector<Point> const &points) const {
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White for (unsigned int i = 1; i < num_points; ++i) {
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White if (i == 1) {
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White fit.appendNew<CubicBezier>(p0, p1-0.75*dx, p1);
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White fit.appendNew<CubicBezier>(p0+0.75*dx, p1, p1);
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White fit.appendNew<CubicBezier>(p0+_beta*dx, p1-_beta*dx, p1);
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White CubicBezierSmooth& operator=(const CubicBezierSmooth&);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelenclass SpiroInterpolator : public Interpolator {
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen virtual Path interpolateToPath(std::vector<Point> const &points) const {
b49365c42b99e3cc135dcde0077aad31d930f6c1Johan B. C. Engelen Spiro::spiro_cp *controlpoints = g_new (Spiro::spiro_cp, len);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen for (unsigned int i = 0; i < len; ++i) {
b49365c42b99e3cc135dcde0077aad31d930f6c1Johan B. C. Engelen Spiro::spiro_run(controlpoints, len, fit);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen SpiroInterpolator& operator=(const SpiroInterpolator&);
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen// Quick mockup for testing the behavior for powerstroke controlpoint interpolation
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelenclass CentripetalCatmullRomInterpolator : public Interpolator {
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen virtual ~CentripetalCatmullRomInterpolator() {};
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen virtual Path interpolateToPath(std::vector<Point> const &points) const {
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen if (n_points < 3) return fit; // TODO special cases for 0,1 and 2 input points
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // return n_points-1 cubic segments
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // duplicate first point
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen fit.append(calc_bezier(points[0],points[0],points[1],points[2]));
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen for (std::size_t i = 0; i < n_points-2; ++i) {
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen Point p3 = (i < n_points-3) ? points[i+3] : points[i+2];
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen fit.append(calc_bezier(p0, p1, p2, p3));
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen CubicBezier calc_bezier(Point p0, Point p1, Point p2, Point p3) const {
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // create interpolating bezier between p1 and p2
26467da82c920aae52b2c00844c12f9ea236b480Johan B. C. Engelen // Part of the code comes from StackOverflow user eriatarka84
26467da82c920aae52b2c00844c12f9ea236b480Johan B. C. Engelen // http://stackoverflow.com/a/23980479/2929337
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // calculate time coords (deltas) of points
26467da82c920aae52b2c00844c12f9ea236b480Johan B. C. Engelen // the factor 0.25 can be generalized for other Catmull-Rom interpolation types
26467da82c920aae52b2c00844c12f9ea236b480Johan B. C. Engelen // see alpha in Yuksel et al. "On the Parameterization of Catmull-Rom Curves",
26467da82c920aae52b2c00844c12f9ea236b480Johan B. C. Engelen // --> http://www.cemyuksel.com/research/catmullrom_param/catmullrom.pdf
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen double dt0 = powf(distanceSq(p0, p1), 0.25);
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen double dt1 = powf(distanceSq(p1, p2), 0.25);
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen double dt2 = powf(distanceSq(p2, p3), 0.25);
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // safety check for repeated points
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // compute tangents when parameterized in [t1,t2]
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen Point tan1 = (p1 - p0) / dt0 - (p2 - p0) / (dt0 + dt1) + (p2 - p1) / dt1;
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen Point tan2 = (p2 - p1) / dt1 - (p3 - p1) / (dt1 + dt2) + (p3 - p2) / dt2;
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // rescale tangents for parametrization in [0,1]
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // create bezier from tangents (this is already in 2geom somewhere, or should be moved to it)
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // the tangent of a bezier curve is: B'(t) = 3(1-t)^2 (b1 - b0) + 6(1-t)t(b2-b1) + 3t^2(b3-b2)
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // So we have to make sure that B'(0) = tan1 and B'(1) = tan2, and we already know that b0=p1 and b3=p2
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // tan1 = B'(0) = 3 (b1 - p1) --> p1 + (tan1)/3 = b1
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen // tan2 = B'(1) = 3 (p2 - b2) --> p2 - (tan2)/3 = b2
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen CentripetalCatmullRomInterpolator(const CentripetalCatmullRomInterpolator&);
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen CentripetalCatmullRomInterpolator& operator=(const CentripetalCatmullRomInterpolator&);
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen return new Geom::Interpolate::CubicBezierFit();
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen return new Geom::Interpolate::CubicBezierJohan();
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen return new Geom::Interpolate::SpiroInterpolator();
8ba84881e79b6175868d04179ca86f4823a69ec0Liam P. White return new Geom::Interpolate::CubicBezierSmooth();
742a1b08138aef8fc3c19730ae48e5477ee43fc5Johan B. C. Engelen return new Geom::Interpolate::CentripetalCatmullRomInterpolator();
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen} //namespace Interpolate
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen} //namespace Geom
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen Local Variables:
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen c-file-style:"stroustrup"
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen indent-tabs-mode:nil
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4fd537e3c7f3fb1b0013f94688e95b0c3ef6649cJohan Engelen// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:fileencoding=utf-8:textwidth=99 :