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Diffstat (limited to 'src/toys/nearest-times.cpp')
| -rw-r--r-- | src/toys/nearest-times.cpp | 258 |
1 files changed, 258 insertions, 0 deletions
diff --git a/src/toys/nearest-times.cpp b/src/toys/nearest-times.cpp new file mode 100644 index 0000000..66803d6 --- /dev/null +++ b/src/toys/nearest-times.cpp @@ -0,0 +1,258 @@ +/* + * Nearest Points Toy + * + * Authors: + * Nathan Hurst <njh at njhurst.com> + * Marco Cecchetti <mrcekets at gmail.com> + * + * Copyright 2008 authors + * + * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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. + */ + +#include <2geom/d2.h> +#include <2geom/sbasis.h> +#include <2geom/path.h> +#include <2geom/bezier-to-sbasis.h> + +#include <toys/path-cairo.h> +#include <toys/toy-framework.h> + + +using namespace Geom; + + +class np_finder +{ +public: + np_finder(cairo_t* _cr, D2<SBasis> const& _c1, D2<SBasis> const& _c2) + : cr(_cr), c1(_c1), c2(_c2) + { + dc1 = derivative(c1); + dc2 = derivative(c2); + cd1 = dot(c1,dc1); + cd2 = dot(c2,dc2); + dsq = 10e30; + } + + void operator() () + { + nearest_times_impl(0.5, 0, 1); + d = sqrt(dsq); + } + + Point firstPoint() const + { + return p1; + } + + Point secondPoint() const + { + return p2; + } + + double firstValue() const + { + return t1; + } + + double secondValue() const + { + return t2; + } + + double distance() const + { + return d; + } + +private: + void nearest_times_impl( double t, double from = 0, double to = 1 ) + { + //std::cerr << "[" << from << "," << to << "] t: " << t << std::endl; + + double st = t, et = t; + std::pair<double, double> npc = loc_nearest_times(t, from, to); + //std::cerr << "(" << npc.first << "," << npc.second << ")" << std::endl; + if ( npc.second != -1 && dsq > L2sq(c1(npc.first) - c2(npc.second)) ) + { + t1 = npc.first; + t2 = npc.second; + p1 = c1(t1); + p2 = c2(t2); + dsq = L2sq(p1 - p2); + } + if (npc.first < t) + st = npc.first; + else + et = npc.first; + //std::cerr << "[" << st << "," << et << "]" << std::endl; + double d1 = std::fabs(st - from); + double d2 = std::fabs(to - et); + if ( d1 > EPSILON ) + nearest_times_impl(from + d1/2, from, st); + if ( d2 > EPSILON ) + nearest_times_impl(et + d2/2, et, to); + } + + std::pair<double, double> + loc_nearest_times( double t, double from = 0, double to = 1 ) + { + unsigned int i = 0; + std::pair<double, double> np(-1,-1); + std::pair<double, double> npf(from, -1); + std::pair<double, double> npt(to, -1); + double ct = t; + double pt = -1; + double s; + //cairo_set_source_rgba(cr, 1/(t+1), t*t, t, 1.0); + //cairo_move_to(cr, c1(t)); + while( !are_near(ct, pt) ) + { + ++i; + pt = ct; + s = nearest_time(c1(ct), c2, dc2, cd2); + //std::cerr << "s: " << s << std::endl; + //cairo_line_to(cr, c2(s)); + ct = nearest_time(c2(s), c1, dc1, cd1, from, to); + //std::cerr << "t: " << t1 << std::endl; + //cairo_line_to(cr, c1(ct)); + if ( ct < from ) return npf; + if ( ct > to ) return npt; + } + //std::cerr << "\n \n"; + //std::cerr << "iterations: " << i << std::endl; + cairo_stroke(cr); + np.first = ct; + np.second = s; + return np; + } + + double nearest_time( Point const& p, D2<SBasis> const&c, D2<SBasis> const& dc, SBasis const& cd, double from = 0, double to = 1 ) + { + D2<SBasis> sbc = c - p; + SBasis dd = cd - dotp(p, dc); + std::vector<double> zeros = roots(dd); + double closest = from; + double distsq = L2sq(sbc(from)); + for ( unsigned int i = 0; i < zeros.size(); ++i ) + { + if ( distsq > L2sq(sbc(zeros[i])) ) + { + closest = zeros[i]; + distsq = L2sq(sbc(closest)); + } + } + if ( distsq > L2sq(sbc(to)) ) + closest = to; + return closest; + } + + SBasis dotp(Point const& p, D2<SBasis> const& c) + { + SBasis d; + d.resize(c[X].size()); + for ( unsigned int i = 0; i < c[0].size(); ++i ) + { + for( unsigned int j = 0; j < 2; ++j ) + d[i][j] = p[X] * c[X][i][j] + p[Y] * c[Y][i][j]; + } + return d; + } + +private: + static const Coord EPSILON = 10e-3; + cairo_t* cr; + D2<SBasis> const& c1, c2; + D2<SBasis> dc1, dc2; + SBasis cd1, cd2; + double t1, t2, d, dsq; + Point p1, p2; +}; + + + + +class NearestPoints : public Toy +{ + private: + void draw( cairo_t *cr, std::ostringstream *notify, + int width, int height, bool save, std::ostringstream *timer_stream) + { + cairo_set_line_width (cr, 0.2); + D2<SBasis> A = handles_to_sbasis(handles.begin(), A_bez_ord-1); + cairo_d2_sb(cr, A); + D2<SBasis> B = handles_to_sbasis(handles.begin()+A_bez_ord, B_bez_ord-1); + cairo_d2_sb(cr, B); + + + np_finder np(cr, A, B); + np(); + cairo_move_to(cr, np.firstPoint()); + cairo_line_to(cr, np.secondPoint()); + cairo_stroke(cr); + //std::cerr << "np: (" << np.firstValue() << "," << np.secondValue() << ")" << std::endl; + + Toy::draw(cr, notify, width, height, save,timer_stream); + } + + public: + NearestPoints(unsigned int _A_bez_ord, unsigned int _B_bez_ord) + : A_bez_ord(_A_bez_ord), B_bez_ord(_B_bez_ord) + { + unsigned int total_handles = A_bez_ord + B_bez_ord; + for ( unsigned int i = 0; i < total_handles; ++i ) + handles.push_back(Geom::Point(uniform()*400, uniform()*400)); + } + + private: + unsigned int A_bez_ord; + unsigned int B_bez_ord; +}; + + +int main(int argc, char **argv) +{ + unsigned int A_bez_ord=8; + unsigned int B_bez_ord=5; + if(argc > 2) + sscanf(argv[2], "%d", &B_bez_ord); + if(argc > 1) + sscanf(argv[1], "%d", &A_bez_ord); + + init( argc, argv, new NearestPoints(A_bez_ord, B_bez_ord)); + return 0; +} + + +/* + 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 : |