src/live_effects/lpe-sketch.cpp

   1 #define INKSCAPE_LPE_SKETCH_CPP
   2 /** \file
   3  * LPE <sketch> implementation
   4  */
   5 /*
   6  * Authors:
   7  *   Johan Engelen
   8 *
   9 * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
  10  *
  11  * Released under GNU GPL, read the file 'COPYING' for more information
  12  */
  13
  14 #include "live_effects/lpe-sketch.h"
  15 #include "display/curve.h"
  16 #include <libnr/n-art-bpath.h>
  17
  18 // You might need to include other 2geom files. You can add them here:
  19 #include <2geom/path.h>
  20 #include <2geom/sbasis.h>
  21 #include <2geom/sbasis-geometric.h>
  22 #include <2geom/bezier-to-sbasis.h>
  23 #include <2geom/sbasis-to-bezier.h>
  24 #include <2geom/d2.h>
  25 #include <2geom/sbasis-math.h>
  26 #include <2geom/piecewise.h>
  27 #include <2geom/crossing.h>
  28 #include <2geom/path-intersection.h>
  29
  30 namespace Inkscape {
  31 namespace LivePathEffect {
  32
  33 LPESketch::LPESketch(LivePathEffectObject *lpeobject) :
  34     Effect(lpeobject),
  35     // initialise your parameters here:
  36     //testpointA(_("Test Point A"), _("Test A"), "ptA", &wr, this, Geom::Point(100,100)),
  37     nbiter_approxstrokes(_("Strokes"), _("Draw that many approximating strokes"), "nbiter_approxstrokes", &wr, this, 5),
  38     strokelength(_("Max stroke length"),
  39                  _("Maximum length of approximating strokes"), "strokelength", &wr, this, 100.),
  40     strokelength_rdm(_("Stroke length variation"),
  41                      _("Random variation of stroke length (relative to maximum length)"), "strokelength_rdm", &wr, this, .3),
  42     strokeoverlap(_("Max. overlap"),
  43                   _("How much successive strokes should overlap (relative to maximum length)."), "strokeoverlap", &wr, this, .3),
  44     strokeoverlap_rdm(_("Overlap variation"),
  45                       _("Random variation of overlap (relative to maximum overlap)"), "strokeoverlap_rdm", &wr, this, .3),
  46     ends_tolerance(_("Max. end tolerance"),
  47                    _("Maximum distance between ends of original and approximating paths (relative to maximum length)"), "ends_tolerance", &wr, this, .1),
  48     parallel_offset(_("Parallel offset"),
  49                     _("Average distance from approximating path to original path"), "parallel_offset", &wr, this, 5.),
  50     tremble_size(_("Max. tremble"),
  51                  _("Maximum tremble magnitude"), "tremble_size", &wr, this, 5.),
  52     tremble_frequency(_("Tremble frequency"),
  53                       _("Avreage number of tremble periods in an approximating stroke"), "tremble_frequency", &wr, this, 1.),
  54     nbtangents(_("Construction lines"),
  55                _("How many construction lines (tangents) to draw"), "nbtangents", &wr, this, 5),
  56     tgtscale(_("Scale"),
  57              _("Scale factor relating curvature and length of construction lines (try 5*offset)"), "tgtscale", &wr, this, 10.0),
  58     tgtlength(_("Max. length"), _("Maximum length of construction lines"), "tgtlength", &wr, this, 100.0),
  59     tgtlength_rdm(_("Length variation"), _("Random variation of the length of construction lines"), "tgtlength_rdm", &wr, this, .3)
  60 {
  61     // register all your parameters here, so Inkscape knows which parameters this effect has:
  62     //Add some comment in the UI:  *warning* the precise output of this effect might change in future releases!
  63     //convert to path if you want to keep exact output unchanged in future releases...
  64     //registerParameter( dynamic_cast<Parameter *>(&testpointA) );
  65     registerParameter( dynamic_cast<Parameter *>(&nbiter_approxstrokes) );
  66     registerParameter( dynamic_cast<Parameter *>(&strokelength) );
  67     registerParameter( dynamic_cast<Parameter *>(&strokelength_rdm) );
  68     registerParameter( dynamic_cast<Parameter *>(&strokeoverlap) );
  69     registerParameter( dynamic_cast<Parameter *>(&strokeoverlap_rdm) );
  70     registerParameter( dynamic_cast<Parameter *>(&ends_tolerance) );
  71     registerParameter( dynamic_cast<Parameter *>(&parallel_offset) );
  72     registerParameter( dynamic_cast<Parameter *>(&tremble_size) );
  73     registerParameter( dynamic_cast<Parameter *>(&tremble_frequency) );
  74     registerParameter( dynamic_cast<Parameter *>(&nbtangents) );
  75     registerParameter( dynamic_cast<Parameter *>(&tgtscale) );
  76     registerParameter( dynamic_cast<Parameter *>(&tgtlength) );
  77     registerParameter( dynamic_cast<Parameter *>(&tgtlength_rdm) );
  78
  79
  80     nbiter_approxstrokes.param_make_integer();
  81     nbiter_approxstrokes.param_set_range(0, NR_HUGE);
  82     strokelength.param_set_range(1, NR_HUGE);
  83     strokelength.param_set_increments(1., 5.);
  84     strokelength_rdm.param_set_range(0, 1.);
  85     strokeoverlap.param_set_range(0, 1.);
  86     strokeoverlap.param_set_increments(0.1, 0.30);
  87     ends_tolerance.param_set_range(0., 1.);
  88     parallel_offset.param_set_range(0, NR_HUGE);
  89     tremble_frequency.param_set_range(0.01, 100.);
  90     tremble_frequency.param_set_increments(.5, 1.5);
  91     strokeoverlap_rdm.param_set_range(0, 1.);
  92
  93     nbtangents.param_make_integer();
  94     nbtangents.param_set_range(0, NR_HUGE);
  95     tgtscale.param_set_range(0, NR_HUGE);
  96     tgtscale.param_set_increments(.1, .5);
  97     tgtlength.param_set_range(0, NR_HUGE);
  98     tgtlength.param_set_increments(1., 5.);
  99     tgtlength_rdm.param_set_range(0, 1.);
 100 }
 101
 102 LPESketch::~LPESketch()
 103 {
 104
 105 }
 106
 107 /*
 108 Geom::Piecewise<Geom::D2<Geom::SBasis> >
 109 addLinearEnds (Geom::Piecewise<Geom::D2<Geom::SBasis> > & m){
 110     using namespace Geom;
 111     Piecewise<D2<SBasis> > output;
 112     Piecewise<D2<SBasis> > start;
 113     Piecewise<D2<SBasis> > end;
 114     double x,y,vx,vy;
 115
 116     x  = m.segs.front()[0].at0();
 117     y  = m.segs.front()[1].at0();
 118     vx = m.segs.front()[0][1][0]+Tri(m.segs.front()[0][0]);
 119     vy = m.segs.front()[1][1][0]+Tri(m.segs.front()[1][0]);
 120     start = Piecewise<D2<SBasis> >(D2<SBasis>(Linear (x-vx,x),Linear (y-vy,y)));
 121     start.offsetDomain(m.cuts.front()-1.);
 122
 123     x  = m.segs.back()[0].at1();
 124     y  = m.segs.back()[1].at1();
 125     vx = -m.segs.back()[0][1][1]+Tri(m.segs.back()[0][0]);;
 126     vy = -m.segs.back()[1][1][1]+Tri(m.segs.back()[1][0]);;
 127     end = Piecewise<D2<SBasis> >(D2<SBasis>(Linear (x,x+vx),Linear (y,y+vy)));
 128     //end.offsetDomain(m.cuts.back());
 129
 130     output = start;
 131     output.concat(m);
 132     output.concat(end);
 133     return output;
 134 }
 135 */
 136
 137
 138
 139 //This returns a random perturbation. Notice the domain is [s0,s0+first multiple of period>s1]...
 140 Geom::Piecewise<Geom::D2<Geom::SBasis> >
 141 LPESketch::computePerturbation (double s0, double s1){
 142     using namespace Geom;
 143     Piecewise<D2<SBasis> >res;
 144
 145     //global offset for this stroke.
 146     double offsetX = parallel_offset-parallel_offset.get_value();
 147     double offsetY = parallel_offset-parallel_offset.get_value();
 148     Point A,dA,B,dB,offset = Point(offsetX,offsetY);
 149     //start point A
 150     for (unsigned dim=0; dim<2; dim++){
 151         A[dim]  = offset[dim] + 2*tremble_size-tremble_size.get_value();
 152         dA[dim] = 2*tremble_size-tremble_size.get_value();
 153     }
 154     //compute howmany deg 3 sbasis to concat according to frequency.
 155     unsigned count = unsigned((s1-s0)/strokelength*tremble_frequency)+1;
 156     for (unsigned i=0; i<count; i++){
 157         D2<SBasis> perturb = D2<SBasis>();
 158         for (unsigned dim=0; dim<2; dim++){
 159             B[dim] = offset[dim] + 2*tremble_size-tremble_size.get_value();
 160             perturb[dim].push_back(Linear(A[dim],B[dim]));
 161             dA[dim] = dA[dim]-B[dim]+A[dim];
 162             dB[dim] = 2*tremble_size-tremble_size.get_value();
 163             perturb[dim].push_back(Linear(dA[dim],dB[dim]));
 164         }
 165         A = B;
 166         dA = B-A-dB;
 167         res.concat(Piecewise<D2<SBasis> >(perturb));
 168     }
 169     res.setDomain(Interval(s0,s0+count*strokelength/tremble_frequency));
 170     return res;
 171 }
 172
 173
 174 // Main effect body...
 175 Geom::Piecewise<Geom::D2<Geom::SBasis> >
 176 LPESketch::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
 177 {
 178     using namespace Geom;
 179     //If the input path is empty, do nothing.
 180     //Note: this happens when duplicating a 3d box... dunno why.
 181     if (pwd2_in.size()==0) return pwd2_in;
 182
 183     Piecewise<D2<SBasis> > output;
 184
 185
 186     //init random parameters.
 187     parallel_offset.resetRandomizer();
 188     strokelength_rdm.resetRandomizer();
 189     strokeoverlap_rdm.resetRandomizer();
 190     tgtlength_rdm.resetRandomizer();
 191
 192     // some variables for futur use (for construction lines; compute arclength only once...)
 193     // notations will be : t = path time, s = distance from start along the path.
 194     Piecewise<SBasis> pathlength;
 195     double total_length = 0;
 196
 197     //TODO: split Construction Lines/Approximated Strokes into two separate effects?
 198
 199     //----- Approximated Strokes.
 200     std::vector<Piecewise<D2<SBasis> > > pieces_in = split_at_discontinuities (pwd2_in);
 201
 202     //work separately on each component.
 203     for (unsigned pieceidx = 0; pieceidx < pieces_in.size(); pieceidx++){
 204
 205         Piecewise<D2<SBasis> > piece = pieces_in[pieceidx];
 206         Piecewise<SBasis> piecelength = arcLengthSb(piece,.1);
 207         double piece_total_length = piecelength.segs.back().at1()-piecelength.segs.front().at0();
 208         pathlength.concat(piecelength + total_length);
 209         total_length += piece_total_length;
 210
 211
 212         //TODO: better check this on the Geom::Path.
 213         bool closed = piece.segs.front().at0() == piece.segs.back().at1();
 214         if (closed){
 215             piece.concat(piece);
 216             piecelength.concat(piecelength+piece_total_length);
 217         }
 218
 219         for (unsigned i = 0; i<nbiter_approxstrokes; i++){
 220             //Basic steps:
 221             //- Choose a rdm seg [s0,s1], find coresponding [t0,t1],
 222             //- Pick a rdm perturbation delta(s), collect 'piece(t)+delta(s(t))' over [t0,t1] into output.
 223
 224             // pick a point where to start the stroke (s0 = dist from start).
 225             double s1=0.,s0 = ends_tolerance*strokelength+0.0001;//the root finder might miss 0.
 226             double t1, t0;
 227             double s0_initial = s0;
 228             bool done = false;// was the end of the component reached?
 229
 230             while (!done){
 231                 // if the start point is already too far... do nothing. (this should not happen!)
 232                 if (!closed && s1>piece_total_length - ends_tolerance.get_value()*strokelength) break;
 233                 if ( closed && s0>piece_total_length + s0_initial) break;
 234
 235                 std::vector<double> times;
 236                 times = roots(piecelength-s0);
 237                 t0 = times.at(0);//there should be one and only one solution!!
 238
 239                 // pick a new end point (s1 = s0 + strokelength).
 240                 s1 = s0 + strokelength*(1-strokelength_rdm);
 241                 // don't let it go beyond the end of the orgiginal path.
 242                 // TODO/FIXME: this might result in short strokes near the end...
 243                 if (!closed && s1>piece_total_length-ends_tolerance.get_value()*strokelength){
 244                     done = true;
 245                     //!!the root solver might miss s1==piece_total_length...
 246                     if (s1>piece_total_length){s1 = piece_total_length - ends_tolerance*strokelength-0.0001;}
 247                 }
 248                 if (closed && s1>piece_total_length + s0_initial){
 249                     done = true;
 250                     if (closed && s1>2*piece_total_length){
 251                         s1 = 2*piece_total_length - strokeoverlap*(1-strokeoverlap_rdm)*strokelength-0.0001;
 252                     }
 253                 }
 254                 times = roots(piecelength-s1);
 255                 if (times.size()==0) break;//we should not be there.
 256                 t1 = times[0];
 257
 258                 //pick a rdm perturbation, and collect the perturbed piece into output.
 259                 Piecewise<D2<SBasis> > pwperturb = computePerturbation(s0,s1);
 260                 pwperturb = compose(pwperturb,portion(piecelength,t0,t1));
 261                 output.concat(portion(piece,t0,t1)+pwperturb);
 262
 263                 //step points: s0 = s1 - overlap.
 264                 //TODO: make sure this has to end?
 265                 s0 = s1 - strokeoverlap*(1-strokeoverlap_rdm)*(s1-s0);
 266             }
 267         }
 268     }
 269
 270
 271     //----- Construction lines.
 272     //TODO: choose places according to curvature?.
 273
 274     //at this point we should have:
 275     //pathlength = arcLengthSb(pwd2_in,.1);
 276     //total_length = pathlength.segs.back().at1()-pathlength.segs.front().at0();
 277     Piecewise<D2<SBasis> > m = pwd2_in;
 278     Piecewise<D2<SBasis> > v = derivative(pwd2_in);
 279     Piecewise<D2<SBasis> > a = derivative(v);
 280     for (unsigned i=0; i<nbtangents; i++){
 281         // pick a point where to draw a tangent (s = dist from start along path).
 282         double s = total_length * ( i + tgtlength_rdm ) / (nbtangents+1.);
 283         std::vector<double> times;
 284         times = roots(pathlength-s);
 285         double t = times.at(0);//there should be one and only one solution!
 286         Point m_t = m(t), v_t = v(t), a_t = a(t);
 287         //Compute tgt length according to curvature (not exceeding tgtlength) so that
 288         //  dist to origninal curve ~ 4 * (parallel_offset+tremble_size).
 289         //TODO: put this 4 as a parameter in the UI...
 290         //TODO: what if with v=0?
 291         double l = tgtlength*(1-tgtlength_rdm)/v_t.length();
 292         double r = pow(v_t.length(),3)/cross(a_t,v_t);
 293         r = sqrt((2*fabs(r)-tgtscale)*tgtscale)/v_t.length();
 294         l=(r<l)?r:l;
 295         //collect the tgt segment into output.
 296         D2<SBasis> tgt = D2<SBasis>();
 297         for (unsigned dim=0; dim<2; dim++){
 298             tgt[dim] = SBasis(Linear(m_t[dim]-v_t[dim]*l, m_t[dim]+v_t[dim]*l));
 299         }
 300         output.concat(Piecewise<D2<SBasis> >(tgt));
 301     }
 302     return output;
 303 }
 304
 305 /* ######################## */
 306
 307 } //namespace LivePathEffect (setq default-directory "c:/Documents And Settings/jf/Mes Documents/InkscapeSVN")
 308 } /* namespace Inkscape */
 309
 310 /*
 311   Local Variables:
 312   mode:c++
 313   c-file-style:"stroustrup"
 314   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 315   indent-tabs-mode:nil
 316   fill-column:99
 317   End:
 318 */
 319 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :