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
  16 // You might need to include other 2geom files. You can add them here:
  17 #include <2geom/path.h>
  18 #include <2geom/sbasis.h>
  19 #include <2geom/sbasis-geometric.h>
  20 #include <2geom/bezier-to-sbasis.h>
  21 #include <2geom/sbasis-to-bezier.h>
  22 #include <2geom/d2.h>
  23 #include <2geom/sbasis-math.h>
  24 #include <2geom/piecewise.h>
  25 #include <2geom/crossing.h>
  26 #include <2geom/path-intersection.h>
  27
  28 namespace Inkscape {
  29 namespace LivePathEffect {
  30
  31 LPESketch::LPESketch(LivePathEffectObject *lpeobject) :
  32     Effect(lpeobject),
  33     // initialise your parameters here:
  34     //testpointA(_("Test Point A"), _("Test A"), "ptA", &wr, this, Geom::Point(100,100)),
  35     nbiter_approxstrokes(_("Strokes"), _("Draw that many approximating strokes"), "nbiter_approxstrokes", &wr, this, 5),
  36     strokelength(_("Max stroke length"),
  37                  _("Maximum length of approximating strokes"), "strokelength", &wr, this, 100.),
  38     strokelength_rdm(_("Stroke length variation"),
  39                      _("Random variation of stroke length (relative to maximum length)"), "strokelength_rdm", &wr, this, .3),
  40     strokeoverlap(_("Max. overlap"),
  41                   _("How much successive strokes should overlap (relative to maximum length)"), "strokeoverlap", &wr, this, .3),
  42     strokeoverlap_rdm(_("Overlap variation"),
  43                       _("Random variation of overlap (relative to maximum overlap)"), "strokeoverlap_rdm", &wr, this, .3),
  44     ends_tolerance(_("Max. end tolerance"),
  45                    _("Maximum distance between ends of original and approximating paths (relative to maximum length)"), "ends_tolerance", &wr, this, .1),
  46     parallel_offset(_("Parallel offset"),
  47                     _("Average distance from approximating path to original path"), "parallel_offset", &wr, this, 5.),
  48     tremble_size(_("Max. tremble"),
  49                  _("Maximum tremble magnitude"), "tremble_size", &wr, this, 5.),
  50     tremble_frequency(_("Tremble frequency"),
  51                       _("Average number of tremble periods in an approximating stroke"), "tremble_frequency", &wr, this, 1.),
  52     nbtangents(_("Construction lines"),
  53                _("How many construction lines (tangents) to draw"), "nbtangents", &wr, this, 5),
  54     tgtscale(_("Scale"),
  55              _("Scale factor relating curvature and length of construction lines (try 5*offset)"), "tgtscale", &wr, this, 10.0),
  56     tgtlength(_("Max. length"), _("Maximum length of construction lines"), "tgtlength", &wr, this, 100.0),
  57     tgtlength_rdm(_("Length variation"), _("Random variation of the length of construction lines"), "tgtlength_rdm", &wr, this, .3)
  58 {
  59     // register all your parameters here, so Inkscape knows which parameters this effect has:
  60     //Add some comment in the UI:  *warning* the precise output of this effect might change in future releases!
  61     //convert to path if you want to keep exact output unchanged in future releases...
  62     //registerParameter( dynamic_cast<Parameter *>(&testpointA) );
  63     registerParameter( dynamic_cast<Parameter *>(&nbiter_approxstrokes) );
  64     registerParameter( dynamic_cast<Parameter *>(&strokelength) );
  65     registerParameter( dynamic_cast<Parameter *>(&strokelength_rdm) );
  66     registerParameter( dynamic_cast<Parameter *>(&strokeoverlap) );
  67     registerParameter( dynamic_cast<Parameter *>(&strokeoverlap_rdm) );
  68     registerParameter( dynamic_cast<Parameter *>(&ends_tolerance) );
  69     registerParameter( dynamic_cast<Parameter *>(&parallel_offset) );
  70     registerParameter( dynamic_cast<Parameter *>(&tremble_size) );
  71     registerParameter( dynamic_cast<Parameter *>(&tremble_frequency) );
  72     registerParameter( dynamic_cast<Parameter *>(&nbtangents) );
  73     registerParameter( dynamic_cast<Parameter *>(&tgtscale) );
  74     registerParameter( dynamic_cast<Parameter *>(&tgtlength) );
  75     registerParameter( dynamic_cast<Parameter *>(&tgtlength_rdm) );
  76
  77
  78     nbiter_approxstrokes.param_make_integer();
  79     nbiter_approxstrokes.param_set_range(0, NR_HUGE);
  80     strokelength.param_set_range(1, NR_HUGE);
  81     strokelength.param_set_increments(1., 5.);
  82     strokelength_rdm.param_set_range(0, 1.);
  83     strokeoverlap.param_set_range(0, 1.);
  84     strokeoverlap.param_set_increments(0.1, 0.30);
  85     ends_tolerance.param_set_range(0., 1.);
  86     parallel_offset.param_set_range(0, NR_HUGE);
  87     tremble_frequency.param_set_range(0.01, 100.);
  88     tremble_frequency.param_set_increments(.5, 1.5);
  89     strokeoverlap_rdm.param_set_range(0, 1.);
  90
  91     nbtangents.param_make_integer();
  92     nbtangents.param_set_range(0, NR_HUGE);
  93     tgtscale.param_set_range(0, NR_HUGE);
  94     tgtscale.param_set_increments(.1, .5);
  95     tgtlength.param_set_range(0, NR_HUGE);
  96     tgtlength.param_set_increments(1., 5.);
  97     tgtlength_rdm.param_set_range(0, 1.);
  98 }
  99
 100 LPESketch::~LPESketch()
 101 {
 102
 103 }
 104
 105 /*
 106 Geom::Piecewise<Geom::D2<Geom::SBasis> >
 107 addLinearEnds (Geom::Piecewise<Geom::D2<Geom::SBasis> > & m){
 108     using namespace Geom;
 109     Piecewise<D2<SBasis> > output;
 110     Piecewise<D2<SBasis> > start;
 111     Piecewise<D2<SBasis> > end;
 112     double x,y,vx,vy;
 113
 114     x  = m.segs.front()[0].at0();
 115     y  = m.segs.front()[1].at0();
 116     vx = m.segs.front()[0][1][0]+Tri(m.segs.front()[0][0]);
 117     vy = m.segs.front()[1][1][0]+Tri(m.segs.front()[1][0]);
 118     start = Piecewise<D2<SBasis> >(D2<SBasis>(Linear (x-vx,x),Linear (y-vy,y)));
 119     start.offsetDomain(m.cuts.front()-1.);
 120
 121     x  = m.segs.back()[0].at1();
 122     y  = m.segs.back()[1].at1();
 123     vx = -m.segs.back()[0][1][1]+Tri(m.segs.back()[0][0]);;
 124     vy = -m.segs.back()[1][1][1]+Tri(m.segs.back()[1][0]);;
 125     end = Piecewise<D2<SBasis> >(D2<SBasis>(Linear (x,x+vx),Linear (y,y+vy)));
 126     //end.offsetDomain(m.cuts.back());
 127
 128     output = start;
 129     output.concat(m);
 130     output.concat(end);
 131     return output;
 132 }
 133 */
 134
 135
 136
 137 //This returns a random perturbation. Notice the domain is [s0,s0+first multiple of period>s1]...
 138 Geom::Piecewise<Geom::D2<Geom::SBasis> >
 139 LPESketch::computePerturbation (double s0, double s1){
 140     using namespace Geom;
 141     Piecewise<D2<SBasis> >res;
 142
 143     //global offset for this stroke.
 144     double offsetX = parallel_offset-parallel_offset.get_value();
 145     double offsetY = parallel_offset-parallel_offset.get_value();
 146     Point A,dA,B,dB,offset = Point(offsetX,offsetY);
 147     //start point A
 148     for (unsigned dim=0; dim<2; dim++){
 149         A[dim]  = offset[dim] + 2*tremble_size-tremble_size.get_value();
 150         dA[dim] = 2*tremble_size-tremble_size.get_value();
 151     }
 152     //compute howmany deg 3 sbasis to concat according to frequency.
 153     unsigned count = unsigned((s1-s0)/strokelength*tremble_frequency)+1;
 154     for (unsigned i=0; i<count; i++){
 155         D2<SBasis> perturb = D2<SBasis>();
 156         for (unsigned dim=0; dim<2; dim++){
 157             B[dim] = offset[dim] + 2*tremble_size-tremble_size.get_value();
 158             perturb[dim].push_back(Linear(A[dim],B[dim]));
 159             dA[dim] = dA[dim]-B[dim]+A[dim];
 160             dB[dim] = 2*tremble_size-tremble_size.get_value();
 161             perturb[dim].push_back(Linear(dA[dim],dB[dim]));
 162         }
 163         A = B;
 164         dA = B-A-dB;
 165         res.concat(Piecewise<D2<SBasis> >(perturb));
 166     }
 167     res.setDomain(Interval(s0,s0+count*strokelength/tremble_frequency));
 168     return res;
 169 }
 170
 171
 172 // Main effect body...
 173 Geom::Piecewise<Geom::D2<Geom::SBasis> >
 174 LPESketch::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
 175 {
 176     using namespace Geom;
 177     //If the input path is empty, do nothing.
 178     //Note: this happens when duplicating a 3d box... dunno why.
 179     if (pwd2_in.size()==0) return pwd2_in;
 180
 181     Piecewise<D2<SBasis> > output;
 182
 183
 184     //init random parameters.
 185     parallel_offset.resetRandomizer();
 186     strokelength_rdm.resetRandomizer();
 187     strokeoverlap_rdm.resetRandomizer();
 188     ends_tolerance.resetRandomizer();
 189     tremble_size.resetRandomizer();
 190     tgtlength_rdm.resetRandomizer();
 191
 192
 193
 194     // some variables for futur use (for construction lines; compute arclength only once...)
 195     // notations will be : t = path time, s = distance from start along the path.
 196     Piecewise<SBasis> pathlength;
 197     double total_length = 0;
 198
 199     //TODO: split Construction Lines/Approximated Strokes into two separate effects?
 200
 201     //----- Approximated Strokes.
 202     std::vector<Piecewise<D2<SBasis> > > pieces_in = split_at_discontinuities (pwd2_in);
 203
 204     //work separately on each component.
 205     for (unsigned pieceidx = 0; pieceidx < pieces_in.size(); pieceidx++){
 206
 207         Piecewise<D2<SBasis> > piece = pieces_in[pieceidx];
 208         Piecewise<SBasis> piecelength = arcLengthSb(piece,.1);
 209         double piece_total_length = piecelength.segs.back().at1()-piecelength.segs.front().at0();
 210         pathlength.concat(piecelength + total_length);
 211         total_length += piece_total_length;
 212
 213
 214         //TODO: better check this on the Geom::Path.
 215         bool closed = piece.segs.front().at0() == piece.segs.back().at1();
 216         if (closed){
 217             piece.concat(piece);
 218             piecelength.concat(piecelength+piece_total_length);
 219         }
 220
 221         for (unsigned i = 0; i<nbiter_approxstrokes; i++){
 222             //Basic steps:
 223             //- Choose a rdm seg [s0,s1], find coresponding [t0,t1],
 224             //- Pick a rdm perturbation delta(s), collect 'piece(t)+delta(s(t))' over [t0,t1] into output.
 225
 226             // pick a point where to start the stroke (s0 = dist from start).
 227             double s1=0.,s0 = ends_tolerance*strokelength+0.0001;//the root finder might miss 0.
 228             double t1, t0;
 229             double s0_initial = s0;
 230             bool done = false;// was the end of the component reached?
 231
 232             while (!done){
 233                 // if the start point is already too far... do nothing. (this should not happen!)
 234                 if (!closed && s1>piece_total_length - ends_tolerance.get_value()*strokelength) break;
 235                 if ( closed && s0>piece_total_length + s0_initial) break;
 236
 237                 std::vector<double> times;
 238                 times = roots(piecelength-s0);
 239                 t0 = times.at(0);//there should be one and only one solution!!
 240
 241                 // pick a new end point (s1 = s0 + strokelength).
 242                 s1 = s0 + strokelength*(1-strokelength_rdm);
 243                 // don't let it go beyond the end of the orgiginal path.
 244                 // TODO/FIXME: this might result in short strokes near the end...
 245                 if (!closed && s1>piece_total_length-ends_tolerance.get_value()*strokelength){
 246                     done = true;
 247                     //!!the root solver might miss s1==piece_total_length...
 248                     if (s1>piece_total_length){s1 = piece_total_length - ends_tolerance*strokelength-0.0001;}
 249                 }
 250                 if (closed && s1>piece_total_length + s0_initial){
 251                     done = true;
 252                     if (closed && s1>2*piece_total_length){
 253                         s1 = 2*piece_total_length - strokeoverlap*(1-strokeoverlap_rdm)*strokelength-0.0001;
 254                     }
 255                 }
 256                 times = roots(piecelength-s1);
 257                 if (times.size()==0) break;//we should not be there.
 258                 t1 = times[0];
 259
 260                 //pick a rdm perturbation, and collect the perturbed piece into output.
 261                 Piecewise<D2<SBasis> > pwperturb = computePerturbation(s0,s1);
 262                 pwperturb = compose(pwperturb,portion(piecelength,t0,t1));
 263                 output.concat(portion(piece,t0,t1)+pwperturb);
 264
 265                 //step points: s0 = s1 - overlap.
 266                 //TODO: make sure this has to end?
 267                 s0 = s1 - strokeoverlap*(1-strokeoverlap_rdm)*(s1-s0);
 268             }
 269         }
 270     }
 271
 272
 273     //----- Construction lines.
 274     //TODO: choose places according to curvature?.
 275
 276     //at this point we should have:
 277     //pathlength = arcLengthSb(pwd2_in,.1);
 278     //total_length = pathlength.segs.back().at1()-pathlength.segs.front().at0();
 279     Piecewise<D2<SBasis> > m = pwd2_in;
 280     Piecewise<D2<SBasis> > v = derivative(pwd2_in);
 281     Piecewise<D2<SBasis> > a = derivative(v);
 282     for (unsigned i=0; i<nbtangents; i++){
 283         // pick a point where to draw a tangent (s = dist from start along path).
 284         double s = total_length * ( i + tgtlength_rdm ) / (nbtangents+1.);
 285         std::vector<double> times;
 286         times = roots(pathlength-s);
 287         double t = times.at(0);//there should be one and only one solution!
 288         Point m_t = m(t), v_t = v(t), a_t = a(t);
 289         //Compute tgt length according to curvature (not exceeding tgtlength) so that
 290         //  dist to origninal curve ~ 4 * (parallel_offset+tremble_size).
 291         //TODO: put this 4 as a parameter in the UI...
 292         //TODO: what if with v=0?
 293         double l = tgtlength*(1-tgtlength_rdm)/v_t.length();
 294         double r = pow(v_t.length(),3)/cross(a_t,v_t);
 295         r = sqrt((2*fabs(r)-tgtscale)*tgtscale)/v_t.length();
 296         l=(r<l)?r:l;
 297         //collect the tgt segment into output.
 298         D2<SBasis> tgt = D2<SBasis>();
 299         for (unsigned dim=0; dim<2; dim++){
 300             tgt[dim] = SBasis(Linear(m_t[dim]-v_t[dim]*l, m_t[dim]+v_t[dim]*l));
 301         }
 302         output.concat(Piecewise<D2<SBasis> >(tgt));
 303     }
 304     return output;
 305 }
 306
 307 /* ######################## */
 308
 309 } //namespace LivePathEffect (setq default-directory "c:/Documents And Settings/jf/Mes Documents/InkscapeSVN")
 310 } /* namespace Inkscape */
 311
 312 /*
 313   Local Variables:
 314   mode:c++
 315   c-file-style:"stroustrup"
 316   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 317   indent-tabs-mode:nil
 318   fill-column:99
 319   End:
 320 */
 321 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :