src/live_effects/lpe-extrude.cpp

   1 #define INKSCAPE_LPE_EXTRUDE_CPP
   2 /** \file
   3  * @brief LPE effect for extruding paths (making them "3D").
   4  *
   5  */
   6 /* Authors:
   7  *   Johan Engelen <j.b.c.engelen@utwente.nl>
   8  *
   9  * Copyright (C) 2009 Authors
  10  *
  11  * Released under GNU GPL, read the file 'COPYING' for more information
  12  */
  13
  14 #include "live_effects/lpe-extrude.h"
  15
  16 #include <2geom/path.h>
  17 #include <2geom/piecewise.h>
  18 #include <2geom/transforms.h>
  19
  20 namespace Inkscape {
  21 namespace LivePathEffect {
  22
  23 LPEExtrude::LPEExtrude(LivePathEffectObject *lpeobject) :
  24     Effect(lpeobject),
  25     extrude_vector(_("Direction"), _("Defines the direction and magnitude of the extrusion"), "extrude_vector", &wr, this, Geom::Point(-10,10))
  26 {
  27     show_orig_path = true;
  28     concatenate_before_pwd2 = false;
  29
  30     registerParameter( dynamic_cast<Parameter *>(&extrude_vector) );
  31 }
  32
  33 LPEExtrude::~LPEExtrude()
  34 {
  35
  36 }
  37
  38
  39 Geom::Piecewise<Geom::D2<Geom::SBasis> >
  40 LPEExtrude::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
  41 {
  42     using namespace Geom;
  43
  44     // generate connecting lines (the 'sides' of the extrusion)
  45     Path path(Point(0.,0.));
  46     path.appendNew<Geom::LineSegment>( extrude_vector.getVector() );
  47     Piecewise<D2<SBasis> > connector = path.toPwSb();
  48
  49     switch( 1 ) {
  50     case 0: {
  51         Piecewise<D2<SBasis> > pwd2_out = pwd2_in;
  52         // generate extrusion bottom: (just a copy of original path, displaced a bit)
  53         pwd2_out.concat( pwd2_in + extrude_vector.getVector() );
  54
  55         // connecting lines should be put at start and end of path if it is not closed
  56         // it is not possible to check whether a piecewise<T> path is closed,
  57         // so we check whether start and end are close
  58         if ( ! are_near(pwd2_in.firstValue(), pwd2_in.lastValue()) ) {
  59             pwd2_out.concat( connector + pwd2_in.firstValue() );
  60             pwd2_out.concat( connector + pwd2_in.lastValue() );
  61         }
  62         // connecting lines should be put at cusps
  63         Piecewise<D2<SBasis> > deriv = derivative(pwd2_in);
  64         std::vector<double> cusps; // = roots(deriv);
  65         for (unsigned i = 0; i < cusps.size() ; ++i) {
  66             pwd2_out.concat( connector + pwd2_in.valueAt(cusps[i]) );
  67         }
  68         // connecting lines should be put where the tangent of the path equals the extrude_vector in direction
  69         std::vector<double> rts = roots(dot(deriv, rot90(extrude_vector.getVector())));
  70         for (unsigned i = 0; i < rts.size() ; ++i) {
  71             pwd2_out.concat( connector + pwd2_in.valueAt(rts[i]) );
  72         }
  73         return pwd2_out;
  74     }
  75
  76     case 1: {
  77         Piecewise<D2<SBasis> > pwd2_out;
  78         bool closed_path = are_near(pwd2_in.firstValue(), pwd2_in.lastValue());
  79         // split input path in pieces between points where deriv == vector
  80         Piecewise<D2<SBasis> > deriv = derivative(pwd2_in);
  81         std::vector<double> rts = roots(dot(deriv, rot90(extrude_vector.getVector())));
  82         double portion_t = 0.;
  83         for (unsigned i = 0; i < rts.size() ; ++i) {
  84             Piecewise<D2<SBasis> > cut = portion(pwd2_in, portion_t, rts[i] );
  85             portion_t = rts[i];
  86             if (closed_path && i == 0) {
  87                 // if the path is closed, skip the first cut and add it to the last cut later
  88                 continue;
  89             }
  90             Piecewise<D2<SBasis> > part = cut;
  91             part.continuousConcat(connector + cut.lastValue());
  92             part.continuousConcat(reverse(cut) + extrude_vector.getVector());
  93             part.continuousConcat(reverse(connector) + cut.firstValue());
  94             pwd2_out.concat( part );
  95         }
  96         if (closed_path) {
  97             Piecewise<D2<SBasis> > cut = portion(pwd2_in, portion_t, pwd2_in.domain().max() );
  98             cut.continuousConcat(portion(pwd2_in, pwd2_in.domain().min(), rts[0] ));
  99             Piecewise<D2<SBasis> > part = cut;
 100             part.continuousConcat(connector + cut.lastValue());
 101             part.continuousConcat(reverse(cut) + extrude_vector.getVector());
 102             part.continuousConcat(reverse(connector) + cut.firstValue());
 103             pwd2_out.concat( part );
 104         } else if (!are_near(portion_t, pwd2_in.domain().max())) {
 105             Piecewise<D2<SBasis> > cut = portion(pwd2_in, portion_t, pwd2_in.domain().max() );
 106             Piecewise<D2<SBasis> > part = cut;
 107             part.continuousConcat(connector + cut.lastValue());
 108             part.continuousConcat(reverse(cut) + extrude_vector.getVector());
 109             part.continuousConcat(reverse(connector) + cut.firstValue());
 110             pwd2_out.concat( part );
 111         }
 112         return pwd2_out;
 113     }
 114     }
 115 }
 116
 117 void
 118 LPEExtrude::resetDefaults(SPItem * item)
 119 {
 120     Effect::resetDefaults(item);
 121
 122     using namespace Geom;
 123
 124     Geom::OptRect bbox = item->getBounds(Geom::identity(), SPItem::GEOMETRIC_BBOX);
 125     if (bbox) {
 126         Interval boundingbox_X = (*bbox)[Geom::X];
 127         Interval boundingbox_Y = (*bbox)[Geom::Y];
 128         extrude_vector.set_and_write_new_values( Geom::Point(boundingbox_X.middle(), boundingbox_Y.middle()),
 129                                                  (boundingbox_X.extent() + boundingbox_Y.extent())*Geom::Point(-0.05,0.2) );
 130     }
 131 }
 132
 133 } //namespace LivePathEffect
 134 } /* namespace Inkscape */
 135
 136 /*
 137   Local Variables:
 138   mode:c++
 139   c-file-style:"stroustrup"
 140   c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
 141   indent-tabs-mode:nil
 142   fill-column:99
 143   End:
 144 */
 145 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4:encoding=utf-8:textwidth=99 :