1 #define INKSCAPE_LPE_INTERPOLATE_CPP
2 /** \file
3 * LPE interpolate implementation
4 */
5 /*
6 * Authors:
7 * Johan Engelen
8 *
9 * Copyright (C) Johan Engelen 2007-2008 <j.b.c.engelen@utwente.nl>
10 *
11 * Released under GNU GPL, read the file 'COPYING' for more information
12 */
14 #include "live_effects/lpe-interpolate.h"
16 #include <2geom/path.h>
17 #include <2geom/sbasis-to-bezier.h>
18 #include <2geom/d2-sbasis.h>
19 #include <2geom/piecewise.h>
20 #include <2geom/sbasis-geometric.h>
22 #include "sp-path.h"
23 #include "display/curve.h"
25 namespace Inkscape {
26 namespace LivePathEffect {
28 LPEInterpolate::LPEInterpolate(LivePathEffectObject *lpeobject) :
29 Effect(lpeobject),
30 trajectory_path(_("Trajectory"), _("Path along which intermediate steps are created."), "trajectory", &wr, this, "M0,0 L0,0"),
31 number_of_steps(_("Steps"), _("Determines the number of steps from start to end path."), "steps", &wr, this, 5),
32 equidistant_spacing(_("Equidistant spacing"), _("If true, the spacing between intermediates is constant along the length of the path. If false, the distance depends on the location of the nodes of the trajectory path."), "equidistant_spacing", &wr, this, true)
33 {
34 show_orig_path = true;
36 registerParameter( dynamic_cast<Parameter *>(&trajectory_path) );
37 registerParameter( dynamic_cast<Parameter *>(&equidistant_spacing) );
38 registerParameter( dynamic_cast<Parameter *>(&number_of_steps) );
40 number_of_steps.param_make_integer();
41 number_of_steps.param_set_range(2, NR_HUGE);
42 }
44 LPEInterpolate::~LPEInterpolate()
45 {
47 }
49 /*
50 * interpolate path_in[0] to path_in[1]
51 */
52 Geom::PathVector
53 LPEInterpolate::doEffect_path (Geom::PathVector const & path_in)
54 {
55 if ( (path_in.size() < 2) || (number_of_steps < 2)) {
56 return path_in;
57 }
58 // Don't allow empty path parameter:
59 if ( trajectory_path.get_pathvector().empty() ) {
60 return path_in;
61 }
63 std::vector<Geom::Path> path_out;
65 Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2_A = path_in[0].toPwSb();
66 Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2_B = path_in[1].toPwSb();
68 // Transform both paths to (0,0) midpoint, so they can easily be positioned along interpolate_path
69 if (Geom::OptRect bounds = Geom::bounds_exact(pwd2_A)) {
70 pwd2_A -= bounds->midpoint();
71 }
72 if (Geom::OptRect bounds = Geom::bounds_exact(pwd2_B)) {
73 pwd2_B -= bounds->midpoint();
74 }
76 // Make sure both paths have the same number of segments and cuts at the same locations
77 pwd2_B.setDomain(pwd2_A.domain());
78 Geom::Piecewise<Geom::D2<Geom::SBasis> > pA = Geom::partition(pwd2_A, pwd2_B.cuts);
79 Geom::Piecewise<Geom::D2<Geom::SBasis> > pB = Geom::partition(pwd2_B, pwd2_A.cuts);
81 Geom::Piecewise<Geom::D2<Geom::SBasis> > trajectory = trajectory_path.get_pathvector()[0].toPwSb();
82 if (equidistant_spacing)
83 trajectory = Geom::arc_length_parametrization(trajectory);
85 Geom::Interval trajectory_domain = trajectory.domain();
87 for (int i = 0; i < number_of_steps; ++i) {
88 double fraction = i / (number_of_steps-1);
90 Geom::Piecewise<Geom::D2<Geom::SBasis> > pResult = pA*(1-fraction) + pB*fraction;
91 pResult += trajectory.valueAt(trajectory_domain.min() + fraction*trajectory_domain.extent());
93 Geom::PathVector pathv = Geom::path_from_piecewise(pResult, LPE_CONVERSION_TOLERANCE);
94 path_out.push_back( pathv[0] );
95 }
97 return path_out;
98 }
100 void
101 LPEInterpolate::resetDefaults(SPItem * item)
102 {
103 Effect::resetDefaults(item);
105 if (!SP_IS_PATH(item))
106 return;
108 SPCurve const *crv = sp_path_get_curve_reference(SP_PATH(item));
109 Geom::PathVector const &pathv = crv->get_pathvector();
110 if ( (pathv.size() < 2) )
111 return;
113 Geom::OptRect bounds_A = pathv[0].boundsExact();
114 Geom::OptRect bounds_B = pathv[1].boundsExact();
116 if (bounds_A && bounds_B) {
117 Geom::PathVector traj_pathv;
118 traj_pathv.push_back( Geom::Path() );
119 traj_pathv[0].start( bounds_A->midpoint() );
120 traj_pathv[0].appendNew<Geom::LineSegment>( bounds_B->midpoint() );
121 trajectory_path.set_new_value( traj_pathv, true );
122 } else {
123 trajectory_path.param_set_and_write_default();
124 }
125 }
127 } //namespace LivePathEffect
128 } /* namespace Inkscape */
130 /*
131 Local Variables:
132 mode:c++
133 c-file-style:"stroustrup"
134 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
135 indent-tabs-mode:nil
136 fill-column:99
137 End:
138 */
139 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :