1 #define INKSCAPE_LPE_PATTERN_ALONG_PATH_CPP
3 /*
4 * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
5 *
6 * Released under GNU GPL, read the file 'COPYING' for more information
7 */
9 #include "live_effects/lpe-patternalongpath.h"
10 #include "sp-shape.h"
11 #include "display/curve.h"
12 #include <libnr/n-art-bpath.h>
13 #include "libnr/n-art-bpath-2geom.h"
14 #include "svg/svg.h"
15 #include "ui/widget/scalar.h"
17 #include <2geom/sbasis.h>
18 #include <2geom/sbasis-geometric.h>
19 #include <2geom/bezier-to-sbasis.h>
20 #include <2geom/sbasis-to-bezier.h>
21 #include <2geom/d2.h>
22 #include <2geom/piecewise.h>
24 #include <algorithm>
25 using std::vector;
28 /* Theory in e-mail from J.F. Barraud
29 Let B be the skeleton path, and P the pattern (the path to be deformed).
31 P is a map t --> P(t) = ( x(t), y(t) ).
32 B is a map t --> B(t) = ( a(t), b(t) ).
34 The first step is to re-parametrize B by its arc length: this is the parametrization in which a point p on B is located by its distance s from start. One obtains a new map s --> U(s) = (a'(s),b'(s)), that still describes the same path B, but where the distance along B from start to
35 U(s) is s itself.
37 We also need a unit normal to the path. This can be obtained by computing a unit tangent vector, and rotate it by 90°. Call this normal vector N(s).
39 The basic deformation associated to B is then given by:
41 (x,y) --> U(x)+y*N(x)
43 (i.e. we go for distance x along the path, and then for distance y along the normal)
45 Of course this formula needs some minor adaptations (as is it depends on the absolute position of P for instance, so a little translation is needed
46 first) but I think we can first forget about them.
47 */
49 namespace Inkscape {
50 namespace LivePathEffect {
52 static const Util::EnumData<PAPCopyType> PAPCopyTypeData[PAPCT_END] = {
53 {PAPCT_SINGLE, N_("Single"), "single"},
54 {PAPCT_SINGLE_STRETCHED, N_("Single, stretched"), "single_stretched"},
55 {PAPCT_REPEATED, N_("Repeated"), "repeated"},
56 {PAPCT_REPEATED_STRETCHED, N_("Repeated, stretched"), "repeated_stretched"}
57 };
58 static const Util::EnumDataConverter<PAPCopyType> PAPCopyTypeConverter(PAPCopyTypeData, PAPCT_END);
60 LPEPatternAlongPath::LPEPatternAlongPath(LivePathEffectObject *lpeobject) :
61 Effect(lpeobject),
62 pattern(_("Pattern source"), _("Path to put along the skeleton path"), "pattern", &wr, this, "M0,0 L1,0"),
63 copytype(_("Pattern copies"), _("How many pattern copies to place along the skeleton path"), "copytype", PAPCopyTypeConverter, &wr, this, PAPCT_SINGLE_STRETCHED),
64 prop_scale(_("Width"), _("Width of the pattern"), "prop_scale", &wr, this, 1),
65 scale_y_rel(_("Width in units of length"), _("Scale the width of the pattern in units of its length"), "scale_y_rel", &wr, this, false),
66 spacing(_("Spacing"), _("Space between copies of the pattern. Negative values allowed, but are limited to -90% of pattern width."), "spacing", &wr, this, 0),
67 normal_offset(_("Normal offset"), "", "normal_offset", &wr, this, 0),
68 tang_offset(_("Tangential offset"), "", "tang_offset", &wr, this, 0),
69 prop_units(_("Offsets in unit of pattern size"), _("Spacing, tangential and normal offset are expressed as a ratio of width/height"), "prop_units", &wr, this, false),
70 vertical_pattern(_("Pattern is vertical"), _("Rotate pattern 90 deg before applying"), "vertical_pattern", &wr, this, false)
71 {
72 registerParameter( dynamic_cast<Parameter *>(&pattern) );
73 registerParameter( dynamic_cast<Parameter *>(©type) );
74 registerParameter( dynamic_cast<Parameter *>(&prop_scale) );
75 registerParameter( dynamic_cast<Parameter *>(&scale_y_rel) );
76 registerParameter( dynamic_cast<Parameter *>(&spacing) );
77 registerParameter( dynamic_cast<Parameter *>(&normal_offset) );
78 registerParameter( dynamic_cast<Parameter *>(&tang_offset) );
79 registerParameter( dynamic_cast<Parameter *>(&prop_units) );
80 registerParameter( dynamic_cast<Parameter *>(&vertical_pattern) );
82 prop_scale.param_set_digits(3);
83 prop_scale.param_set_increments(0.01, 0.10);
84 }
86 LPEPatternAlongPath::~LPEPatternAlongPath()
87 {
89 }
91 Geom::Piecewise<Geom::D2<Geom::SBasis> >
92 LPEPatternAlongPath::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
93 {
94 using namespace Geom;
96 /* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
97 Piecewise<D2<SBasis> > output;
99 PAPCopyType type = copytype.get_value();
101 D2<Piecewise<SBasis> > patternd2 = make_cuts_independent(pattern.get_pwd2());
102 Piecewise<SBasis> x0 = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[1]) : Piecewise<SBasis>(patternd2[0]);
103 Piecewise<SBasis> y0 = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[0]) : Piecewise<SBasis>(patternd2[1]);
104 Interval pattBndsX = bounds_exact(x0);
105 x0 -= pattBndsX.min();
106 Interval pattBndsY = bounds_exact(y0);
107 y0 -= pattBndsY.middle();
109 double xspace = spacing;
110 double noffset = normal_offset;
111 double toffset = tang_offset;
112 if (prop_units.get_value()){
113 xspace *= pattBndsX.extent();
114 noffset *= pattBndsY.extent();
115 toffset *= pattBndsX.extent();
116 }
118 //Prevent more than 90% overlap...
119 if (xspace < -pattBndsX.extent()*.9) {
120 xspace = -pattBndsX.extent()*.9;
121 }
122 //TODO: dynamical update of parameter ranges?
123 //if (prop_units.get_value()){
124 // spacing.param_set_range(-.9, NR_HUGE);
125 // }else{
126 // spacing.param_set_range(-pattBndsX.extent()*.9, NR_HUGE);
127 // }
129 y0+=noffset;
131 std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > paths_in;
132 paths_in = split_at_discontinuities(pwd2_in);
134 for (unsigned idx = 0; idx < paths_in.size(); idx++){
135 Geom::Piecewise<Geom::D2<Geom::SBasis> > path_i = paths_in[idx];
136 Piecewise<SBasis> x = x0;
137 Piecewise<SBasis> y = y0;
138 Piecewise<D2<SBasis> > uskeleton = arc_length_parametrization(path_i,2,.1);
139 uskeleton = remove_short_cuts(uskeleton,.01);
140 Piecewise<D2<SBasis> > n = rot90(derivative(uskeleton));
141 n = force_continuity(remove_short_cuts(n,.1));
143 int nbCopies = 0;
144 double scaling = 1;
145 switch(type) {
146 case PAPCT_REPEATED:
147 nbCopies = static_cast<int>(floor((uskeleton.domain().extent() - toffset + xspace)/(pattBndsX.extent()+xspace)));
148 pattBndsX = Interval(pattBndsX.min(),pattBndsX.max()+xspace);
149 break;
151 case PAPCT_SINGLE:
152 nbCopies = (toffset + pattBndsX.extent() < uskeleton.domain().extent()) ? 1 : 0;
153 break;
155 case PAPCT_SINGLE_STRETCHED:
156 nbCopies = 1;
157 scaling = (uskeleton.domain().extent() - toffset)/pattBndsX.extent();
158 break;
160 case PAPCT_REPEATED_STRETCHED:
161 // if uskeleton is closed:
162 if(path_i.segs.front().at0() == path_i.segs.back().at1()){
163 nbCopies = static_cast<int>(std::floor((uskeleton.domain().extent() - toffset)/(pattBndsX.extent()+xspace)));
164 pattBndsX = Interval(pattBndsX.min(),pattBndsX.max()+xspace);
165 scaling = (uskeleton.domain().extent() - toffset)/(((double)nbCopies)*pattBndsX.extent());
166 // if not closed: no space at the end
167 }else{
168 nbCopies = static_cast<int>(std::floor((uskeleton.domain().extent() - toffset + xspace)/(pattBndsX.extent()+xspace)));
169 pattBndsX = Interval(pattBndsX.min(),pattBndsX.max()+xspace);
170 scaling = (uskeleton.domain().extent() - toffset)/(((double)nbCopies)*pattBndsX.extent() - xspace);
171 }
172 break;
174 default:
175 return pwd2_in;
176 };
178 double pattWidth = pattBndsX.extent() * scaling;
180 if (scaling != 1.0) {
181 x*=scaling;
182 }
183 if ( scale_y_rel.get_value() ) {
184 y*=(scaling*prop_scale);
185 } else {
186 if (prop_scale != 1.0) y *= prop_scale;
187 }
188 x += toffset;
190 double offs = 0;
191 for (int i=0; i<nbCopies; i++){
192 output.concat(compose(uskeleton,x+offs)+y*compose(n,x+offs));
193 offs+=pattWidth;
194 }
195 }
196 return output;
197 }
199 void
200 LPEPatternAlongPath::transform_multiply(Geom::Matrix const& postmul, bool set)
201 {
202 // TODO: implement correct transformation instead of this default behavior
203 Effect::transform_multiply(postmul, set);
204 }
207 } // namespace LivePathEffect
208 } /* namespace Inkscape */
210 /*
211 Local Variables:
212 mode:c++
213 c-file-style:"stroustrup"
214 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
215 indent-tabs-mode:nil
216 fill-column:99
217 End:
218 */
219 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :