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 "live_effects/lpeobject.h"
11 #include "sp-shape.h"
12 #include "display/curve.h"
13 #include "svg/svg.h"
14 #include "ui/widget/scalar.h"
16 #include <2geom/sbasis.h>
17 #include <2geom/sbasis-geometric.h>
18 #include <2geom/bezier-to-sbasis.h>
19 #include <2geom/sbasis-to-bezier.h>
20 #include <2geom/d2.h>
21 #include <2geom/piecewise.h>
23 #include <algorithm>
24 using std::vector;
27 /* Theory in e-mail from J.F. Barraud
28 Let B be the skeleton path, and P the pattern (the path to be deformed).
30 P is a map t --> P(t) = ( x(t), y(t) ).
31 B is a map t --> B(t) = ( a(t), b(t) ).
33 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
34 U(s) is s itself.
36 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).
38 The basic deformation associated to B is then given by:
40 (x,y) --> U(x)+y*N(x)
42 (i.e. we go for distance x along the path, and then for distance y along the normal)
44 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
45 first) but I think we can first forget about them.
46 */
48 namespace Inkscape {
49 namespace LivePathEffect {
51 static const Util::EnumData<PAPCopyType> PAPCopyTypeData[PAPCT_END] = {
52 {PAPCT_SINGLE, N_("Single"), "single"},
53 {PAPCT_SINGLE_STRETCHED, N_("Single, stretched"), "single_stretched"},
54 {PAPCT_REPEATED, N_("Repeated"), "repeated"},
55 {PAPCT_REPEATED_STRETCHED, N_("Repeated, stretched"), "repeated_stretched"}
56 };
57 static const Util::EnumDataConverter<PAPCopyType> PAPCopyTypeConverter(PAPCopyTypeData, PAPCT_END);
59 LPEPatternAlongPath::LPEPatternAlongPath(LivePathEffectObject *lpeobject) :
60 Effect(lpeobject),
61 pattern(_("Pattern source"), _("Path to put along the skeleton path"), "pattern", &wr, this, "M0,0 L1,0"),
62 copytype(_("Pattern copies"), _("How many pattern copies to place along the skeleton path"),
63 "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"),
66 _("Scale the width of the pattern in units of its length"),
67 "scale_y_rel", &wr, this, false),
68 spacing(_("Spacing"),
69 // xgettext:no-c-format
70 _("Space between copies of the pattern. Negative values allowed, but are limited to -90% of pattern width."),
71 "spacing", &wr, this, 0),
72 normal_offset(_("Normal offset"), "", "normal_offset", &wr, this, 0),
73 tang_offset(_("Tangential offset"), "", "tang_offset", &wr, this, 0),
74 prop_units(_("Offsets in unit of pattern size"),
75 _("Spacing, tangential and normal offset are expressed as a ratio of width/height"),
76 "prop_units", &wr, this, false),
77 vertical_pattern(_("Pattern is vertical"), _("Rotate pattern 90 deg before applying"),
78 "vertical_pattern", &wr, this, false),
79 fuse_tolerance(_("Fuse nearby ends"), _("Fuse ends closer than this number. 0 means don't fuse."),
80 "fuse_tolerance", &wr, this, 0)
81 {
82 registerParameter( dynamic_cast<Parameter *>(&pattern) );
83 registerParameter( dynamic_cast<Parameter *>(©type) );
84 registerParameter( dynamic_cast<Parameter *>(&prop_scale) );
85 registerParameter( dynamic_cast<Parameter *>(&scale_y_rel) );
86 registerParameter( dynamic_cast<Parameter *>(&spacing) );
87 registerParameter( dynamic_cast<Parameter *>(&normal_offset) );
88 registerParameter( dynamic_cast<Parameter *>(&tang_offset) );
89 registerParameter( dynamic_cast<Parameter *>(&prop_units) );
90 registerParameter( dynamic_cast<Parameter *>(&vertical_pattern) );
91 registerParameter( dynamic_cast<Parameter *>(&fuse_tolerance) );
93 prop_scale.param_set_digits(3);
94 prop_scale.param_set_increments(0.01, 0.10);
95 }
97 LPEPatternAlongPath::~LPEPatternAlongPath()
98 {
100 }
102 Geom::Piecewise<Geom::D2<Geom::SBasis> >
103 LPEPatternAlongPath::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > const & pwd2_in)
104 {
105 using namespace Geom;
107 /* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
108 Piecewise<D2<SBasis> > output;
109 std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > pre_output;
111 PAPCopyType type = copytype.get_value();
113 D2<Piecewise<SBasis> > patternd2 = make_cuts_independent(pattern.get_pwd2());
114 Piecewise<SBasis> x0 = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[1]) : Piecewise<SBasis>(patternd2[0]);
115 Piecewise<SBasis> y0 = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[0]) : Piecewise<SBasis>(patternd2[1]);
116 OptInterval pattBndsX = bounds_exact(x0);
117 OptInterval pattBndsY = bounds_exact(y0);
118 if (pattBndsX && pattBndsY) {
119 x0 -= pattBndsX->min();
120 y0 -= pattBndsY->middle();
122 double xspace = spacing;
123 double noffset = normal_offset;
124 double toffset = tang_offset;
125 if (prop_units.get_value() && pattBndsY){
126 xspace *= pattBndsX->extent();
127 noffset *= pattBndsY->extent();
128 toffset *= pattBndsX->extent();
129 }
131 //Prevent more than 90% overlap...
132 if (xspace < -pattBndsX->extent()*.9) {
133 xspace = -pattBndsX->extent()*.9;
134 }
135 //TODO: dynamical update of parameter ranges?
136 //if (prop_units.get_value()){
137 // spacing.param_set_range(-.9, NR_HUGE);
138 // }else{
139 // spacing.param_set_range(-pattBndsX.extent()*.9, NR_HUGE);
140 // }
142 y0+=noffset;
144 std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > paths_in;
145 paths_in = split_at_discontinuities(pwd2_in);
147 for (unsigned idx = 0; idx < paths_in.size(); idx++){
148 Geom::Piecewise<Geom::D2<Geom::SBasis> > path_i = paths_in[idx];
149 Piecewise<SBasis> x = x0;
150 Piecewise<SBasis> y = y0;
151 Piecewise<D2<SBasis> > uskeleton = arc_length_parametrization(path_i,2,.1);
152 uskeleton = remove_short_cuts(uskeleton,.01);
153 Piecewise<D2<SBasis> > n = rot90(derivative(uskeleton));
154 n = force_continuity(remove_short_cuts(n,.1));
156 int nbCopies = 0;
157 double scaling = 1;
158 switch(type) {
159 case PAPCT_REPEATED:
160 nbCopies = static_cast<int>(floor((uskeleton.domain().extent() - toffset + xspace)/(pattBndsX->extent()+xspace)));
161 pattBndsX = Interval(pattBndsX->min(),pattBndsX->max()+xspace);
162 break;
164 case PAPCT_SINGLE:
165 nbCopies = (toffset + pattBndsX->extent() < uskeleton.domain().extent()) ? 1 : 0;
166 break;
168 case PAPCT_SINGLE_STRETCHED:
169 nbCopies = 1;
170 scaling = (uskeleton.domain().extent() - toffset)/pattBndsX->extent();
171 break;
173 case PAPCT_REPEATED_STRETCHED:
174 // if uskeleton is closed:
175 if(path_i.segs.front().at0() == path_i.segs.back().at1()){
176 nbCopies = static_cast<int>(std::floor((uskeleton.domain().extent() - toffset)/(pattBndsX->extent()+xspace)));
177 pattBndsX = Interval(pattBndsX->min(),pattBndsX->max()+xspace);
178 scaling = (uskeleton.domain().extent() - toffset)/(((double)nbCopies)*pattBndsX->extent());
179 // if not closed: no space at the end
180 }else{
181 nbCopies = static_cast<int>(std::floor((uskeleton.domain().extent() - toffset + xspace)/(pattBndsX->extent()+xspace)));
182 pattBndsX = Interval(pattBndsX->min(),pattBndsX->max()+xspace);
183 scaling = (uskeleton.domain().extent() - toffset)/(((double)nbCopies)*pattBndsX->extent() - xspace);
184 }
185 break;
187 default:
188 return pwd2_in;
189 };
191 double pattWidth = pattBndsX->extent() * scaling;
193 if (scaling != 1.0) {
194 x*=scaling;
195 }
196 if ( scale_y_rel.get_value() ) {
197 y*=(scaling*prop_scale);
198 } else {
199 if (prop_scale != 1.0) y *= prop_scale;
200 }
201 x += toffset;
203 double offs = 0;
204 for (int i=0; i<nbCopies; i++){
205 if (fuse_tolerance > 0){
206 Geom::Piecewise<Geom::D2<Geom::SBasis> > output_piece = compose(uskeleton,x+offs)+y*compose(n,x+offs);
207 std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > splited_output_piece = split_at_discontinuities(output_piece);
208 pre_output.insert(pre_output.end(), splited_output_piece.begin(), splited_output_piece.end() );
209 }else{
210 output.concat(compose(uskeleton,x+offs)+y*compose(n,x+offs));
211 }
212 offs+=pattWidth;
213 }
214 }
215 if (fuse_tolerance > 0){
216 pre_output = fuse_nearby_ends(pre_output, fuse_tolerance);
217 for (unsigned i=0; i<pre_output.size(); i++){
218 output.concat(pre_output[i]);
219 }
220 }
221 return output;
222 } else {
223 return pwd2_in;
224 }
225 }
227 } // namespace LivePathEffect
228 } /* namespace Inkscape */
230 /*
231 Local Variables:
232 mode:c++
233 c-file-style:"stroustrup"
234 c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
235 indent-tabs-mode:nil
236 fill-column:99
237 End:
238 */
239 // vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :