rename LPESkeletalStrokes -> LPEPatternAlongPath

(bzr r5386)

1 files changed, 244 insertions, 0 deletions

diff --git a/src/live_effects/lpe-patternalongpath.cpp b/src/live_effects/lpe-patternalongpath.cpp
new file mode 100644
index 000000000..9b2819219
--- /dev/null
+++ b/src/live_effects/lpe-patternalongpath.cpp
@@ -0,0 +1,244 @@
+#define INKSCAPE_LPE_PATTERN_ALONG_PATH_CPP
+
+/*
+ * Copyright (C) Johan Engelen 2007 <j.b.c.engelen@utwente.nl>
+ *
+ * Released under GNU GPL, read the file 'COPYING' for more information
+ */
+
+#include "live_effects/lpe-patternalongpath.h"
+#include "sp-shape.h"
+#include "display/curve.h"
+#include <libnr/n-art-bpath.h>
+#include "live_effects/n-art-bpath-2geom.h"
+#include "svg/svg.h"
+#include "ui/widget/scalar.h"
+
+#include <2geom/sbasis.h>
+#include <2geom/sbasis-geometric.h>
+#include <2geom/bezier-to-sbasis.h>
+#include <2geom/sbasis-to-bezier.h>
+#include <2geom/d2.h>
+#include <2geom/piecewise.h>
+
+#include <algorithm>
+using std::vector;
+
+
+/* Theory in e-mail from J.F. Barraud
+Let B be the skeleton path, and P the pattern (the path to be deformed).
+
+P is a map t --> P(t) = ( x(t), y(t) ).
+B is a map t --> B(t) = ( a(t), b(t) ).
+
+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
+U(s) is s itself.
+
+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).
+
+The basic deformation associated to B is then given by:
+
+   (x,y) --> U(x)+y*N(x)
+
+(i.e. we go for distance x along the path, and then for distance y along the normal)
+
+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
+first) but I think we can first forget about them.
+*/
+
+namespace Inkscape {
+namespace LivePathEffect {
+
+static const Util::EnumData<PAPCopyType> PAPCopyTypeData[PAPCT_END] = {
+    {PAPCT_SINGLE,               N_("Single"),               "single"},
+    {PAPCT_SINGLE_STRETCHED,     N_("Single, stretched"),    "single_stretched"},
+    {PAPCT_REPEATED,             N_("Repeated"),             "repeated"},
+    {PAPCT_REPEATED_STRETCHED,   N_("Repeated, stretched"),  "repeated_stretched"}
+};
+static const Util::EnumDataConverter<PAPCopyType> PAPCopyTypeConverter(PAPCopyTypeData, PAPCT_END);
+
+LPEPatternAlongPath::LPEPatternAlongPath(LivePathEffectObject *lpeobject) :
+    Effect(lpeobject),
+    pattern(_("Pattern source"), _("Path to put along the skeleton path"), "pattern", &wr, this, "M0,0 L1,0"),
+    copytype(_("Pattern copies"), _("How many pattern copies to place along the skeleton path"), "copytype", PAPCopyTypeConverter, &wr, this, PAPCT_SINGLE_STRETCHED),
+    prop_scale(_("Width"), _("Width of the pattern"), "prop_scale", &wr, this, 1),
+    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),
+    spacing(_("Spacing"), _("Space between copies of the pattern. Negative values allowed, but are limited to -90% of pattern width."), "spacing", &wr, this, 0),
+    normal_offset(_("Normal offset"), "", "normal_offset", &wr, this, 0),
+    tang_offset(_("Tangential offset"), "", "tang_offset", &wr, this, 0),
+    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),
+    vertical_pattern(_("Pattern is vertical"), "Rotate pattern 90 deg before applying", "vertical_pattern", &wr, this, false)
+{
+    registerParameter( dynamic_cast<Parameter *>(&pattern) );
+    registerParameter( dynamic_cast<Parameter *>(&copytype) );
+    registerParameter( dynamic_cast<Parameter *>(&prop_scale) );
+    registerParameter( dynamic_cast<Parameter *>(&scale_y_rel) );
+    registerParameter( dynamic_cast<Parameter *>(&spacing) );
+    registerParameter( dynamic_cast<Parameter *>(&normal_offset) );
+    registerParameter( dynamic_cast<Parameter *>(&tang_offset) );
+    registerParameter( dynamic_cast<Parameter *>(&prop_units) );
+    registerParameter( dynamic_cast<Parameter *>(&vertical_pattern) );
+
+    prop_scale.param_set_digits(3);
+    prop_scale.param_set_increments(0.01, 0.10);
+}
+
+LPEPatternAlongPath::~LPEPatternAlongPath()
+{
+
+}
+
+
+//TODO: does this already exist in 2Geom? if not, move this there...
+static
+std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > 
+split_at_discontinuities (Geom::Piecewise<Geom::D2<Geom::SBasis> > & pwsbin, double tol = .0001)
+{
+    using namespace Geom;
+    std::vector<Piecewise<D2<SBasis> > > ret;
+    unsigned piece_start = 0;
+    for (unsigned i=0; i<pwsbin.segs.size(); i++){
+        if (i==(pwsbin.segs.size()-1) || L2(pwsbin.segs[i].at1()- pwsbin.segs[i+1].at0()) > tol){
+            Piecewise<D2<SBasis> > piece;
+            piece.cuts.push_back(pwsbin.cuts[piece_start]);
+            for (unsigned j = piece_start; j<i+1; j++){
+                piece.segs.push_back(pwsbin.segs[j]);
+                piece.cuts.push_back(pwsbin.cuts[j+1]);                
+            }
+            ret.push_back(piece);
+            piece_start = i+1;
+        }
+    }
+    return ret;
+}
+
+
+Geom::Piecewise<Geom::D2<Geom::SBasis> >
+LPEPatternAlongPath::doEffect_pwd2 (Geom::Piecewise<Geom::D2<Geom::SBasis> > & pwd2_in)
+{
+    using namespace Geom;
+
+/* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */
+    Piecewise<D2<SBasis> > output;
+
+    PAPCopyType type = copytype.get_value();
+
+    D2<Piecewise<SBasis> > patternd2 = make_cuts_independant(pattern.get_pwd2());
+    Piecewise<SBasis> x0 = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[1]) : Piecewise<SBasis>(patternd2[0]);
+    Piecewise<SBasis> y0 = vertical_pattern.get_value() ? Piecewise<SBasis>(patternd2[0]) : Piecewise<SBasis>(patternd2[1]);
+    Interval pattBndsX = bounds_exact(x0);
+    x0 -= pattBndsX.min();
+    Interval pattBndsY = bounds_exact(y0);
+    y0 -= pattBndsY.middle();
+
+    double xspace  = spacing;
+    double noffset = normal_offset;
+    double toffset = tang_offset;
+    if (prop_units.get_value()){
+        xspace  *= pattBndsX.extent();
+        noffset *= pattBndsY.extent();
+        toffset *= pattBndsX.extent();
+    }
+
+    //Prevent more than 90% overlap...
+    if (xspace < -pattBndsX.extent()*.9) {
+        xspace = -pattBndsX.extent()*.9;
+    }
+    //TODO: dynamical update of parameter ranges?
+    //if (prop_units.get_value()){
+    //        spacing.param_set_range(-.9, NR_HUGE);
+    //    }else{
+    //        spacing.param_set_range(-pattBndsX.extent()*.9, NR_HUGE);
+    //    }
+
+    y0+=noffset;
+
+    std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > paths_in;
+    paths_in = split_at_discontinuities(pwd2_in);
+
+    for (unsigned idx = 0; idx < paths_in.size(); idx++){
+        Geom::Piecewise<Geom::D2<Geom::SBasis> > path_i = paths_in[idx];
+        Piecewise<SBasis> x = x0;
+        Piecewise<SBasis> y = y0;
+        Piecewise<D2<SBasis> > uskeleton = arc_length_parametrization(path_i,2,.1);
+        uskeleton = remove_short_cuts(uskeleton,.01);
+        Piecewise<D2<SBasis> > n = rot90(derivative(uskeleton));
+        n = force_continuity(remove_short_cuts(n,.1));
+        
+        int nbCopies = 0;
+        double scaling = 1;
+        switch(type) {
+            case PAPCT_REPEATED:
+                nbCopies = floor((uskeleton.domain().extent() - toffset + xspace)/(pattBndsX.extent()+xspace));
+                pattBndsX = Interval(pattBndsX.min(),pattBndsX.max()+xspace);
+                break;
+                
+            case PAPCT_SINGLE:
+                nbCopies = (toffset + pattBndsX.extent() < uskeleton.domain().extent()) ? 1 : 0;
+                break;
+                
+            case PAPCT_SINGLE_STRETCHED:
+                nbCopies = 1;
+                scaling = (uskeleton.domain().extent() - toffset)/pattBndsX.extent();
+                break;
+                
+            case PAPCT_REPEATED_STRETCHED:
+                // if uskeleton is closed:
+                if(path_i.segs.front().at0() == path_i.segs.back().at1()){
+                    nbCopies = std::floor((uskeleton.domain().extent() - toffset)/(pattBndsX.extent()+xspace));
+                    pattBndsX = Interval(pattBndsX.min(),pattBndsX.max()+xspace);
+                    scaling = (uskeleton.domain().extent() - toffset)/(((double)nbCopies)*pattBndsX.extent());
+                    // if not closed: no space at the end
+                }else{
+                    nbCopies = std::floor((uskeleton.domain().extent() - toffset + xspace)/(pattBndsX.extent()+xspace));
+                    pattBndsX = Interval(pattBndsX.min(),pattBndsX.max()+xspace);
+                    scaling = (uskeleton.domain().extent() - toffset)/(((double)nbCopies)*pattBndsX.extent() - xspace);
+                }
+                break;
+                
+            default:
+                return pwd2_in;
+        };
+        
+        double pattWidth = pattBndsX.extent() * scaling;
+        
+        if (scaling != 1.0) {
+            x*=scaling;
+        }
+        if ( scale_y_rel.get_value() ) {
+            y*=(scaling*prop_scale);
+        } else {
+            if (prop_scale != 1.0) y *= prop_scale;
+        }
+        x += toffset;
+        
+        double offs = 0;
+        for (int i=0; i<nbCopies; i++){
+            output.concat(compose(uskeleton,x+offs)+y*compose(n,x+offs));
+            offs+=pattWidth;
+        }
+    }
+    return output;
+}
+
+void
+LPEPatternAlongPath::transform_multiply(Geom::Matrix const& postmul, bool set)
+{
+    // TODO: implement correct transformation instead of this default behavior
+    Effect::transform_multiply(postmul, set);
+}
+
+
+} // namespace LivePathEffect
+} /* namespace Inkscape */
+
+/*
+  Local Variables:
+  mode:c++
+  c-file-style:"stroustrup"
+  c-file-offsets:((innamespace . 0)(inline-open . 0)(case-label . +))
+  indent-tabs-mode:nil
+  fill-column:99
+  End:
+*/
+// vim: filetype=cpp:expandtab:shiftwidth=4:tabstop=8:softtabstop=4 :