402N/A

402N/A#include "live_effects/lpe-taperstroke.h"

402N/A

402N/A#include <2geom/path.h>

402N/A#include <2geom/shape.h>

402N/A#include <2geom/path.h>

402N/A#include <2geom/circle.h>

#include <2geom/sbasis-to-bezier.h>

#include "pathoutlineprovider.h"

#include "display/curve.h"

#include "sp-shape.h"

#include "style.h"

#include "xml/repr.h"

#include "sp-paint-server.h"

#include "svg/svg-color.h"

#include "desktop-style.h"

#include "svg/css-ostringstream.h"

#include "svg/svg.h"

#include "knot-holder-entity.h"

#include "knotholder.h"

namespace Inkscape {

namespace LivePathEffect {

namespace TpS {

class KnotHolderEntityAttachBegin : public LPEKnotHolderEntity {

public:

KnotHolderEntityAttachBegin(LPETaperStroke * effect) : LPEKnotHolderEntity(effect) {}

virtual void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state);

virtual Geom::Point knot_get() const;

};

class KnotHolderEntityAttachEnd : public LPEKnotHolderEntity {

public:

KnotHolderEntityAttachEnd(LPETaperStroke * effect) : LPEKnotHolderEntity(effect) {}

virtual void knot_set(Geom::Point const &p, Geom::Point const &origin, guint state);

virtual Geom::Point knot_get() const;

};

} // TpS

static const Util::EnumData<unsigned> JoinType[] = {

{LINEJOIN_STRAIGHT, N_("Beveled"), "bevel"},

{LINEJOIN_ROUND, N_("Rounded"), "round"},

{LINEJOIN_REFLECTED, N_("Reflected"), "reflected"},

{LINEJOIN_POINTY, N_("Miter"), "miter"},

{LINEJOIN_EXTRAPOLATED, N_("Extrapolated"), "extrapolated"}

};

static const Util::EnumDataConverter<unsigned> JoinTypeConverter(JoinType, sizeof (JoinType)/sizeof(*JoinType));

LPETaperStroke::LPETaperStroke(LivePathEffectObject *lpeobject) :

Effect(lpeobject),

line_width(_("Stroke width"), _("The (non-tapered) width of the path"), "stroke_width", &wr, this, 3),

attach_start(_("Start offset"), _("Taper distance from path start"), "attach_start", &wr, this, 0.2),

attach_end(_("End offset"), _("The ending position of the taper"), "end_offset", &wr, this, 0.2),

smoothing(_("Taper smoothing"), _("Amount of smoothing to apply to the tapers"), "smoothing", &wr, this, 0.5),

join_type(_("Join type"), _("Join type for non-smooth nodes"), "jointype", JoinTypeConverter, &wr, this, LINEJOIN_EXTRAPOLATED),

miter_limit(_("Miter limit"), _("Limit for miter joins"), "miter_limit", &wr, this, 30.)

{

show_orig_path = true;

_provides_knotholder_entities = true;

attach_start.param_set_digits(3);

attach_end.param_set_digits(3);

registerParameter( dynamic_cast<Parameter *>(&line_width) );

registerParameter( dynamic_cast<Parameter *>(&attach_start) );

registerParameter( dynamic_cast<Parameter *>(&attach_end) );

registerParameter( dynamic_cast<Parameter *>(&smoothing) );

registerParameter( dynamic_cast<Parameter *>(&join_type) );

registerParameter( dynamic_cast<Parameter *>(&miter_limit) );

}

LPETaperStroke::~LPETaperStroke()

{

}

void LPETaperStroke::doOnApply(SPLPEItem const* lpeitem)

{

if (SP_IS_SHAPE(lpeitem)) {

SPLPEItem* item = const_cast<SPLPEItem*>(lpeitem);

double width = (lpeitem && lpeitem->style) ? lpeitem->style->stroke_width.computed : 1.;

SPCSSAttr *css = sp_repr_css_attr_new ();

if (lpeitem->style->stroke.isSet()) {

if (lpeitem->style->stroke.isPaintserver()) {

SPPaintServer * server = lpeitem->style->getStrokePaintServer();

if (server) {

Glib::ustring str;

str += "url(#";

str += server->getId();

str += ")";

sp_repr_css_set_property (css, "fill", str.c_str());

}

} else if (lpeitem->style->stroke.isColor()) {

gchar c[64];

sp_svg_write_color (c, sizeof(c), lpeitem->style->stroke.value.color.toRGBA32(SP_SCALE24_TO_FLOAT(lpeitem->style->stroke_opacity.value)));

sp_repr_css_set_property (css, "fill", c);

} else {

sp_repr_css_set_property (css, "fill", "none");

}

} else {

sp_repr_css_unset_property (css, "fill");

}

sp_repr_css_set_property(css, "stroke", "none");

sp_desktop_apply_css_recursive(item, css, true);

sp_repr_css_attr_unref (css);

line_width.param_set_value(width);

} else {

g_warning("LPE Join Type can only be applied to paths (not groups).");

}

}

void LPETaperStroke::doOnRemove(SPLPEItem const* lpeitem)

{

if (SP_IS_SHAPE(lpeitem)) {

//TODO: make it getobjbyrepr instead of const_cast because this can cause

//undefined behavior

SPLPEItem *item = const_cast<SPLPEItem*>(lpeitem);

SPCSSAttr *css = sp_repr_css_attr_new ();

if (lpeitem->style->fill.isSet()) {

if (lpeitem->style->fill.isPaintserver()) {

SPPaintServer * server = lpeitem->style->getFillPaintServer();

if (server) {

Glib::ustring str;

str += "url(#";

str += server->getId();

str += ")";

sp_repr_css_set_property (css, "stroke", str.c_str());

}

} else if (lpeitem->style->fill.isColor()) {

gchar c[64];

sp_svg_write_color (c, sizeof(c), lpeitem->style->stroke.value.color.toRGBA32(SP_SCALE24_TO_FLOAT(lpeitem->style->stroke_opacity.value)));

sp_repr_css_set_property (css, "stroke", c);

} else {

sp_repr_css_set_property (css, "stroke", "none");

}

} else {

sp_repr_css_unset_property (css, "stroke");

}

Inkscape::CSSOStringStream os;

os << fabs(line_width);

sp_repr_css_set_property (css, "stroke-width", os.str().c_str());

sp_repr_css_set_property(css, "fill", "none");

sp_desktop_apply_css_recursive(item, css, true);

sp_repr_css_attr_unref (css);

item->updateRepr();

}

}

Geom::Path return_at_first_cusp (Geom::Path const & path_in, double smooth_tolerance = 0.05)

{

Geom::Path path_out = Geom::Path();

for (unsigned i = 0; i < path_in.size(); i++) {

path_out.append(path_in[i]);

if (path_in.size() == 1)

break;

//determine order of curve

int order = Outline::bezierOrder(&path_in[i]);

Geom::Point start_point;

Geom::Point cross_point = path_in[i].finalPoint();

Geom::Point end_point;

g_assert(path_in[i].finalPoint() == path_in[i+1].initialPoint());

//can you tell that the following expressions have been shaped by

//repeated compiler errors? ;)

switch (order) {

case 3:

start_point = (static_cast<const Geom::CubicBezier*>(&path_in[i]))->operator[] (2);

//major league b***f***ing

if (are_near(start_point, cross_point, 0.0000001)) {

start_point = (static_cast<const Geom::CubicBezier*>(&path_in[i]))->operator[] (1);

}

break;

case 2:

//this never happens

start_point = (static_cast<const Geom::QuadraticBezier*>(&path_in[i]))->operator[] (1);

break;

case 1:

default:

start_point = path_in[i].initialPoint();

}

order = Outline::bezierOrder(&path_in[i+1]);

switch (order) {

case 3:

end_point = (static_cast<const Geom::CubicBezier*>(&path_in[i+1]))->operator[] (1);

if (are_near(end_point, cross_point, 0.0000001)) {

end_point = (static_cast<const Geom::CubicBezier*>(&path_in[i+1]))->operator[] (2);

}

break;

case 2:

end_point = (static_cast<const Geom::QuadraticBezier*>(&path_in[i+1]))->operator[] (1);

break;

case 1:

default:

end_point = path_in[i+1].finalPoint();

}

//clearly it's collinear if two occupy the same point

g_assert(!are_near(start_point, cross_point, 0.0000001));

g_assert(!are_near(cross_point, end_point, 0.0000001));

g_assert(!are_near(start_point, end_point, 0.0000001));

if (!are_collinear(start_point, cross_point, end_point, smooth_tolerance))

break;

}

return path_out;

}

Geom::Piecewise<Geom::D2<Geom::SBasis> > stretch_along(Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2_in, Geom::Path pattern, double width);

void subdivideCurve(const Geom::Curve * curve_in, Geom::Coord t, Geom::Curve *& val_first, Geom::Curve *& val_second);

Geom::PathVector LPETaperStroke::doEffect_path(Geom::PathVector const& path_in)

{

Geom::Path first_cusp = return_at_first_cusp(path_in[0]);

Geom::Path last_cusp = return_at_first_cusp(path_in[0].reverse());

bool zeroStart = false;

bool zeroEnd = false;

//there is a pretty good chance that people will try to drag the knots

//on top of each other, so block it

unsigned size = path_in[0].size();

if (size == first_cusp.size()) {

//check to see if the knots were dragged over each other

//if so, reset the end offset

if ( attach_start >= (size - attach_end) ) {

attach_end.param_set_value( size - attach_start );

}

}

//don't let it be zero

if (attach_start <= 0.00000001) {

attach_start.param_set_value( 0.00000001 );

zeroStart = true;

}

if (attach_end <= 0.00000001) {

attach_end.param_set_value( 0.00000001 );

zeroEnd = true;

}

//don't let it be integer

if (double(unsigned(attach_start)) == attach_start) {

attach_start.param_set_value(attach_start - 0.00001);

}

if (double(unsigned(attach_end)) == attach_end) {

attach_end.param_set_value(attach_end - 0.00001);

}

unsigned allowed_start = first_cusp.size();

unsigned allowed_end = last_cusp.size();

//don't let the knots be farther than they are allowed to be

if ((unsigned)attach_start >= allowed_start) {

attach_start.param_set_value((double)allowed_start - 0.00000001);

}

if ((unsigned)attach_end >= allowed_end) {

attach_end.param_set_value((double)allowed_end - 0.00000001);

}

//remember, Path::operator () means get point at time t

start_attach_point = first_cusp(attach_start);

end_attach_point = last_cusp(attach_end);

Geom::PathVector pathv_out;

//the following function just splits it up into three pieces.

pathv_out = doEffect_simplePath(path_in);

//now for the actual tapering. We use a Pattern Along Path method to get this done.

Geom::PathVector real_pathv;

Geom::Path real_path;

Geom::PathVector pat_vec;

Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2;

Geom::Path throwaway_path;

if (!zeroStart) {

//Construct the pattern (pat_str stands for pattern string) (yes, this is easier, trust me)

std::stringstream pat_str;

pat_str << "M 1,0 C " << 1 - (double)smoothing << ",0 0,0.5 0,0.5 0,0.5 " << 1 - (double)smoothing << ",1 1,1";

pat_vec = sp_svg_read_pathv(pat_str.str().c_str());

pwd2.concat(stretch_along(pathv_out[0].toPwSb(), pat_vec[0], -fabs(line_width)));

throwaway_path = Geom::path_from_piecewise(pwd2, 0.001)[0];

real_path.append(throwaway_path);

}

//append the outside outline of the path (with direction)

throwaway_path = Outline::PathOutsideOutline(pathv_out[1],

-fabs(line_width), static_cast<LineJoinType>(join_type.get_value()), miter_limit);

real_path.append(throwaway_path, Geom::Path::STITCH_DISCONTINUOUS);

if (!zeroEnd) {

//append the ending taper

std::stringstream pat_str_1;

pat_str_1 << "M 0,0 0,1 C " << (double)smoothing << ",1 1,0.5 1,0.5 1,0.5 " << double(smoothing) << ",0 0,0";

pat_vec = sp_svg_read_pathv(pat_str_1.str().c_str());

pwd2 = Geom::Piecewise<Geom::D2<Geom::SBasis> > ();

pwd2.concat(stretch_along(pathv_out[2].toPwSb(), pat_vec[0], -fabs(line_width)));

throwaway_path = Geom::path_from_piecewise(pwd2, 0.001)[0];

real_path.append(throwaway_path, Geom::Path::STITCH_DISCONTINUOUS);

}

//append the inside outline of the path (against direction)

throwaway_path = Outline::PathOutsideOutline(pathv_out[1].reverse(),

-fabs(line_width), static_cast<LineJoinType>(join_type.get_value()), miter_limit);

real_path.append(throwaway_path, Geom::Path::STITCH_DISCONTINUOUS);

real_path.appendNew<Geom::LineSegment>(real_path.initialPoint());

real_path.close();

real_pathv.push_back(real_path);

return real_pathv;

}

Geom::PathVector LPETaperStroke::doEffect_simplePath(Geom::PathVector const & path_in)

{

unsigned size = path_in[0].size();

//do subdivision and get out

unsigned loc = (unsigned)attach_start;

Geom::Curve * curve_start = path_in[0] [loc].duplicate();

std::vector<Geom::Path> pathv_out;

Geom::Path path_out = Geom::Path();

Geom::Path trimmed_start = Geom::Path();

Geom::Path trimmed_end = Geom::Path();

for (unsigned i = 0; i < loc; i++) {

trimmed_start.append(path_in[0] [i]);

}

//this is pretty annoying

//previously I wrote a function for this but it wasted a lot of time

//so I optimized it back into here.

unsigned order = Outline::bezierOrder(curve_start);

switch (order) {

case 3: {

Geom::CubicBezier *cb = static_cast<Geom::CubicBezier * >(curve_start);

std::pair<Geom::CubicBezier, Geom::CubicBezier> cb_pair = cb->subdivide((attach_start - loc));

trimmed_start.append(cb_pair.first);

curve_start = cb_pair.second.duplicate(); //goes out of scope

break;

}

case 2: {

Geom::QuadraticBezier *qb = static_cast<Geom::QuadraticBezier * >(curve_start);

std::pair<Geom::QuadraticBezier, Geom::QuadraticBezier> qb_pair = qb->subdivide((attach_start - loc));

trimmed_start.append(qb_pair.first);

curve_start = qb_pair.second.duplicate();

break;

}

case 1: {

Geom::BezierCurveN<1> *lb = static_cast<Geom::BezierCurveN<1> * >(curve_start);

std::pair<Geom::BezierCurveN<1>, Geom::BezierCurveN<1> > lb_pair = lb->subdivide((attach_start - loc));

trimmed_start.append(lb_pair.first);

curve_start = lb_pair.second.duplicate();

break;

}

}

//special case: path is one segment long

//special case: what if the two knots occupy the same segment?

if ((size == 1) || ( size - unsigned(attach_end) - 1 == loc )) {

Geom::Coord t = Geom::nearest_point(end_attach_point, *curve_start);

//it is just a dumb segment

//we have to do some shifting here because the value changed when we reduced the length

//of the previous segment.

order = Outline::bezierOrder(curve_start);

switch (order) {

case 3: {

Geom::CubicBezier *cb = static_cast<Geom::CubicBezier * >(curve_start);

std::pair<Geom::CubicBezier, Geom::CubicBezier> cb_pair = cb->subdivide(t);

trimmed_end.append(cb_pair.second);

curve_start = cb_pair.first.duplicate();

break;

}

case 2: {

Geom::QuadraticBezier *qb = static_cast<Geom::QuadraticBezier * >(curve_start);

std::pair<Geom::QuadraticBezier, Geom::QuadraticBezier> qb_pair = qb->subdivide(t);

trimmed_end.append(qb_pair.second);

curve_start = qb_pair.first.duplicate();

break;

}

case 1: {

Geom::BezierCurveN<1> *lb = static_cast<Geom::BezierCurveN<1> * >(curve_start);

std::pair<Geom::BezierCurveN<1>, Geom::BezierCurveN<1> > lb_pair = lb->subdivide(t);

trimmed_end.append(lb_pair.second);

curve_start = lb_pair.first.duplicate();

break;

}

}

for (unsigned j = (size - attach_end) + 1; j < size; j++) {

trimmed_end.append(path_in[0] [j]);

}

path_out.append(*curve_start);

pathv_out.push_back(trimmed_start);

pathv_out.push_back(path_out);

pathv_out.push_back(trimmed_end);

return pathv_out;

}

pathv_out.push_back(trimmed_start);

//append almost all of the rest of the path, ignore the curves that the knot is past (we'll get to it in a minute)

path_out.append(*curve_start);

for (unsigned k = loc + 1; k < (size - unsigned(attach_end)) - 1; k++) {

path_out.append(path_in[0] [k]);

}

//deal with the last segment in a very similar fashion to the first

loc = size - attach_end;

Geom::Curve * curve_end = path_in[0] [loc].duplicate();

Geom::Coord t = Geom::nearest_point(end_attach_point, *curve_end);

order = Outline::bezierOrder(curve_end);

switch (order) {

case 3: {

Geom::CubicBezier *cb = static_cast<Geom::CubicBezier * >(curve_end);

std::pair<Geom::CubicBezier, Geom::CubicBezier> cb_pair = cb->subdivide(t);

trimmed_end.append(cb_pair.second);

curve_end = cb_pair.first.duplicate();

break;

}

case 2: {

Geom::QuadraticBezier *qb = static_cast<Geom::QuadraticBezier * >(curve_end);

std::pair<Geom::QuadraticBezier, Geom::QuadraticBezier> qb_pair = qb->subdivide(t);

trimmed_end.append(qb_pair.second);

curve_end = qb_pair.first.duplicate();

break;

}

case 1: {

Geom::BezierCurveN<1> *lb = static_cast<Geom::BezierCurveN<1> * >(curve_end);

std::pair<Geom::BezierCurveN<1>, Geom::BezierCurveN<1> > lb_pair = lb->subdivide(t);

trimmed_end.append(lb_pair.second);

curve_end = lb_pair.first.duplicate();

break;

}

}

for (unsigned j = (size - attach_end) + 1; j < size; j++) {

trimmed_end.append(path_in[0] [j]);

}

path_out.append(*curve_end);

pathv_out.push_back(path_out);

pathv_out.push_back(trimmed_end);

if (curve_end) delete curve_end;

if (curve_start) delete curve_start;

return pathv_out;

}

Geom::Piecewise<Geom::D2<Geom::SBasis> > stretch_along(Geom::Piecewise<Geom::D2<Geom::SBasis> > pwd2_in, Geom::Path pattern, double prop_scale)

{

using namespace Geom;

// Don't allow empty path parameter:

if ( pattern.empty() ) {

return pwd2_in;

}

/* Much credit should go to jfb and mgsloan of lib2geom development for the code below! */

Piecewise<D2<SBasis> > output;

std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > pre_output;

D2<Piecewise<SBasis> > patternd2 = make_cuts_independent(pattern.toPwSb());

Piecewise<SBasis> x0 = Piecewise<SBasis>(patternd2[0]);

Piecewise<SBasis> y0 = Piecewise<SBasis>(patternd2[1]);

OptInterval pattBndsX = bounds_exact(x0);

OptInterval pattBndsY = bounds_exact(y0);

if (pattBndsX && pattBndsY) {

x0 -= pattBndsX->min();

y0 -= pattBndsY->middle();

double xspace = 0;

double noffset = 0;

double toffset = 0;

/*if (prop_units.get_value() && pattBndsY){

//Prevent more than 90% overlap...

if (xspace < -pattBndsX->extent()*.9) {

xspace = -pattBndsX->extent()*.9;

}

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;

nbCopies = 1;

scaling = (uskeleton.domain().extent() - toffset)/pattBndsX->extent();

double pattWidth = pattBndsX->extent() * scaling;

if (scaling != 1.0) {

x*=scaling;

}

if ( false ) {

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++) {

if (false) {

Geom::Piecewise<Geom::D2<Geom::SBasis> > output_piece = compose(uskeleton,x+offs)+y*compose(n,x+offs);

std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > splited_output_piece = split_at_discontinuities(output_piece);

pre_output.insert(pre_output.end(), splited_output_piece.begin(), splited_output_piece.end() );

} else {

output.concat(compose(uskeleton,x+offs)+y*compose(n,x+offs));

}

offs+=pattWidth;

}

}

/*if (false){

return output;

} else {

return pwd2_in;

}

}

void subdivideCurve(Geom::Curve * curve_in, Geom::Coord t, Geom::Curve *& val_first, Geom::Curve *& val_second)

{

unsigned order = Outline::bezierOrder(curve_in);

switch (order) {

case 3: {

Geom::CubicBezier *cb = static_cast<Geom::CubicBezier * >(curve_in);

std::pair<Geom::CubicBezier, Geom::CubicBezier> cb_pair = cb->subdivide(t);

//trimmed_start.append(cb_pair.first);

val_first = cb_pair.first.duplicate();

val_second = cb_pair.second.duplicate();

break;

}

case 2: {

Geom::QuadraticBezier *qb = static_cast<Geom::QuadraticBezier * >(curve_in);

std::pair<Geom::QuadraticBezier, Geom::QuadraticBezier> qb_pair = qb->subdivide(t);

//trimmed_start.append(qb_pair.first);

val_first = qb_pair.first.duplicate();

val_second = qb_pair.second.duplicate();

break;

}

case 1: {

Geom::BezierCurveN<1> *lb = static_cast<Geom::BezierCurveN<1> * >(curve_in);

std::pair<Geom::BezierCurveN<1>, Geom::BezierCurveN<1> > lb_pair = lb->subdivide(t);

//trimmed_start.append(lb_pair.first);

val_first = lb_pair.first.duplicate();

val_second = lb_pair.second.duplicate();

break;

}

}

}

void LPETaperStroke::addKnotHolderEntities(KnotHolder *knotholder, SPDesktop *desktop, SPItem *item)

{

{

KnotHolderEntity *e = new TpS::KnotHolderEntityAttachBegin(this);

e->create( desktop, item, knotholder, Inkscape::CTRL_TYPE_UNKNOWN,

_("Start point of the taper"), SP_KNOT_SHAPE_CIRCLE );

knotholder->add(e);

}

{

KnotHolderEntity *e = new TpS::KnotHolderEntityAttachEnd(this);

e->create( desktop, item, knotholder, Inkscape::CTRL_TYPE_UNKNOWN,

_("End point of the taper"), SP_KNOT_SHAPE_CIRCLE );

knotholder->add(e);

}

}

namespace TpS {

void KnotHolderEntityAttachBegin::knot_set(Geom::Point const &p, Geom::Point const &/*origin*/, guint state)

{

using namespace Geom;

LPETaperStroke* lpe = dynamic_cast<LPETaperStroke *>(_effect);

Geom::Point const s = snap_knot_position(p, state);

SPCurve *curve = SP_PATH(item)->get_curve_for_edit();

Geom::PathVector pathv = curve->get_pathvector();

Piecewise<D2<SBasis> > pwd2;

Geom::Path p_in = return_at_first_cusp(pathv[0]);

pwd2.concat(p_in.toPwSb());

std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > pwd_vec = split_at_discontinuities(pwd2);

double t0 = nearest_point(s, pwd_vec[0]);

lpe->attach_start.param_set_value(t0);

// FIXME: this should not directly ask for updating the item. It should write to SVG, which triggers updating.

sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);

}

void KnotHolderEntityAttachEnd::knot_set(Geom::Point const &p, Geom::Point const& /*origin*/, guint state)

{

using namespace Geom;

LPETaperStroke* lpe = dynamic_cast<LPETaperStroke *>(_effect);

Geom::Point const s = snap_knot_position(p, state);

SPCurve *curve = SP_PATH(item)->get_curve_for_edit();

Geom::PathVector pathv = curve->get_pathvector();

Piecewise<D2<SBasis> > pwd2;

Geom::Path p_in = return_at_first_cusp(pathv[0].reverse());

pwd2.concat(p_in.toPwSb());

std::vector<Geom::Piecewise<Geom::D2<Geom::SBasis> > > pwd_vec = split_at_discontinuities(pwd2);

double t0 = nearest_point(s, pwd_vec[0]);

lpe->attach_end.param_set_value(t0);

// FIXME: this should not directly ask for updating the item. It should write to SVG, which triggers updating.

sp_lpe_item_update_patheffect (SP_LPE_ITEM(item), false, true);

}

Geom::Point KnotHolderEntityAttachBegin::knot_get() const

{

LPETaperStroke const * lpe = dynamic_cast<LPETaperStroke const*> (_effect);

return lpe->start_attach_point;

}

Geom::Point KnotHolderEntityAttachEnd::knot_get() const

{

LPETaperStroke const * lpe = dynamic_cast<LPETaperStroke const*> (_effect);

return lpe->end_attach_point;

}

}

} //namespace LivePathEffect

} /* namespace Inkscape */