lpe-taperstroke.cpp revision 76addc201c409e81eaaa73fe27cc0f79c4db097c
/**
* @file
* Taper Stroke path effect, provided as an alternative to Power Strokes
* for otherwise constant-width paths.
*
* Authors:
* Liam P White <inkscapebrony@gmail.com>
*
* Copyright (C) 2014 Authors
*
* Released under GNU GPL, read the file 'COPYING' for more information
*/
#include "live_effects/lpe-taperstroke.h"
#include <2geom/path.h>
#include <2geom/path.h>
#include <2geom/circle.h>
#include <2geom/sbasis-to-bezier.h>
#include "helper/geom-nodetype.h"
#include "helper/geom-pathstroke.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"
#include <glibmm/i18n.h>
template<typename T>
inline bool withinRange(T value, T low, T high) {
return (value > low && value < high);
}
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[] = {
{JOIN_BEVEL, N_("Beveled"), "bevel"},
{JOIN_ROUND, N_("Rounded"), "round"},
{JOIN_MITER, N_("Miter"), "miter"},
{JOIN_EXTRAPOLATE, 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, 1.),
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, JOIN_EXTRAPOLATE),
miter_limit(_("Miter limit:"), _("Limit for miter joins"), "miter_limit", &wr, this, 100.)
{
show_orig_path = true;
_provides_knotholder_entities = true;
attach_start.param_set_digits(3);
attach_end.param_set_digits(3);
registerParameter(&line_width);
registerParameter(&attach_start);
registerParameter(&attach_end);
registerParameter(&smoothing);
registerParameter(&join_type);
registerParameter(&miter_limit);
}
// from LPEPowerStroke -- sets fill if stroke color because we will
// be converting to a fill to make the new join.
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.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");
}
sp_repr_css_set_property(css, "fill-rule", "nonzero");
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 {
printf("WARNING: It only makes sense to apply Taper stroke to paths (not groups).\n");
}
}
// from LPEPowerStroke -- sets stroke color from existing fill color
void LPETaperStroke::doOnRemove(SPLPEItem const* lpeitem)
{
if (SP_IS_SHAPE(lpeitem)) {
SPLPEItem *item = const_cast<SPLPEItem*>(lpeitem);
SPCSSAttr *css = sp_repr_css_attr_new ();
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->fill.value.color.toRGBA32(SP_SCALE24_TO_FLOAT(lpeitem->style->fill_opacity.value)));
sp_repr_css_set_property (css, "stroke", c);
} else {
sp_repr_css_set_property (css, "stroke", "none");
}
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);
}
}
using Geom::Piecewise;
using Geom::D2;
using Geom::SBasis;
// leave Geom::Path
static Geom::Path return_at_first_cusp(Geom::Path const & path_in, double /*smooth_tolerance*/ = 0.05)
{
Geom::Path temp;
for (unsigned i = 0; i < path_in.size(); i++) {
temp.append(path_in[i]);
if (Geom::get_nodetype(path_in[i], path_in[i + 1]) != Geom::NODE_SMOOTH ) {
break;
}
}
return temp;
}
Piecewise<D2<SBasis> > stretch_along(Piecewise<D2<SBasis> > pwd2_in, Geom::Path pattern, double width);
// actual effect
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].reversed());
bool zeroStart = false; // [distance from start taper knot -> start of path] == 0
bool zeroEnd = false; // [distance from end taper knot -> end of path] == 0
bool metInMiddle = false; // knots are touching
// 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, but still allow the start offset.
if ( attach_start >= (size - attach_end) ) {
attach_end.param_set_value( size - attach_start );
metInMiddle = true;
}
}
if (attach_start == size - attach_end) {
metInMiddle = true;
}
if (attach_end == size - attach_start) {
metInMiddle = true;
}
// don't let it be integer (TODO this is stupid!)
{
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 - 0.00001);
}
if ((unsigned)attach_end >= allowed_end) {
attach_end.param_set_value((double)allowed_end - 0.00001);
}
}
// don't let it be zero (this is stupid too!)
if (attach_start < 0.0000001 || withinRange(double(attach_start), 0.00000001, 0.000001)) {
attach_start.param_set_value( 0.0000001 );
zeroStart = true;
}
if (attach_end < 0.0000001 || withinRange(double(attach_end), 0.00000001, 0.000001)) {
attach_end.param_set_value( 0.0000001 );
zeroEnd = true;
}
// 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. the stretch_along method (stolen from PaP) is used to accomplish this
Geom::PathVector real_pathv;
Geom::Path real_path;
Geom::PathVector pat_vec;
Piecewise<D2<SBasis> > pwd2;
Geom::Path throwaway_path;
if (!zeroStart) {
// Construct the pattern
std::stringstream pat_str;
pat_str.imbue(std::locale::classic());
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, LPE_CONVERSION_TOLERANCE)[0];
real_path.append(throwaway_path);
}
// if this condition happens to evaluate false, i.e. there was no space for a path to be drawn, it is simply skipped.
// although this seems obvious, it can probably lead to bugs.
if (!metInMiddle) {
// append the outside outline of the path (goes with the direction of the path)
throwaway_path = half_outline(pathv_out[1], fabs(line_width)/2., miter_limit, static_cast<LineJoinType>(join_type.get_value()));
if (!zeroStart && real_path.size() >= 1 && throwaway_path.size() >= 1) {
if (!Geom::are_near(real_path.finalPoint(), throwaway_path.initialPoint())) {
real_path.appendNew<Geom::LineSegment>(throwaway_path.initialPoint());
} else {
real_path.setFinal(throwaway_path.initialPoint());
}
}
real_path.append(throwaway_path);
}
if (!zeroEnd) {
// append the ending taper
std::stringstream pat_str_1;
pat_str_1.imbue(std::locale::classic());
pat_str_1 << "M 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 = Piecewise<D2<SBasis> >();
pwd2.concat(stretch_along(pathv_out[2].toPwSb(), pat_vec[0], -fabs(line_width)));
throwaway_path = Geom::path_from_piecewise(pwd2, LPE_CONVERSION_TOLERANCE)[0];
if (!Geom::are_near(real_path.finalPoint(), throwaway_path.initialPoint()) && real_path.size() >= 1) {
real_path.appendNew<Geom::LineSegment>(throwaway_path.initialPoint());
} else {
real_path.setFinal(throwaway_path.initialPoint());
}
real_path.append(throwaway_path);
}
if (!metInMiddle) {
// append the inside outline of the path (against direction)
throwaway_path = half_outline(pathv_out[1].reversed(), fabs(line_width)/2., miter_limit, static_cast<LineJoinType>(join_type.get_value()));
if (!Geom::are_near(real_path.finalPoint(), throwaway_path.initialPoint()) && real_path.size() >= 1) {
real_path.appendNew<Geom::LineSegment>(throwaway_path.initialPoint());
} else {
real_path.setFinal(throwaway_path.initialPoint());
}
real_path.append(throwaway_path);
}
if (!Geom::are_near(real_path.finalPoint(), real_path.initialPoint())) {
real_path.appendNew<Geom::LineSegment>(real_path.initialPoint());
} else {
real_path.setFinal(real_path.initialPoint());
}
real_path.close();
real_pathv.push_back(real_path);
return real_pathv;
}
/**
* @return Always returns a PathVector with three elements.
*
* The positions of the effect knots are accessed to determine
* where exactly the input path should be split.
*/
Geom::PathVector LPETaperStroke::doEffect_simplePath(Geom::PathVector const & path_in)
{
Geom::Coord endTime = path_in[0].size() - attach_end;
Geom::Path p1 = path_in[0].portion(0., attach_start);
Geom::Path p2 = path_in[0].portion(attach_start, endTime);
Geom::Path p3 = path_in[0].portion(endTime, path_in[0].size());
Geom::PathVector out;
out.push_back(p1);
out.push_back(p2);
out.push_back(p3);
return out;
}
/**
* Most of the below function is verbatim from Pattern Along Path. However, it needed a little
* tweaking to get it to work right in this case. Also, large portions of the effect have been
* stripped out as I deemed them unnecessary for the relative simplicity of this effect.
*/
Piecewise<D2<SBasis> > stretch_along(Piecewise<D2<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<Piecewise<D2<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;
// Prevent more than 90% overlap...
if (xspace < -pattBndsX->extent()*.9) {
xspace = -pattBndsX->extent()*.9;
}
y0+=noffset;
std::vector<Piecewise<D2<SBasis> > > paths_in;
paths_in = split_at_discontinuities(pwd2_in);
for (unsigned idx = 0; idx < paths_in.size(); idx++) {
Piecewise<D2<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) {
Piecewise<D2<SBasis> > output_piece = compose(uskeleton,x+offs)+y*compose(n,x+offs);
std::vector<Piecewise<D2<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;
}
}
return output;
} else {
return pwd2_in;
}
}
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 *f = new TpS::KnotHolderEntityAttachEnd(this);
f->create(desktop, item, knotholder, Inkscape::CTRL_TYPE_UNKNOWN, _("End point of the taper"), SP_KNOT_SHAPE_CIRCLE);
knotholder->add(f);
}
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);
if (!SP_IS_SHAPE(lpe->sp_lpe_item)) {
printf("WARNING: LPEItem is not a path!\n");
return;
}
SPCurve* curve;
if (!(curve = SP_SHAPE(lpe->sp_lpe_item)->getCurve())) {
// oops
return;
}
// in case you are wondering, the above are simply sanity checks. we never want to actually
// use that object.
Geom::PathVector pathv = lpe->pathvector_before_effect;
Piecewise<D2<SBasis> > pwd2;
Geom::Path p_in = return_at_first_cusp(pathv[0]);
pwd2.concat(p_in.toPwSb());
double t0 = nearest_time(s, pwd2);
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);
if (!SP_IS_SHAPE(lpe->sp_lpe_item) ) {
printf("WARNING: LPEItem is not a path!\n");
return;
}
SPCurve* curve;
if ( !(curve = SP_SHAPE(lpe->sp_lpe_item)->getCurve()) ) {
// oops
return;
}
Geom::PathVector pathv = lpe->pathvector_before_effect;
Geom::Path p_in = return_at_first_cusp(pathv[0].reversed());
Piecewise<D2<SBasis> > pwd2 = p_in.toPwSb();
double t0 = nearest_time(s, pwd2);
lpe->attach_end.param_set_value(t0);
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 TpS
} // 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:fileencoding=utf-8 :