/** Make a path from a d2 sbasis.
\param p the d2 Symmetric basis polynomial
\returns a Path
If only_cubicbeziers is true, the resulting path may only contain CubicBezier curves.
*/
void build_from_sbasis(Geom::PathBuilder &pb, D2<SBasis> const &B, double tol, bool only_cubicbeziers) {
if (!B.isFinite()) {
THROW_EXCEPTION("assertion failed: B.isFinite()");
}
if(tail_error(B, 2) < tol || sbasis_size(B) == 2) { // nearly cubic enough
if( !only_cubicbeziers && (sbasis_size(B) <= 1) ) {
pb.lineTo(B.at1());
} else {
std::vector<Geom::Point> bez;
sbasis_to_bezier(bez, B, 4);
pb.curveTo(bez[1], bez[2], bez[3]);
}
} else {
build_from_sbasis(pb, compose(B, Linear(0, 0.5)), tol, only_cubicbeziers);
build_from_sbasis(pb, compose(B, Linear(0.5, 1)), tol, only_cubicbeziers);
}
}
// Create path for rendering shape on screen
void SPGenericEllipse::set_shape()
{
// std::cout << "SPGenericEllipse::set_shape: Entrance" << std::endl;
if (hasBrokenPathEffect()) {
g_warning("The ellipse shape has unknown LPE on it! Convert to path to make it editable preserving the appearance; editing it as ellipse will remove the bad LPE");
if (this->getRepr()->attribute("d")) {
// unconditionally read the curve from d, if any, to preserve appearance
Geom::PathVector pv = sp_svg_read_pathv(this->getRepr()->attribute("d"));
SPCurve *cold = new SPCurve(pv);
this->setCurveInsync(cold, TRUE);
cold->unref();
}
return;
}
if (Geom::are_near(this->rx.computed, 0) || Geom::are_near(this->ry.computed, 0)) {
return;
}
this->normalize();
SPCurve *curve = NULL;
// For simplicity, we use a circle with center (0, 0) and radius 1 for our calculations.
Geom::Circle circle(0, 0, 1);
if (!this->_isSlice()) {
start = 0.0;
end = 2.0*M_PI;
}
double incr = end - start; // arc angle
if (incr < 0.0) incr += 2.0*M_PI;
int numsegs = 1 + int(incr*2.0/M_PI); // number of arc segments
if (numsegs > 4) numsegs = 4;
incr = incr/numsegs; // limit arc angle to less than 90 degrees
Geom::Path path(Geom::Point::polar(start));
Geom::EllipticalArc* arc;
for (int seg = 0; seg < numsegs; seg++) {
arc = circle.arc(Geom::Point::polar(start + seg*incr), Geom::Point::polar(start + (seg + 0.5)*incr), Geom::Point::polar(start + (seg + 1.0)*incr));
path.append(*arc);
delete arc;
}
Geom::PathBuilder pb;
pb.append(path);
if (this->_isSlice() && this->_closed) {
pb.lineTo(Geom::Point(0, 0));
}
if (this->_closed) {
pb.closePath();
} else {
pb.flush();
}
curve = new SPCurve(pb.peek());
// gchar *str = sp_svg_write_path(curve->get_pathvector());
// std::cout << " path: " << str << std::endl;
// g_free(str);
// Stretching / moving the calculated shape to fit the actual dimensions.
Geom::Affine aff = Geom::Scale(rx.computed, ry.computed) * Geom::Translate(cx.computed, cy.computed);
curve->transform(aff);
/* Reset the shape's curve to the "original_curve"
* This is very important for LPEs to work properly! (the bbox might be recalculated depending on the curve in shape)*/
this->setCurveInsync(curve, TRUE);
this->setCurveBeforeLPE(curve);
if (hasPathEffect() && pathEffectsEnabled()) {
SPCurve *c_lpe = curve->copy();
bool success = this->performPathEffect(c_lpe);
if (success) {
this->setCurveInsync(c_lpe, TRUE);
}
c_lpe->unref();
}
curve->unref();
// std::cout << "SPGenericEllipse::set_shape: Exit" << std::endl;
}