PrusaSlicer-NonPlainar/xs/src/libslic3r/Polyline.cpp

264 lines
7.5 KiB
C++

#include "Polyline.hpp"
#include "ExPolygon.hpp"
#include "ExPolygonCollection.hpp"
#include "Line.hpp"
#include "Polygon.hpp"
#include <iostream>
namespace Slic3r {
Polyline::operator Polylines() const
{
Polylines polylines;
polylines.push_back(*this);
return polylines;
}
Polyline::operator Line() const
{
if (this->points.size() > 2) CONFESS("Can't convert polyline with more than two points to a line");
return Line(this->points.front(), this->points.back());
}
Point
Polyline::last_point() const
{
return this->points.back();
}
Point
Polyline::leftmost_point() const
{
Point p = this->points.front();
for (Points::const_iterator it = this->points.begin() + 1; it != this->points.end(); ++it) {
if (it->x < p.x) p = *it;
}
return p;
}
Lines
Polyline::lines() const
{
Lines lines;
if (this->points.size() >= 2) {
lines.reserve(this->points.size() - 1);
for (Points::const_iterator it = this->points.begin(); it != this->points.end()-1; ++it) {
lines.push_back(Line(*it, *(it + 1)));
}
}
return lines;
}
// removes the given distance from the end of the polyline
void
Polyline::clip_end(double distance)
{
while (distance > 0) {
Point last_point = this->last_point();
this->points.pop_back();
if (this->points.empty()) break;
double last_segment_length = last_point.distance_to(this->last_point());
if (last_segment_length <= distance) {
distance -= last_segment_length;
continue;
}
Line segment(last_point, this->last_point());
this->points.push_back(segment.point_at(distance));
distance = 0;
}
}
// removes the given distance from the start of the polyline
void
Polyline::clip_start(double distance)
{
this->reverse();
this->clip_end(distance);
if (this->points.size() >= 2) this->reverse();
}
void
Polyline::extend_end(double distance)
{
// relocate last point by extending the last segment by the specified length
Line line(this->points[ this->points.size()-2 ], this->points.back());
this->points.pop_back();
this->points.push_back(line.point_at(line.length() + distance));
}
void
Polyline::extend_start(double distance)
{
// relocate first point by extending the first segment by the specified length
Line line(this->points[1], this->points.front());
this->points[0] = line.point_at(line.length() + distance);
}
/* this method returns a collection of points picked on the polygon contour
so that they are evenly spaced according to the input distance */
Points
Polyline::equally_spaced_points(double distance) const
{
Points points;
points.push_back(this->first_point());
double len = 0;
for (Points::const_iterator it = this->points.begin() + 1; it != this->points.end(); ++it) {
double segment_length = it->distance_to(*(it-1));
len += segment_length;
if (len < distance) continue;
if (len == distance) {
points.push_back(*it);
len = 0;
continue;
}
double take = segment_length - (len - distance); // how much we take of this segment
Line segment(*(it-1), *it);
points.push_back(segment.point_at(take));
--it;
len = -take;
}
return points;
}
void
Polyline::simplify(double tolerance)
{
this->points = MultiPoint::_douglas_peucker(this->points, tolerance);
}
/* This method simplifies all *lines* contained in the supplied area */
template <class T>
void
Polyline::simplify_by_visibility(const T &area)
{
Points &pp = this->points;
// find first point in area
size_t s = 0;
while (s < pp.size() && !area.contains(pp[s])) {
++s;
}
// find last point in area
size_t e = pp.size()-1;
while (e > 0 && !area.contains(pp[e])) {
--e;
}
// this ugly algorithm resembles a binary search
while (e > s + 1) {
size_t mid = (s + e) / 2;
if (area.contains(Line(pp[s], pp[mid]))) {
pp.erase(pp.begin() + s + 1, pp.begin() + mid);
// repeat recursively until no further simplification is possible
++s;
e = pp.size()-1;
} else {
e = mid;
}
}
/*
// The following implementation is complete but it's not efficient at all:
for (size_t s = start; s < pp.size() && !pp.empty(); ++s) {
// find the farthest point to which we can build
// a line that is contained in the supplied area
// a binary search would be more efficient for this
for (size_t e = pp.size()-1; e > (s + 1); --e) {
if (area.contains(Line(pp[s], pp[e]))) {
// we can suppress points between s and e
pp.erase(pp.begin() + s + 1, pp.begin() + e);
// repeat recursively until no further simplification is possible
return this->simplify_by_visibility(area);
}
}
}
*/
}
template void Polyline::simplify_by_visibility<ExPolygon>(const ExPolygon &area);
template void Polyline::simplify_by_visibility<ExPolygonCollection>(const ExPolygonCollection &area);
void
Polyline::split_at(const Point &point, Polyline* p1, Polyline* p2) const
{
if (this->points.empty()) return;
// find the line to split at
size_t line_idx = 0;
Point p = this->first_point();
double min = point.distance_to(p);
Lines lines = this->lines();
for (Lines::const_iterator line = lines.begin(); line != lines.end(); ++line) {
Point p_tmp = point.projection_onto(*line);
if (point.distance_to(p_tmp) < min) {
p = p_tmp;
min = point.distance_to(p);
line_idx = line - lines.begin();
}
}
// create first half
p1->points.clear();
for (Lines::const_iterator line = lines.begin(); line != lines.begin() + line_idx + 1; ++line) {
if (!line->a.coincides_with(p)) p1->points.push_back(line->a);
}
// we add point instead of p because they might differ because of numerical issues
// and caller might want to rely on point belonging to result polylines
p1->points.push_back(point);
// create second half
p2->points.clear();
p2->points.push_back(point);
for (Lines::const_iterator line = lines.begin() + line_idx; line != lines.end(); ++line) {
p2->points.push_back(line->b);
}
}
bool
Polyline::is_straight() const
{
/* Check that each segment's direction is equal to the line connecting
first point and last point. (Checking each line against the previous
one would cause the error to accumulate.) */
double dir = Line(this->first_point(), this->last_point()).direction();
Lines lines = this->lines();
for (Lines::const_iterator line = lines.begin(); line != lines.end(); ++line) {
if (!line->parallel_to(dir)) return false;
}
return true;
}
std::string
Polyline::wkt() const
{
std::ostringstream wkt;
wkt << "LINESTRING((";
for (Points::const_iterator p = this->points.begin(); p != this->points.end(); ++p) {
wkt << p->x << " " << p->y;
if (p != this->points.end()-1) wkt << ",";
}
wkt << "))";
return wkt.str();
}
#ifdef SLIC3RXS
REGISTER_CLASS(Polyline, "Polyline");
void
Polyline::from_SV_check(SV* poly_sv)
{
if (!sv_isa(poly_sv, perl_class_name(this)) && !sv_isa(poly_sv, perl_class_name_ref(this)))
CONFESS("Not a valid %s object",perl_class_name(this));
MultiPoint::from_SV_check(poly_sv);
}
#endif
}