void
PolylineCollection::chained_path_from(Point start_near, PolylineCollection* retval, bool no_reverse) const
{
Polylines my_paths = this->polylines;
Points endpoints; //里面存储所有polyline里面的第一个点和允许翻转时的最后一个点的坐标
for (Polylines::const_iterator it = my_paths.begin(); it != my_paths.end(); ++it) {
endpoints.push_back(it->first_point());
if (no_reverse) {
endpoints.push_back(it->first_point());
} else {
endpoints.push_back(it->last_point());
}
}
while (!my_paths.empty()) {
// find nearest point
int start_index = start_near.nearest_point_index(endpoints);
int path_index = start_index/2;
if (start_index % 2 && !no_reverse) {
my_paths.at(path_index).reverse();
}
retval->polylines.push_back(my_paths.at(path_index));
my_paths.erase(my_paths.begin() + path_index);
endpoints.erase(endpoints.begin() + 2*path_index, endpoints.begin() + 2*path_index + 2);
start_near = retval->polylines.back().last_point();
}
}
ExtrusionEntityCollection
PerimeterGenerator::_fill_gaps(double min, double max, double w,
const Polygons &gaps) const
{
ExtrusionEntityCollection coll;
min *= (1 - INSET_OVERLAP_TOLERANCE);
ExPolygons curr = diff_ex(
offset2(gaps, -min/2, +min/2),
offset2(gaps, -max/2, +max/2),
true
);
Polylines polylines;
for (ExPolygons::const_iterator ex = curr.begin(); ex != curr.end(); ++ex)
ex->medial_axis(max, min/2, &polylines);
if (polylines.empty())
return coll;
#ifdef SLIC3R_DEBUG
if (!curr.empty())
printf(" %zu gaps filled with extrusion width = %f\n", curr.size(), w);
#endif
//my $flow = $layerm->flow(FLOW_ROLE_SOLID_INFILL, 0, $w);
Flow flow(
w, this->layer_height, this->solid_infill_flow.nozzle_diameter
);
double mm3_per_mm = flow.mm3_per_mm();
for (Polylines::const_iterator p = polylines.begin(); p != polylines.end(); ++p) {
ExtrusionPath path(erGapFill);
path.polyline = *p;
path.mm3_per_mm = mm3_per_mm;
path.width = flow.width;
path.height = this->layer_height;
if (p->is_valid() && p->first_point().coincides_with(p->last_point())) {
// since medial_axis() now returns only Polyline objects, detect loops here
ExtrusionLoop loop;
loop.paths.push_back(path);
coll.append(loop);
} else {
coll.append(path);
}
}
return coll;
}
bool
BridgeDetector::detect_angle()
{
if (this->_edges.empty() || this->_anchors.empty()) return false;
/* Outset the bridge expolygon by half the amount we used for detecting anchors;
we'll use this one to clip our test lines and be sure that their endpoints
are inside the anchors and not on their contours leading to false negatives. */
Polygons clip_area;
offset(this->expolygon, &clip_area, +this->extrusion_width/2);
/* we'll now try several directions using a rudimentary visibility check:
bridge in several directions and then sum the length of lines having both
endpoints within anchors */
// we test angles according to configured resolution
std::vector<double> angles;
for (int i = 0; i <= PI/this->resolution; ++i)
angles.push_back(i * this->resolution);
// we also test angles of each bridge contour
{
Polygons pp = this->expolygon;
for (Polygons::const_iterator p = pp.begin(); p != pp.end(); ++p) {
Lines lines = p->lines();
for (Lines::const_iterator line = lines.begin(); line != lines.end(); ++line)
angles.push_back(line->direction());
}
}
/* we also test angles of each open supporting edge
(this finds the optimal angle for C-shaped supports) */
for (Polylines::const_iterator edge = this->_edges.begin(); edge != this->_edges.end(); ++edge) {
if (edge->first_point().coincides_with(edge->last_point())) continue;
angles.push_back(Line(edge->first_point(), edge->last_point()).direction());
}
// remove duplicates
double min_resolution = PI/180.0; // 1 degree
std::sort(angles.begin(), angles.end());
for (size_t i = 1; i < angles.size(); ++i) {
if (xd::Geometry::directions_parallel(angles[i], angles[i-1], min_resolution)) {
angles.erase(angles.begin() + i);
--i;
}
}
/* compare first value with last one and remove the greatest one (PI)
in case they are parallel (PI, 0) */
if (xd::Geometry::directions_parallel(angles.front(), angles.back(), min_resolution))
angles.pop_back();
BridgeDirectionComparator bdcomp(this->extrusion_width);
double line_increment = this->extrusion_width;
bool have_coverage = false;
for (std::vector<double>::const_iterator angle = angles.begin(); angle != angles.end(); ++angle) {
Polygons my_clip_area = clip_area;
ExPolygons my_anchors = this->_anchors;
// rotate everything - the center point doesn't matter
for (Polygons::iterator it = my_clip_area.begin(); it != my_clip_area.end(); ++it)
it->rotate(-*angle, Point(0,0));
for (ExPolygons::iterator it = my_anchors.begin(); it != my_anchors.end(); ++it)
it->rotate(-*angle, Point(0,0));
// generate lines in this direction
BoundingBox bb;
for (ExPolygons::const_iterator it = my_anchors.begin(); it != my_anchors.end(); ++it)
bb.merge((Points)*it);
Lines lines;
for (coord_t y = bb.min.y; y <= bb.max.y; y += line_increment)
lines.push_back(Line(Point(bb.min.x, y), Point(bb.max.x, y)));
Lines clipped_lines;
intersection(lines, my_clip_area, &clipped_lines);
// remove any line not having both endpoints within anchors
for (size_t i = 0; i < clipped_lines.size(); ++i) {
Line &line = clipped_lines[i];
if (!xd::Geometry::contains(my_anchors, line.a)
|| !xd::Geometry::contains(my_anchors, line.b)) {
clipped_lines.erase(clipped_lines.begin() + i);
--i;
}
}
std::vector<double> lengths;
double total_length = 0;
for (Lines::const_iterator line = clipped_lines.begin(); line != clipped_lines.end(); ++line) {
double len = line->length();
lengths.push_back(len);
total_length += len;
}
if (total_length) have_coverage = true;
// sum length of bridged lines
bdcomp.dir_coverage[*angle] = total_length;
/* The following produces more correct results in some cases and more broken in others.
TODO: investigate, as it looks more reliable than line clipping. */
// $directions_coverage{$angle} = sum(map $_->area, @{$self->coverage($angle)}) // 0;
// max length of bridged lines
bdcomp.dir_avg_length[*angle] = !lengths.empty()
? *std::max_element(lengths.begin(), lengths.end())
: 0;
}
// if no direction produced coverage, then there's no bridge direction
if (!have_coverage) return false;
// sort directions by score
std::sort(angles.begin(), angles.end(), bdcomp);
this->angle = angles.front();
if (this->angle >= PI) this->angle -= PI;
// #ifdef SLIC3R_DEBUG
// printf(" Optimal infill angle is %d degrees\n", (int)Slic3r::Geometry::rad2deg(this->angle));
// #endif
return true;
}