Classes
struct	Parameters

Functions
void	process_classic (const Parameters &params, const Surface &surface, const ExPolygons *lower_slices, Polygons &lower_slices_polygons_cache, ExtrusionEntityCollection &out_loops, ExtrusionEntityCollection &out_gap_fill, ExPolygons &out_fill_expolygons)

void	process_arachne (const Parameters &params, const Surface &surface, const ExPolygons *lower_slices, Polygons &lower_slices_polygons_cache, ExtrusionEntityCollection &out_loops, ExtrusionEntityCollection &out_gap_fill, ExPolygons &out_fill_expolygons)

ExtrusionMultiPath	thick_polyline_to_multi_path (const ThickPolyline &thick_polyline, ExtrusionRole role, const Flow &flow, float tolerance, float merge_tolerance)

Function Documentation

◆ process_arachne()

void Slic3r::PerimeterGenerator::process_arachne	(	const Parameters &	params,
		const Surface &	surface,
		const ExPolygons *	lower_slices,
		Polygons &	lower_slices_polygons_cache,
		ExtrusionEntityCollection &	out_loops,
		ExtrusionEntityCollection &	out_gap_fill,
		ExPolygons &	out_fill_expolygons
	)

{
    // other perimeters
    coord_t perimeter_spacing     = params.perimeter_flow.scaled_spacing();
    // external perimeters
    coord_t ext_perimeter_width    = params.ext_perimeter_flow.scaled_width();
    coord_t ext_perimeter_spacing  = params.ext_perimeter_flow.scaled_spacing();
    coord_t ext_perimeter_spacing2 = scaled<coord_t>(0.5f * (params.ext_perimeter_flow.spacing() + params.perimeter_flow.spacing()));
    // solid infill
    coord_t solid_infill_spacing  = params.solid_infill_flow.scaled_spacing();
 
    // prepare grown lower layer slices for overhang detection
    if (params.config.overhangs && lower_slices != nullptr && lower_slices_polygons_cache.empty()) {
        // We consider overhang any part where the entire nozzle diameter is not supported by the
        // lower layer, so we take lower slices and offset them by half the nozzle diameter used
        // in the current layer
        double nozzle_diameter = params.print_config.nozzle_diameter.get_at(params.config.perimeter_extruder-1);
        lower_slices_polygons_cache = offset(*lower_slices, float(scale_(+nozzle_diameter/2)));
    }
 
    // we need to process each island separately because we might have different
    // extra perimeters for each one
    // detect how many perimeters must be generated for this island
    int        loop_number = params.config.perimeters + surface.extra_perimeters - 1; // 0-indexed loops
    ExPolygons last        = offset_ex(surface.expolygon.simplify_p(params.scaled_resolution), - float(ext_perimeter_width / 2. - ext_perimeter_spacing / 2.));
    Polygons   last_p      = to_polygons(last);
 
    Arachne::WallToolPaths wallToolPaths(last_p, ext_perimeter_spacing, perimeter_spacing, coord_t(loop_number + 1), 0, params.layer_height, params.object_config, params.print_config);
    std::vector<Arachne::VariableWidthLines> perimeters = wallToolPaths.getToolPaths();
    loop_number = int(perimeters.size()) - 1;
 
#ifdef ARACHNE_DEBUG
    {
        static int iRun = 0;
        export_perimeters_to_svg(debug_out_path("arachne-perimeters-%d-%d.svg", layer_id, iRun++), to_polygons(last), perimeters, union_ex(wallToolPaths.getInnerContour()));
    }
#endif
 
    // All closed ExtrusionLine should have the same the first and the last point.
    // But in rare cases, Arachne produce ExtrusionLine marked as closed but without
    // equal the first and the last point.
    assert([&perimeters = std::as_const(perimeters)]() -> bool {
        for (const Arachne::VariableWidthLines &perimeter : perimeters)
            for (const Arachne::ExtrusionLine &el : perimeter)
                if (el.is_closed && el.junctions.front().p != el.junctions.back().p)
                    return false;
        return true;
    }());
 
    int start_perimeter = int(perimeters.size()) - 1;
    int end_perimeter   = -1;
    int direction       = -1;
 
    if (params.config.external_perimeters_first) {
        start_perimeter = 0;
        end_perimeter   = int(perimeters.size());
        direction       = 1;
    }
 
    std::vector<Arachne::ExtrusionLine *> all_extrusions;
    for (int perimeter_idx = start_perimeter; perimeter_idx != end_perimeter; perimeter_idx += direction) {
        if (perimeters[perimeter_idx].empty())
            continue;
        for (Arachne::ExtrusionLine &wall : perimeters[perimeter_idx])
            all_extrusions.emplace_back(&wall);
    }
 
    // Find topological order with constraints from extrusions_constrains.
    std::vector<size_t>              blocked(all_extrusions.size(), 0); // Value indicating how many extrusions it is blocking (preceding extrusions) an extrusion.
    std::vector<std::vector<size_t>> blocking(all_extrusions.size());   // Each extrusion contains a vector of extrusions that are blocked by this extrusion.
    ankerl::unordered_dense::map<const Arachne::ExtrusionLine *, size_t> map_extrusion_to_idx;
    for (size_t idx = 0; idx < all_extrusions.size(); idx++)
        map_extrusion_to_idx.emplace(all_extrusions[idx], idx);
 
    Arachne::WallToolPaths::ExtrusionLineSet extrusions_constrains = Arachne::WallToolPaths::getRegionOrder(all_extrusions, params.config.external_perimeters_first);
    for (auto [before, after] : extrusions_constrains) {
        auto after_it = map_extrusion_to_idx.find(after);
        ++blocked[after_it->second];
        blocking[map_extrusion_to_idx.find(before)->second].emplace_back(after_it->second);
    }
 
    std::vector<bool> processed(all_extrusions.size(), false);          // Indicate that the extrusion was already processed.
    Point             current_position = all_extrusions.empty() ? Point::Zero() : all_extrusions.front()->junctions.front().p; // Some starting position.
    std::vector<PerimeterGeneratorArachneExtrusion> ordered_extrusions;         // To store our result in. At the end we'll std::swap.
    ordered_extrusions.reserve(all_extrusions.size());
 
    while (ordered_extrusions.size() < all_extrusions.size()) {
        size_t best_candidate    = 0;
        double best_distance_sqr = std::numeric_limits<double>::max();
        bool   is_best_closed    = false;
 
        std::vector<size_t> available_candidates;
        for (size_t candidate = 0; candidate < all_extrusions.size(); ++candidate) {
            if (processed[candidate] || blocked[candidate])
                continue; // Not a valid candidate.
            available_candidates.push_back(candidate);
        }
 
        std::sort(available_candidates.begin(), available_candidates.end(), [&all_extrusions](const size_t a_idx, const size_t b_idx) -> bool {
            return all_extrusions[a_idx]->is_closed < all_extrusions[b_idx]->is_closed;
        });
 
        for (const size_t candidate_path_idx : available_candidates) {
            auto& path = all_extrusions[candidate_path_idx];
 
            if (path->junctions.empty()) { // No vertices in the path. Can't find the start position then or really plan it in. Put that at the end.
                if (best_distance_sqr == std::numeric_limits<double>::max()) {
                    best_candidate = candidate_path_idx;
                    is_best_closed = path->is_closed;
                }
                continue;
            }
 
            const Point candidate_position = path->junctions.front().p;
            double      distance_sqr       = (current_position - candidate_position).cast<double>().norm();
            if (distance_sqr < best_distance_sqr) { // Closer than the best candidate so far.
                if (path->is_closed || (!path->is_closed && best_distance_sqr != std::numeric_limits<double>::max()) || (!path->is_closed && !is_best_closed)) {
                    best_candidate    = candidate_path_idx;
                    best_distance_sqr = distance_sqr;
                    is_best_closed    = path->is_closed;
                }
            }
        }
 
        auto &best_path = all_extrusions[best_candidate];
        ordered_extrusions.push_back({best_path, best_path->is_contour(), false});
        processed[best_candidate] = true;
        for (size_t unlocked_idx : blocking[best_candidate])
            blocked[unlocked_idx]--;
 
        if (!best_path->junctions.empty()) { //If all paths were empty, the best path is still empty. We don't upate the current position then.
            if(best_path->is_closed)
                current_position = best_path->junctions[0].p; //We end where we started.
            else
                current_position = best_path->junctions.back().p; //Pick the other end from where we started.
        }
    }
 
    if (params.layer_id > 0 && params.config.fuzzy_skin != FuzzySkinType::None) {
        std::vector<PerimeterGeneratorArachneExtrusion *> closed_loop_extrusions;
        for (PerimeterGeneratorArachneExtrusion &extrusion : ordered_extrusions)
            if (extrusion.extrusion->inset_idx == 0) {
                if (extrusion.extrusion->is_closed && params.config.fuzzy_skin == FuzzySkinType::External) {
                    closed_loop_extrusions.emplace_back(&extrusion);
                } else {
                    extrusion.fuzzify = true;
                }
            }
 
        if (params.config.fuzzy_skin == FuzzySkinType::External) {
            ClipperLib_Z::Paths loops_paths;
            loops_paths.reserve(closed_loop_extrusions.size());
            for (const auto &cl_extrusion : closed_loop_extrusions) {
                assert(cl_extrusion->extrusion->junctions.front() == cl_extrusion->extrusion->junctions.back());
                size_t             loop_idx = &cl_extrusion - &closed_loop_extrusions.front();
                ClipperLib_Z::Path loop_path;
                loop_path.reserve(cl_extrusion->extrusion->junctions.size() - 1);
                for (auto junction_it = cl_extrusion->extrusion->junctions.begin(); junction_it != std::prev(cl_extrusion->extrusion->junctions.end()); ++junction_it)
                    loop_path.emplace_back(junction_it->p.x(), junction_it->p.y(), loop_idx);
                loops_paths.emplace_back(loop_path);
            }
 
            ClipperLib_Z::Clipper clipper;
            clipper.AddPaths(loops_paths, ClipperLib_Z::ptSubject, true);
            ClipperLib_Z::PolyTree loops_polytree;
            clipper.Execute(ClipperLib_Z::ctUnion, loops_polytree, ClipperLib_Z::pftEvenOdd, ClipperLib_Z::pftEvenOdd);
 
            for (const ClipperLib_Z::PolyNode *child_node : loops_polytree.Childs) {
                // The whole contour must have the same index.
                coord_t polygon_idx  = child_node->Contour.front().z();
                bool    has_same_idx = std::all_of(child_node->Contour.begin(), child_node->Contour.end(),
                                                   [&polygon_idx](const ClipperLib_Z::IntPoint &point) -> bool { return polygon_idx == point.z(); });
                if (has_same_idx)
                    closed_loop_extrusions[polygon_idx]->fuzzify = true;
            }
        }
    }
 
    if (ExtrusionEntityCollection extrusion_coll = traverse_extrusions(params, lower_slices_polygons_cache, ordered_extrusions); !extrusion_coll.empty())
        out_loops.append(extrusion_coll);
 
    ExPolygons    infill_contour = union_ex(wallToolPaths.getInnerContour());
    const coord_t spacing        = (perimeters.size() == 1) ? ext_perimeter_spacing2 : perimeter_spacing;
    if (offset_ex(infill_contour, -float(spacing / 2.)).empty())
        infill_contour.clear(); // Infill region is too small, so let's filter it out.
 
    // create one more offset to be used as boundary for fill
    // we offset by half the perimeter spacing (to get to the actual infill boundary)
    // and then we offset back and forth by half the infill spacing to only consider the
    // non-collapsing regions
    coord_t inset =
        (loop_number < 0) ? 0 :
        (loop_number == 0) ?
                            // one loop
            ext_perimeter_spacing:
            // two or more loops?
            perimeter_spacing;
 
    inset = coord_t(scale_(params.config.get_abs_value("infill_overlap", unscale<double>(inset))));
    Polygons pp;
    for (ExPolygon &ex : infill_contour)
        ex.simplify_p(params.scaled_resolution, &pp);
    // collapse too narrow infill areas
    const auto    min_perimeter_infill_spacing = coord_t(solid_infill_spacing * (1. - INSET_OVERLAP_TOLERANCE));
    // append infill areas to fill_surfaces
    ExPolygons infill_areas =
        offset2_ex(
            union_ex(pp),
            float(- min_perimeter_infill_spacing / 2.),
            float(inset + min_perimeter_infill_spacing / 2.));
 
    if (lower_slices != nullptr && params.config.overhangs && params.config.extra_perimeters_on_overhangs &&
        params.config.perimeters > 0 && params.layer_id > params.object_config.raft_layers) {
        // Generate extra perimeters on overhang areas, and cut them to these parts only, to save print time and material
        auto [extra_perimeters, filled_area] = generate_extra_perimeters_over_overhangs(infill_areas,
                                                                                        lower_slices_polygons_cache,
                                                                                        loop_number + 1,
                                                                                        params.overhang_flow, params.scaled_resolution,
                                                                                        params.object_config, params.print_config);
        if (!extra_perimeters.empty()) {
            ExtrusionEntityCollection &this_islands_perimeters = static_cast<ExtrusionEntityCollection&>(*out_loops.entities.back());
            ExtrusionEntitiesPtr       old_entities;
            old_entities.swap(this_islands_perimeters.entities);
            for (ExtrusionPaths &paths : extra_perimeters) 
                this_islands_perimeters.append(std::move(paths));
            append(this_islands_perimeters.entities, old_entities);
            infill_areas = diff_ex(infill_areas, filled_area);
        }
    }
    
    append(out_fill_expolygons, std::move(infill_areas));
}

Referenced by Slic3r::LayerRegion::make_perimeters().

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◆ process_classic()

void Slic3r::PerimeterGenerator::process_classic	(	const Parameters &	params,
		const Surface &	surface,
		const ExPolygons *	lower_slices,
		Polygons &	lower_slices_polygons_cache,
		ExtrusionEntityCollection &	out_loops,
		ExtrusionEntityCollection &	out_gap_fill,
		ExPolygons &	out_fill_expolygons
	)

{
    // other perimeters
    coord_t perimeter_width         = params.perimeter_flow.scaled_width();
    coord_t perimeter_spacing       = params.perimeter_flow.scaled_spacing();
    // external perimeters
    coord_t ext_perimeter_width     = params.ext_perimeter_flow.scaled_width();
    coord_t ext_perimeter_spacing   = params.ext_perimeter_flow.scaled_spacing();
    coord_t ext_perimeter_spacing2  = scaled<coord_t>(0.5f * (params.ext_perimeter_flow.spacing() + params.perimeter_flow.spacing()));
    // solid infill
    coord_t solid_infill_spacing    = params.solid_infill_flow.scaled_spacing();
    
    // Calculate the minimum required spacing between two adjacent traces.
    // This should be equal to the nominal flow spacing but we experiment
    // with some tolerance in order to avoid triggering medial axis when
    // some squishing might work. Loops are still spaced by the entire
    // flow spacing; this only applies to collapsing parts.
    // For ext_min_spacing we use the ext_perimeter_spacing calculated for two adjacent
    // external loops (which is the correct way) instead of using ext_perimeter_spacing2
    // which is the spacing between external and internal, which is not correct
    // and would make the collapsing (thus the details resolution) dependent on 
    // internal flow which is unrelated.
    coord_t min_spacing         = coord_t(perimeter_spacing      * (1 - INSET_OVERLAP_TOLERANCE));
    coord_t ext_min_spacing     = coord_t(ext_perimeter_spacing  * (1 - INSET_OVERLAP_TOLERANCE));
    bool    has_gap_fill    = params.config.gap_fill_enabled.value && params.config.gap_fill_speed.value > 0;
 
    // prepare grown lower layer slices for overhang detection
    if (params.config.overhangs && lower_slices != nullptr && lower_slices_polygons_cache.empty()) {
        // We consider overhang any part where the entire nozzle diameter is not supported by the
        // lower layer, so we take lower slices and offset them by half the nozzle diameter used 
        // in the current layer
        double nozzle_diameter = params.print_config.nozzle_diameter.get_at(params.config.perimeter_extruder-1);
        lower_slices_polygons_cache = offset(*lower_slices, float(scale_(+nozzle_diameter/2)));
    }
 
    // we need to process each island separately because we might have different
    // extra perimeters for each one
    // detect how many perimeters must be generated for this island
    int        loop_number = params.config.perimeters + surface.extra_perimeters - 1;  // 0-indexed loops
    ExPolygons last        = union_ex(surface.expolygon.simplify_p(params.scaled_resolution));
    ExPolygons gaps;
    if (loop_number >= 0) {
        // In case no perimeters are to be generated, loop_number will equal to -1.
        std::vector<PerimeterGeneratorLoops> contours(loop_number+1);    // depth => loops
        std::vector<PerimeterGeneratorLoops> holes(loop_number+1);       // depth => loops
        ThickPolylines thin_walls;
        // we loop one time more than needed in order to find gaps after the last perimeter was applied
        for (int i = 0;; ++ i) {  // outer loop is 0
            // Calculate next onion shell of perimeters.
            ExPolygons offsets;
            if (i == 0) {
                // the minimum thickness of a single loop is:
                // ext_width/2 + ext_spacing/2 + spacing/2 + width/2
                offsets = params.config.thin_walls ? 
                    offset2_ex(
                        last,
                        - float(ext_perimeter_width / 2. + ext_min_spacing / 2. - 1),
                        + float(ext_min_spacing / 2. - 1)) :
                    offset_ex(last, - float(ext_perimeter_width / 2.));
                // look for thin walls
                if (params.config.thin_walls) {
                    // the following offset2 ensures almost nothing in @thin_walls is narrower than $min_width
                    // (actually, something larger than that still may exist due to mitering or other causes)
                    coord_t min_width = coord_t(scale_(params.ext_perimeter_flow.nozzle_diameter() / 3));
                    ExPolygons expp = opening_ex(
                        // medial axis requires non-overlapping geometry
                        diff_ex(last, offset(offsets, float(ext_perimeter_width / 2.) + ClipperSafetyOffset)),
                        float(min_width / 2.));
                    // the maximum thickness of our thin wall area is equal to the minimum thickness of a single loop
                    for (ExPolygon &ex : expp)
                        ex.medial_axis(min_width, ext_perimeter_width + ext_perimeter_spacing2, &thin_walls);
                }
                if (params.spiral_vase && offsets.size() > 1) {
                  // Remove all but the largest area polygon.
                  keep_largest_contour_only(offsets);
                }
            } else {
                //FIXME Is this offset correct if the line width of the inner perimeters differs
                // from the line width of the infill?
                coord_t distance = (i == 1) ? ext_perimeter_spacing2 : perimeter_spacing;
                offsets = params.config.thin_walls ?
                    // This path will ensure, that the perimeters do not overfill, as in 
                    // prusa3d/Slic3r GH #32, but with the cost of rounding the perimeters
                    // excessively, creating gaps, which then need to be filled in by the not very 
                    // reliable gap fill algorithm.
                    // Also the offset2(perimeter, -x, x) may sometimes lead to a perimeter, which is larger than
                    // the original.
                    offset2_ex(last,
                            - float(distance + min_spacing / 2. - 1.),
                            float(min_spacing / 2. - 1.)) :
                    // If "detect thin walls" is not enabled, this paths will be entered, which 
                    // leads to overflows, as in prusa3d/Slic3r GH #32
                    offset_ex(last, - float(distance));
                // look for gaps
                if (has_gap_fill)
                    // not using safety offset here would "detect" very narrow gaps
                    // (but still long enough to escape the area threshold) that gap fill
                    // won't be able to fill but we'd still remove from infill area
                    append(gaps, diff_ex(
                        offset(last,    - float(0.5 * distance)),
                        offset(offsets,   float(0.5 * distance + 10))));  // safety offset
            }
            if (offsets.empty()) {
                // Store the number of loops actually generated.
                loop_number = i - 1;
                // No region left to be filled in.
                last.clear();
                break;
            } else if (i > loop_number) {
                // If i > loop_number, we were looking just for gaps.
                break;
            }
            {
                const bool fuzzify_contours = params.config.fuzzy_skin != FuzzySkinType::None && i == 0 && params.layer_id > 0;
                const bool fuzzify_holes    = fuzzify_contours && params.config.fuzzy_skin == FuzzySkinType::All;
                for (const ExPolygon &expolygon : offsets) {
                  // Outer contour may overlap with an inner contour,
                  // inner contour may overlap with another inner contour,
                  // outer contour may overlap with itself.
                  //FIXME evaluate the overlaps, annotate each point with an overlap depth,
                    // compensate for the depth of intersection.
                    contours[i].emplace_back(expolygon.contour, i, true, fuzzify_contours);
 
                    if (! expolygon.holes.empty()) {
                        holes[i].reserve(holes[i].size() + expolygon.holes.size());
                        for (const Polygon &hole : expolygon.holes)
                            holes[i].emplace_back(hole, i, false, fuzzify_holes);
                    }
                }
            }
            last = std::move(offsets);
            if (i == loop_number && (! has_gap_fill || params.config.fill_density.value == 0)) {
              // The last run of this loop is executed to collect gaps for gap fill.
              // As the gap fill is either disabled or not 
              break;
            }
        }
 
        // nest loops: holes first
        for (int d = 0; d <= loop_number; ++ d) {
            PerimeterGeneratorLoops &holes_d = holes[d];
            // loop through all holes having depth == d
            for (int i = 0; i < (int)holes_d.size(); ++ i) {
                const PerimeterGeneratorLoop &loop = holes_d[i];
                // find the hole loop that contains this one, if any
                for (int t = d + 1; t <= loop_number; ++ t) {
                    for (int j = 0; j < (int)holes[t].size(); ++ j) {
                        PerimeterGeneratorLoop &candidate_parent = holes[t][j];
                        if (candidate_parent.polygon.contains(loop.polygon.first_point())) {
                            candidate_parent.children.push_back(loop);
                            holes_d.erase(holes_d.begin() + i);
                            -- i;
                            goto NEXT_LOOP;
                        }
                    }
                }
                // if no hole contains this hole, find the contour loop that contains it
                for (int t = loop_number; t >= 0; -- t) {
                    for (int j = 0; j < (int)contours[t].size(); ++ j) {
                        PerimeterGeneratorLoop &candidate_parent = contours[t][j];
                        if (candidate_parent.polygon.contains(loop.polygon.first_point())) {
                            candidate_parent.children.push_back(loop);
                            holes_d.erase(holes_d.begin() + i);
                            -- i;
                            goto NEXT_LOOP;
                        }
                    }
                }
                NEXT_LOOP: ;
            }
        }
        // nest contour loops
        for (int d = loop_number; d >= 1; -- d) {
            PerimeterGeneratorLoops &contours_d = contours[d];
            // loop through all contours having depth == d
            for (int i = 0; i < (int)contours_d.size(); ++ i) {
                const PerimeterGeneratorLoop &loop = contours_d[i];
                // find the contour loop that contains it
                for (int t = d - 1; t >= 0; -- t) {
                    for (size_t j = 0; j < contours[t].size(); ++ j) {
                        PerimeterGeneratorLoop &candidate_parent = contours[t][j];
                        if (candidate_parent.polygon.contains(loop.polygon.first_point())) {
                            candidate_parent.children.push_back(loop);
                            contours_d.erase(contours_d.begin() + i);
                            -- i;
                            goto NEXT_CONTOUR;
                        }
                    }
                }
                NEXT_CONTOUR: ;
            }
        }
        // at this point, all loops should be in contours[0]
        ExtrusionEntityCollection entities = traverse_loops_classic(params, lower_slices_polygons_cache, contours.front(), thin_walls);
        // if brim will be printed, reverse the order of perimeters so that
        // we continue inwards after having finished the brim
        // TODO: add test for perimeter order
        if (params.config.external_perimeters_first || 
            (params.layer_id == 0 && params.object_config.brim_width.value > 0))
            entities.reverse();
        // append perimeters for this slice as a collection
        if (! entities.empty())
            out_loops.append(entities);
    } // for each loop of an island
 
    // fill gaps
    if (! gaps.empty()) {
        // collapse 
        double min = 0.2 * perimeter_width * (1 - INSET_OVERLAP_TOLERANCE);
        double max = 2. * perimeter_spacing;
        ExPolygons gaps_ex = diff_ex(
            //FIXME offset2 would be enough and cheaper.
            opening_ex(gaps, float(min / 2.)),
            offset2_ex(gaps, - float(max / 2.), float(max / 2. + ClipperSafetyOffset)));
        ThickPolylines polylines;
        for (const ExPolygon &ex : gaps_ex)
            ex.medial_axis(min, max, &polylines);
        if (! polylines.empty()) {
      ExtrusionEntityCollection gap_fill;
      variable_width_classic(polylines, ExtrusionRole::GapFill, params.solid_infill_flow, gap_fill.entities);
            /*  Make sure we don't infill narrow parts that are already gap-filled
                (we only consider this surface's gaps to reduce the diff() complexity).
                Growing actual extrusions ensures that gaps not filled by medial axis
                are not subtracted from fill surfaces (they might be too short gaps
                that medial axis skips but infill might join with other infill regions
                and use zigzag).  */
            //FIXME Vojtech: This grows by a rounded extrusion width, not by line spacing,
            // therefore it may cover the area, but no the volume.
            last = diff_ex(last, gap_fill.polygons_covered_by_width(10.f));
      out_gap_fill.append(std::move(gap_fill.entities));
    }
    }
 
    // create one more offset to be used as boundary for fill
    // we offset by half the perimeter spacing (to get to the actual infill boundary)
    // and then we offset back and forth by half the infill spacing to only consider the
    // non-collapsing regions
    coord_t inset = 
        (loop_number < 0) ? 0 :
        (loop_number == 0) ?
            // one loop
            ext_perimeter_spacing / 2 :
            // two or more loops?
            perimeter_spacing / 2;
    // only apply infill overlap if we actually have one perimeter
    if (inset > 0)
        inset -= coord_t(scale_(params.config.get_abs_value("infill_overlap", unscale<double>(inset + solid_infill_spacing / 2))));
    // simplify infill contours according to resolution
    Polygons pp;
    for (ExPolygon &ex : last)
        ex.simplify_p(params.scaled_resolution, &pp);
    // collapse too narrow infill areas
    coord_t min_perimeter_infill_spacing = coord_t(solid_infill_spacing * (1. - INSET_OVERLAP_TOLERANCE));
    // append infill areas to fill_surfaces
    ExPolygons infill_areas =
        offset2_ex(
            union_ex(pp),
            float(- inset - min_perimeter_infill_spacing / 2.),
            float(min_perimeter_infill_spacing / 2.));
 
    if (lower_slices != nullptr && params.config.overhangs && params.config.extra_perimeters_on_overhangs &&
        params.config.perimeters > 0 && params.layer_id > params.object_config.raft_layers) {
        // Generate extra perimeters on overhang areas, and cut them to these parts only, to save print time and material
        auto [extra_perimeters, filled_area] = generate_extra_perimeters_over_overhangs(infill_areas,
                                                                                        lower_slices_polygons_cache,
                                                                                        loop_number + 1,
                                                                                        params.overhang_flow, params.scaled_resolution,
                                                                                        params.object_config, params.print_config);
        if (!extra_perimeters.empty()) {
            ExtrusionEntityCollection &this_islands_perimeters = static_cast<ExtrusionEntityCollection&>(*out_loops.entities.back());
            ExtrusionEntitiesPtr       old_entities;
            old_entities.swap(this_islands_perimeters.entities);
            for (ExtrusionPaths &paths : extra_perimeters) 
                this_islands_perimeters.append(std::move(paths));
            append(this_islands_perimeters.entities, old_entities);
            infill_areas = diff_ex(infill_areas, filled_area);
        }
    }
    
    append(out_fill_expolygons, std::move(infill_areas));
}

References Slic3r::All, Slic3r::ExtrusionEntityCollection::append(), Slic3r::append(), Slic3r::PerimeterGeneratorLoop::children, Slic3r::ClipperSafetyOffset, Slic3r::PerimeterGenerator::Parameters::config, Slic3r::Polygon::contains(), Slic3r::diff_ex(), Slic3r::ExtrusionEntityCollection::empty(), Slic3r::ExtrusionEntityCollection::entities, Slic3r::Surface::expolygon, Slic3r::PerimeterGenerator::Parameters::ext_perimeter_flow, Slic3r::Surface::extra_perimeters, Slic3r::ExtrusionRole::GapFill, Slic3r::generate_extra_perimeters_over_overhangs(), Slic3r::holes(), INSET_OVERLAP_TOLERANCE, Slic3r::keep_largest_contour_only(), Slic3r::PerimeterGenerator::Parameters::layer_id, Slic3r::None, Slic3r::Flow::nozzle_diameter(), Slic3r::PerimeterGenerator::Parameters::object_config, Slic3r::offset(), Slic3r::offset2_ex(), Slic3r::offset_ex(), Slic3r::opening_ex(), Slic3r::PerimeterGenerator::Parameters::overhang_flow, Slic3r::PerimeterGenerator::Parameters::perimeter_flow, Slic3r::PerimeterGeneratorLoop::polygon, Slic3r::ExtrusionEntityCollection::polygons_covered_by_width(), Slic3r::PerimeterGenerator::Parameters::print_config, Slic3r::ExtrusionEntityCollection::reverse(), scale_, Slic3r::PerimeterGenerator::Parameters::scaled_resolution, Slic3r::Flow::scaled_spacing(), Slic3r::Flow::scaled_width(), Slic3r::ExPolygon::simplify_p(), Slic3r::PerimeterGenerator::Parameters::solid_infill_flow, Slic3r::Flow::spacing(), Slic3r::PerimeterGenerator::Parameters::spiral_vase, Slic3r::ExtrusionEntityCollection::swap(), Slic3r::thin_walls(), Slic3r::traverse_loops_classic(), Slic3r::union_ex(), and Slic3r::variable_width_classic().

Referenced by Slic3r::LayerRegion::make_perimeters().

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◆ thick_polyline_to_multi_path()

ExtrusionMultiPath Slic3r::PerimeterGenerator::thick_polyline_to_multi_path	(	const ThickPolyline &	thick_polyline,
		ExtrusionRole	role,
		const Flow &	flow,
		float	tolerance,
		float	merge_tolerance
	)

{
    ExtrusionMultiPath multi_path;
    ExtrusionPath      path(role);
    ThickLines         lines = thick_polyline.thicklines();
 
    for (int i = 0; i < (int)lines.size(); ++i) {
        const ThickLine& line = lines[i];
        assert(line.a_width >= SCALED_EPSILON && line.b_width >= SCALED_EPSILON);
 
        const coordf_t line_len = line.length();
        if (line_len < SCALED_EPSILON) {
            // The line is so tiny that we don't care about its width when we connect it to another line.
            if (!path.empty())
                path.polyline.points.back() = line.b; // If the variable path is non-empty, connect this tiny line to it.
            else if (i + 1 < (int)lines.size()) // If there is at least one following line, connect this tiny line to it.
                lines[i + 1].a = line.a;
            else if (!multi_path.paths.empty())
                multi_path.paths.back().polyline.points.back() = line.b; // Connect this tiny line to the last finished path.
 
            // If any of the above isn't satisfied, then remove this tiny line.
            continue;
        }
 
        double thickness_delta = fabs(line.a_width - line.b_width);
        if (thickness_delta > tolerance) {
            const auto segments = (unsigned int)ceil(thickness_delta / tolerance);
            const coordf_t seg_len = line_len / segments;
            Points pp;
            std::vector<coordf_t> width;
            {
                pp.push_back(line.a);
                width.push_back(line.a_width);
                for (size_t j = 1; j < segments; ++j) {
                    pp.push_back((line.a.cast<double>() + (line.b - line.a).cast<double>().normalized() * (j * seg_len)).cast<coord_t>());
 
                    coordf_t w = line.a_width + (j*seg_len) * (line.b_width-line.a_width) / line_len;
                    width.push_back(w);
                    width.push_back(w);
                }
                pp.push_back(line.b);
                width.push_back(line.b_width);
 
                assert(pp.size() == segments + 1u);
                assert(width.size() == segments*2);
            }
 
            // delete this line and insert new ones
            lines.erase(lines.begin() + i);
            for (size_t j = 0; j < segments; ++j) {
                ThickLine new_line(pp[j], pp[j+1]);
                new_line.a_width = width[2*j];
                new_line.b_width = width[2*j+1];
                lines.insert(lines.begin() + i + j, new_line);
            }
 
            -- i;
            continue;
        }
 
        const double w        = fmax(line.a_width, line.b_width);
        const Flow   new_flow = (role.is_bridge() && flow.bridge()) ? flow : flow.with_width(unscale<float>(w) + flow.height() * float(1. - 0.25 * PI));
        if (path.polyline.points.empty()) {
            path.polyline.append(line.a);
            path.polyline.append(line.b);
            // Convert from spacing to extrusion width based on the extrusion model
            // of a square extrusion ended with semi circles.
            #ifdef SLIC3R_DEBUG
            printf("  filling %f gap\n", flow.width);
            #endif
            path.mm3_per_mm  = new_flow.mm3_per_mm();
            path.width       = new_flow.width();
            path.height      = new_flow.height();
        } else {
            assert(path.width >= EPSILON);
            thickness_delta = scaled<double>(fabs(path.width - new_flow.width()));
            if (thickness_delta <= merge_tolerance) {
                // the width difference between this line and the current flow
                // (of the previous line) width is within the accepted tolerance
                path.polyline.append(line.b);
            } else {
                // we need to initialize a new line
                multi_path.paths.emplace_back(std::move(path));
                path = ExtrusionPath(role);
                -- i;
            }
        }
    }
    if (path.polyline.is_valid())
        multi_path.paths.emplace_back(std::move(path));
    return multi_path;
}

References Slic3r::Line::a, Slic3r::ThickLine::a_width, Slic3r::Polyline::append(), Slic3r::Line::b, Slic3r::ThickLine::b_width, Slic3r::Flow::bridge(), ceil(), Slic3r::ExtrusionPath::empty(), EPSILON, Slic3r::ExtrusionPath::height, Slic3r::Flow::height(), Slic3r::ExtrusionRole::is_bridge(), Slic3r::MultiPoint::is_valid(), Slic3r::Line::length(), Slic3r::ExtrusionPath::mm3_per_mm, Slic3r::Flow::mm3_per_mm(), Slic3r::ExtrusionMultiPath::paths, PI, Slic3r::MultiPoint::points, Slic3r::ExtrusionPath::polyline, SCALED_EPSILON, Slic3r::ThickPolyline::thicklines(), Slic3r::ExtrusionPath::width, Slic3r::Flow::width(), and Slic3r::Flow::with_width().

Referenced by Slic3r::extrusion_paths_append(), Slic3r::extrusion_paths_append(), and Slic3r::variable_width_classic().

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Classes

Functions

Function Documentation

◆ process_arachne()

◆ process_classic()

◆ thick_polyline_to_multi_path()