bool
ExPolygonCollection::contains_b(const Point &point) const
{
    for (ExPolygons::const_iterator it = this->expolygons.begin(); it != this->expolygons.end(); ++it) {
        if (it->contains_b(point)) return true;
    }
    return false;
}

void
MotionPlanner::shortest_path(const Point &from, const Point &to, Polyline* polyline)
{
    if (!this->initialized) this->initialize();
    
    if (this->islands.empty()) {
        polyline->points.push_back(from);
        polyline->points.push_back(to);
        return;
    }
    
    // Are both points in the same island?
    int island_idx = -1;
    for (ExPolygons::const_iterator island = this->islands.begin(); island != this->islands.end(); ++island) {
        if (island->contains(from) && island->contains(to)) {
            // since both points are in the same island, is a direct move possible?
            // if so, we avoid generating the visibility environment
            if (island->contains(Line(from, to))) {
                polyline->points.push_back(from);
                polyline->points.push_back(to);
                return;
            }
            island_idx = island - this->islands.begin();
            break;
        }
    }
    
    // Now check whether points are inside the environment.
    Point inner_from    = from;
    Point inner_to      = to;
    bool from_is_inside, to_is_inside;
    if (island_idx == -1) {
        if (!(from_is_inside = this->outer.contains(from))) {
            // Find the closest inner point to start from.
            from.nearest_point(this->outer, &inner_from);
        }
        if (!(to_is_inside = this->outer.contains(to))) {
            // Find the closest inner point to start from.
            to.nearest_point(this->outer, &inner_to);
        }
    } else {
        if (!(from_is_inside = this->inner[island_idx].contains(from))) {
            // Find the closest inner point to start from.
            from.nearest_point(this->inner[island_idx], &inner_from);
        }
        if (!(to_is_inside = this->inner[island_idx].contains(to))) {
            // Find the closest inner point to start from.
            to.nearest_point(this->inner[island_idx], &inner_to);
        }
    }
    
    // perform actual path search
    MotionPlannerGraph* graph = this->init_graph(island_idx);
    graph->shortest_path(graph->find_node(inner_from), graph->find_node(inner_to), polyline);
    
    polyline->points.insert(polyline->points.begin(), from);
    polyline->points.push_back(to);
}

MotionPlanner::MotionPlanner(const ExPolygons &islands)
    : initialized(false)
{
    ExPolygons expp;
    for (ExPolygons::const_iterator island = islands.begin(); island != islands.end(); ++island)
        island->simplify(SCALED_EPSILON, &expp);
    
    for (ExPolygons::const_iterator island = expp.begin(); island != expp.end(); ++island)
        this->islands.push_back(MotionPlannerEnv(*island));
}

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;
}

void
MotionPlanner::initialize()
{
    if (this->initialized) return;
    if (this->islands.empty()) return;  // prevent initialization of empty BoundingBox
    
    ExPolygons expp;
    for (ExPolygons::const_iterator island = this->islands.begin(); island != this->islands.end(); ++island) {
        island->simplify(SCALED_EPSILON, expp);
    }
    this->islands = expp;
    
    // loop through islands in order to create inner expolygons and collect their contours
    this->inner.reserve(this->islands.size());
    Polygons outer_holes;
    for (ExPolygons::const_iterator island = this->islands.begin(); island != this->islands.end(); ++island) {
        this->inner.push_back(ExPolygonCollection());
        offset(*island, &this->inner.back().expolygons, -MP_INNER_MARGIN);
        
        outer_holes.push_back(island->contour);
    }
    
    // grow island contours in order to prepare holes of the outer environment
    // This is actually wrong because it might merge contours that are close,
    // thus confusing the island check in shortest_path() below
    //offset(outer_holes, &outer_holes, +MP_OUTER_MARGIN);
    
    // generate outer contour as bounding box of everything
    Points points;
    for (Polygons::const_iterator contour = outer_holes.begin(); contour != outer_holes.end(); ++contour)
        points.insert(points.end(), contour->points.begin(), contour->points.end());
    BoundingBox bb(points);
    
    // grow outer contour
    Polygons contour;
    offset(bb.polygon(), &contour, +MP_OUTER_MARGIN);
    assert(contour.size() == 1);
    
    // make expolygon for outer environment
    ExPolygons outer;
    diff(contour, outer_holes, &outer);
    assert(outer.size() == 1);
    this->outer = outer.front();
    
    this->graphs.resize(this->islands.size() + 1, NULL);
    this->initialized = true;
}

void
PerimeterGenerator::process()
{
    // other perimeters
    this->_mm3_per_mm           = this->perimeter_flow.mm3_per_mm();
    coord_t pwidth              = this->perimeter_flow.scaled_width();
    coord_t pspacing            = this->perimeter_flow.scaled_spacing();
    
    // external perimeters
    this->_ext_mm3_per_mm       = this->ext_perimeter_flow.mm3_per_mm();
    coord_t ext_pwidth          = this->ext_perimeter_flow.scaled_width();
    coord_t ext_pspacing        = this->ext_perimeter_flow.scaled_spacing();
    coord_t ext_pspacing2       = this->ext_perimeter_flow.scaled_spacing(this->perimeter_flow);
    
    // overhang perimeters
    this->_mm3_per_mm_overhang  = this->overhang_flow.mm3_per_mm();
    
    // solid infill
    coord_t ispacing            = this->solid_infill_flow.scaled_spacing();
    coord_t gap_area_threshold  = pwidth * pwidth;
    
    // 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_pspacing calculated for two adjacent
    // external loops (which is the correct way) instead of using ext_pspacing2
    // 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         = pspacing      * (1 - INSET_OVERLAP_TOLERANCE);
    coord_t ext_min_spacing     = ext_pspacing  * (1 - INSET_OVERLAP_TOLERANCE);
    
    // prepare grown lower layer slices for overhang detection
    if (this->lower_slices != NULL && this->config->overhangs) {
        // 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 = this->print_config->nozzle_diameter.get_at(this->config->perimeter_extruder-1);
        
        this->_lower_slices_p = offset(*this->lower_slices, scale_(+nozzle_diameter/2));
    }
    
    // we need to process each island separately because we might have different
    // extra perimeters for each one
    for (Surfaces::const_iterator surface = this->slices->surfaces.begin();
        surface != this->slices->surfaces.end(); ++surface) {
        // detect how many perimeters must be generated for this island
        signed short loop_number = this->config->perimeters + surface->extra_perimeters;
        loop_number--;  // 0-indexed loops
        
        Polygons gaps;
        
        Polygons last = surface->expolygon.simplify_p(SCALED_RESOLUTION);
        if (loop_number >= 0) {  // no loops = -1
            
            std::vector<PerimeterGeneratorLoops> contours(loop_number+1);    // depth => loops
            std::vector<PerimeterGeneratorLoops> holes(loop_number+1);       // depth => loops
            Polylines thin_walls;
            
            // we loop one time more than needed in order to find gaps after the last perimeter was applied
            for (signed short i = 0; i <= loop_number+1; ++i) {  // outer loop is 0
                Polygons offsets;
                if (i == 0) {
                    // the minimum thickness of a single loop is:
                    // ext_width/2 + ext_spacing/2 + spacing/2 + width/2
                    if (this->config->thin_walls) {
                        offsets = offset2(
                            last,
                            -(ext_pwidth/2 + ext_min_spacing/2 - 1),
                            +(ext_min_spacing/2 - 1)
                        );
                    } else {
                        offsets = offset(last, -ext_pwidth/2);
                    }
                    
                    // look for thin walls
                    if (this->config->thin_walls) {
                        Polygons diffpp = diff(
                            last,
                            offset(offsets, +ext_pwidth/2),
                            true  // medial axis requires non-overlapping geometry
                        );
                        
                        // 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 = ext_pwidth / 2;
                        ExPolygons expp = offset2_ex(diffpp, -min_width/2, +min_width/2);
                        
                        // the maximum thickness of our thin wall area is equal to the minimum thickness of a single loop
                        Polylines pp;
                        for (ExPolygons::const_iterator ex = expp.begin(); ex != expp.end(); ++ex)
                            ex->medial_axis(ext_pwidth + ext_pspacing2, min_width, &pp);
                        
                        double threshold = ext_pwidth * 2;
                        for (Polylines::const_iterator p = pp.begin(); p != pp.end(); ++p) {
                            if (p->length() > threshold) {
                                thin_walls.push_back(*p);
                            }
//.........这里部分代码省略.........

Polyline
MotionPlanner::shortest_path(const Point &from, const Point &to)
{
    // lazy generation of configuration space
    if (!this->initialized) this->initialize();
    
    // if we have an empty configuration space, return a straight move
    if (this->islands.empty()) {
        Polyline p;
        p.points.push_back(from);
        p.points.push_back(to);
        return p;
    }
    
    // Are both points in the same island?
    int island_idx = -1;
    for (ExPolygons::const_iterator island = this->islands.begin(); island != this->islands.end(); ++island) {
        if (island->contains(from) && island->contains(to)) {
            // since both points are in the same island, is a direct move possible?
            // if so, we avoid generating the visibility environment
            if (island->contains(Line(from, to))) {
                Polyline p;
                p.points.push_back(from);
                p.points.push_back(to);
                return p;
            }
            island_idx = island - this->islands.begin();
            break;
        }
    }
    
    // get environment
    ExPolygonCollection env = this->get_env(island_idx);
    if (env.expolygons.empty()) {
        // if this environment is empty (probably because it's too small), perform straight move
        // and avoid running the algorithms on empty dataset
        Polyline p;
        p.points.push_back(from);
        p.points.push_back(to);
        return p; // bye bye
    }
    
    // Now check whether points are inside the environment.
    Point inner_from    = from;
    Point inner_to      = to;

    if (!env.contains(from)) {
        // Find the closest inner point to start from.
        inner_from = this->nearest_env_point(env, from, to);
    }
    if (!env.contains(to)) {
        // Find the closest inner point to start from.
        inner_to = this->nearest_env_point(env, to, inner_from);
    }
    
    // perform actual path search
    MotionPlannerGraph* graph = this->init_graph(island_idx);
    Polyline polyline = graph->shortest_path(graph->find_node(inner_from), graph->find_node(inner_to));
    
    polyline.points.insert(polyline.points.begin(), from);
    polyline.points.push_back(to);
    
    {
        // grow our environment slightly in order for simplify_by_visibility()
        // to work best by considering moves on boundaries valid as well
        ExPolygonCollection grown_env;
        offset(env, &grown_env.expolygons, +SCALED_EPSILON);
        
        // remove unnecessary vertices
        polyline.simplify_by_visibility(grown_env);
    }
    
    /*
        SVG svg("shortest_path.svg");
        svg.draw(this->outer);
        svg.arrows = false;
        for (MotionPlannerGraph::adjacency_list_t::const_iterator it = graph->adjacency_list.begin(); it != graph->adjacency_list.end(); ++it) {
            Point a = graph->nodes[it - graph->adjacency_list.begin()];
            for (std::vector<MotionPlannerGraph::neighbor>::const_iterator n = it->begin(); n != it->end(); ++n) {
                Point b = graph->nodes[n->target];
                svg.draw(Line(a, b));
            }
        }
        svg.arrows = true;
        svg.draw(from);
        svg.draw(inner_from, "red");
        svg.draw(to);
        svg.draw(inner_to, "red");
        svg.draw(*polyline, "red");
        svg.Close();
    */
    
    return polyline;
}

void
BridgeDetector::coverage(double angle, Polygons* coverage) const
{
    // Clone our expolygon and rotate it so that we work with vertical lines.
    ExPolygon expolygon = this->expolygon;
    expolygon.rotate(PI/2.0 - angle, Point(0,0));

    /*  Outset the bridge expolygon by half the amount we used for detecting anchors;
        we'll use this one to generate our trapezoids and be sure that their vertices
        are inside the anchors and not on their contours leading to false negatives. */
    ExPolygons grown;
    offset(expolygon, &grown, this->extrusion_width/2.0);

    // Compute trapezoids according to a vertical orientation
    Polygons trapezoids;
    for (ExPolygons::const_iterator it = grown.begin(); it != grown.end(); ++it)
        it->get_trapezoids2(&trapezoids, PI/2.0);

    // get anchors, convert them to Polygons and rotate them too
    Polygons anchors;
    for (ExPolygons::const_iterator anchor = this->_anchors.begin(); anchor != this->_anchors.end(); ++anchor) {
        Polygons pp = *anchor;
        for (Polygons::iterator p = pp.begin(); p != pp.end(); ++p)
            p->rotate(PI/2.0 - angle, Point(0,0));
        anchors.insert(anchors.end(), pp.begin(), pp.end());
    }

    Polygons covered;
    for (Polygons::const_iterator trapezoid = trapezoids.begin(); trapezoid != trapezoids.end(); ++trapezoid) {
        Lines lines = trapezoid->lines();
        Lines supported;
        intersection(lines, anchors, &supported);

        // not nice, we need a more robust non-numeric check
        for (size_t i = 0; i < supported.size(); ++i) {
            if (supported[i].length() < this->extrusion_width) {
                supported.erase(supported.begin() + i);
                i--;
            }
        }

        if (supported.size() >= 2) covered.push_back(*trapezoid);
    }

    // merge trapezoids and rotate them back
    Polygons _coverage;
    union_(covered, &_coverage);
    for (Polygons::iterator p = _coverage.begin(); p != _coverage.end(); ++p)
        p->rotate(-(PI/2.0 - angle), Point(0,0));

    // intersect trapezoids with actual bridge area to remove extra margins
    // and append it to result
    intersection(_coverage, this->expolygon, coverage);

    /*
    if (0) {
        my @lines = map @{$_->lines}, @$trapezoids;
        $_->rotate(-(PI/2 - $angle), [0,0]) for @lines;

        require "Slic3r/SVG.pm";
        Slic3r::SVG::output(
            "coverage_" . rad2deg($angle) . ".svg",
            expolygons          => [$self->expolygon],
            green_expolygons    => $self->_anchors,
            red_expolygons      => $coverage,
            lines               => \@lines,
        );
    }
    */
}

void
SLAPrint::write_svg(const std::string &outputfile) const
{
    const Sizef3 size = this->bb.size();
    const double support_material_radius = sm_pillars_radius();
    
    FILE* f = fopen(outputfile.c_str(), "w");
    fprintf(f,
        "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n"
        "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" \"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd\">\n"
        "<svg width=\"%f\" height=\"%f\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:svg=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" xmlns:slic3r=\"http://slic3r.org/namespaces/slic3r\" viewport-fill=\"black\">\n"
        "<!-- Generated using Slic3r %s http://slic3r.org/ -->\n"
        , size.x, size.y, SLIC3R_VERSION);
    
    for (size_t i = 0; i < this->layers.size(); ++i) {
        const Layer &layer = this->layers[i];
        fprintf(f,
            "\t<g id=\"layer%zu\" slic3r:z=\"%0.4f\" slic3r:slice-z=\"%0.4f\" slic3r:layer-height=\"%0.4f\">\n",
            i,
            layer.print_z,
            layer.slice_z,
            layer.print_z - ((i == 0) ? 0. : this->layers[i-1].print_z)
        );
        
        if (layer.solid) {
            const ExPolygons &slices = layer.slices.expolygons;
            for (ExPolygons::const_iterator it = slices.begin(); it != slices.end(); ++it) {
                std::string pd = this->_SVG_path_d(*it);
                
                fprintf(f,"\t\t<path d=\"%s\" style=\"fill: %s; stroke: %s; stroke-width: %s; fill-type: evenodd\" slic3r:area=\"%0.4f\" />\n",
                    pd.c_str(), "white", "black", "0", unscale(unscale(it->area()))
                );
            }
        } else {
            // Perimeters.
            for (ExPolygons::const_iterator it = layer.perimeters.expolygons.begin();
                it != layer.perimeters.expolygons.end(); ++it) {
                std::string pd = this->_SVG_path_d(*it);
                
                fprintf(f,"\t\t<path d=\"%s\" style=\"fill: %s; stroke: %s; stroke-width: %s; fill-type: evenodd\" slic3r:type=\"perimeter\" />\n",
                    pd.c_str(), "white", "black", "0"
                );
            }
            
            // Solid infill.
            for (ExPolygons::const_iterator it = layer.solid_infill.expolygons.begin();
                it != layer.solid_infill.expolygons.end(); ++it) {
                std::string pd = this->_SVG_path_d(*it);
                
                fprintf(f,"\t\t<path d=\"%s\" style=\"fill: %s; stroke: %s; stroke-width: %s; fill-type: evenodd\" slic3r:type=\"infill\" />\n",
                    pd.c_str(), "white", "black", "0"
                );
            }
            
            // Internal infill.
            for (ExtrusionEntitiesPtr::const_iterator it = layer.infill.entities.begin();
                it != layer.infill.entities.end(); ++it) {
                const ExPolygons infill = union_ex((*it)->grow());
                
                for (ExPolygons::const_iterator e = infill.begin(); e != infill.end(); ++e) {
                    std::string pd = this->_SVG_path_d(*e);
                
                    fprintf(f,"\t\t<path d=\"%s\" style=\"fill: %s; stroke: %s; stroke-width: %s; fill-type: evenodd\" slic3r:type=\"infill\" />\n",
                        pd.c_str(), "white", "black", "0"
                    );
                }
            }
        }
        
        // don't print support material in raft layers
        if (i >= (size_t)this->config.raft_layers) {
            // look for support material pillars belonging to this layer
            for (std::vector<SupportPillar>::const_iterator it = this->sm_pillars.begin(); it != this->sm_pillars.end(); ++it) {
                if (!(it->top_layer >= i && it->bottom_layer <= i)) continue;
            
                // generate a conic tip
                float radius = fminf(
                    support_material_radius,
                    (it->top_layer - i + 1) * this->config.layer_height.value
                );
            
                fprintf(f,"\t\t<circle cx=\"%f\" cy=\"%f\" r=\"%f\" stroke-width=\"0\" fill=\"white\" slic3r:type=\"support\" />\n",
                    unscale(it->x) - this->bb.min.x,
                    size.y - (unscale(it->y) - this->bb.min.y),
                    radius
                );
            }
        }
        
        fprintf(f,"\t</g>\n");
    }
    fprintf(f,"</svg>\n");
}

void
SVGExport::writeSVG(const std::string &outputfile)
{
    // align to origin taking raft into account
    BoundingBoxf3 bb = this->mesh.bounding_box();
    if (this->config.raft_layers > 0) {
        bb.min.x -= this->config.raft_offset.value;
        bb.min.y -= this->config.raft_offset.value;
        bb.max.x += this->config.raft_offset.value;
        bb.max.y += this->config.raft_offset.value;
    }
    this->mesh.translate(-bb.min.x, -bb.min.y, -bb.min.z);  // align to origin
    bb.translate(-bb.min.x, -bb.min.y, -bb.min.z);          // align to origin
    const Sizef3 size = bb.size();
    
    // if we are generating a raft, first_layer_height will not affect mesh slicing
    const float lh = this->config.layer_height.value;
    const float first_lh = this->config.first_layer_height.value;
    
    // generate the list of Z coordinates for mesh slicing
    // (we slice each layer at half of its thickness)
    std::vector<float> slice_z, layer_z;
    {
        const float first_slice_lh = (this->config.raft_layers > 0) ? lh : first_lh;
        slice_z.push_back(first_slice_lh/2);
        layer_z.push_back(first_slice_lh);
    }
    while (layer_z.back() + lh/2 <= this->mesh.stl.stats.max.z) {
        slice_z.push_back(layer_z.back() + lh/2);
        layer_z.push_back(layer_z.back() + lh);
    }
    
    // perform the slicing
    std::vector<ExPolygons> layers;
    TriangleMeshSlicer(&this->mesh).slice(slice_z, &layers);
    
    // generate a solid raft if requested
    if (this->config.raft_layers > 0) {
        ExPolygons raft = offset_ex(layers.front(), scale_(this->config.raft_offset));
        for (int i = this->config.raft_layers; i >= 1; --i) {
            layer_z.insert(layer_z.begin(), first_lh + lh * (i-1));
            layers.insert(layers.begin(), raft);
        }
        
        // prepend total raft height to all sliced layers
        for (int i = this->config.raft_layers; i < layer_z.size(); ++i)
            layer_z[i] += first_lh + lh * (this->config.raft_layers-1);
    }
    
    // generate support material
    std::vector<Points> support_material(layers.size());
    if (this->config.support_material) {
        // generate a grid of points according to the configured spacing,
        // covering the entire object bounding box
        Points support_material_points;
        for (coordf_t x = bb.min.x; x <= bb.max.x; x += this->config.support_material_spacing) {
            for (coordf_t y = bb.min.y; y <= bb.max.y; y += this->config.support_material_spacing) {
                support_material_points.push_back(Point(scale_(x), scale_(y)));
            }
        }
        
        // check overhangs, starting from the upper layer, and detect which points apply 
        // to each layer
        ExPolygons overhangs;
        for (int i = layer_z.size()-1; i >= 0; --i) {
            overhangs = diff_ex(union_(overhangs, layers[i+1]), layers[i]);
            for (Points::const_iterator it = support_material_points.begin(); it != support_material_points.end(); ++it) {
                for (ExPolygons::const_iterator e = overhangs.begin(); e != overhangs.end(); ++e) {
                    if (e->contains(*it)) {
                        support_material[i].push_back(*it);
                        break;
                    }
                }
            }
        }
    }
    
    double support_material_radius = this->config.support_material_extrusion_width.get_abs_value(this->config.layer_height)/2;
    
    FILE* f = fopen(outputfile.c_str(), "w");
    fprintf(f,
        "<?xml version=\"1.0\" encoding=\"UTF-8\" standalone=\"yes\"?>\n"
        "<!DOCTYPE svg PUBLIC \"-//W3C//DTD SVG 1.0//EN\" \"http://www.w3.org/TR/2001/REC-SVG-20010904/DTD/svg10.dtd\">\n"
        "<svg width=\"%f\" height=\"%f\" xmlns=\"http://www.w3.org/2000/svg\" xmlns:svg=\"http://www.w3.org/2000/svg\" xmlns:xlink=\"http://www.w3.org/1999/xlink\" xmlns:slic3r=\"http://slic3r.org/namespaces/slic3r\" viewport-fill=\"black\">\n"
        "<!-- Generated using Slic3r %s http://slic3r.org/ -->\n"
        , size.x, size.y, SLIC3R_VERSION);
    
    for (size_t i = 0; i < layer_z.size(); ++i) {
        fprintf(f, "\t<g id=\"layer%zu\" slic3r:z=\"%0.4f\">\n", i, layer_z[i]);
        for (ExPolygons::const_iterator it = layers[i].begin(); it != layers[i].end(); ++it) {
            std::string pd;
            Polygons pp = *it;
            for (Polygons::const_iterator mp = pp.begin(); mp != pp.end(); ++mp) {
                std::ostringstream d;
                d << "M ";
                for (Points::const_iterator p = mp->points.begin(); p != mp->points.end(); ++p) {
                    d << unscale(p->x) << " ";
                    d << unscale(p->y) << " ";
                }
                d << "z";
//.........这里部分代码省略.........