C++ Polylines::emplace_back方法代码示例

static Polylines make_gyroid_waves(double gridZ, double density_adjusted, double line_spacing, double width, double height)
{
    const double scaleFactor = scale_(line_spacing) / density_adjusted;
 //scale factor for 5% : 8 712 388
 // 1z = 10^-6 mm ?
    const double z     = gridZ / scaleFactor;
    const double z_sin = sin(z);
    const double z_cos = cos(z);

    bool vertical = (std::abs(z_sin) <= std::abs(z_cos));
    double lower_bound = 0.;
    double upper_bound = height;
    bool flip = true;
    if (vertical) {
        flip = false;
        lower_bound = -M_PI;
        upper_bound = width - M_PI_2;
        std::swap(width,height);
    }

    std::vector<Vec2d> one_period = make_one_period(width, scaleFactor, z_cos, z_sin, vertical, flip); // creates one period of the waves, so it doesn't have to be recalculated all the time
    Polylines result;

    for (double y0 = lower_bound; y0 < upper_bound+EPSILON; y0 += 2*M_PI)           // creates odd polylines
            result.emplace_back(make_wave(one_period, width, height, y0, scaleFactor, z_cos, z_sin, vertical));

    flip = !flip;                                                                   // even polylines are a bit shifted
    one_period = make_one_period(width, scaleFactor, z_cos, z_sin, vertical, flip); // updates the one period sample
    for (double y0 = lower_bound + M_PI; y0 < upper_bound+EPSILON; y0 += 2*M_PI)    // creates even polylines
            result.emplace_back(make_wave(one_period, width, height, y0, scaleFactor, z_cos, z_sin, vertical));

    return result;
}

static Polylines make_gyroid_waves(double gridZ, double density, double layer_width, double width, double height)
{
    double scaleFactor = scale_(layer_width) / density;
    double segmentSize = 0.5 * density;
 //scale factor for 5% : 8 712 388
 // 1z = 10^-6 mm ?
    double z     = gridZ / scaleFactor;
    double z_sin = sin(z);
    double z_cos = cos(z);
    Polylines result;
    if (abs(z_sin) <= abs(z_cos)) {
        // Vertical wave
        double x0 = M_PI * (int)((- 0.5 * M_PI) / M_PI - 1.);
        bool   flip          = ((int)(x0 / M_PI + 1.) & 1) != 0;
        for (; x0 < width - 0.5 * M_PI; x0 += M_PI, flip = ! flip)
            result.emplace_back(make_wave_vertical(width, height, x0, segmentSize, scaleFactor, z_cos, z_sin, flip));
    } else {
        // Horizontal wave
        bool flip = true;
        for (double y0 = 0.; y0 < width; y0 += M_PI, flip = !flip)
            result.emplace_back(make_wave_horizontal(width, height, y0, segmentSize, scaleFactor, z_cos, z_sin, flip));
    }
    return result;
}

Polylines _clipper_pl(ClipperLib::ClipType clipType, const Polygons &subject, const Polygons &clip, bool safety_offset_)
{
    // transform input polygons into polylines
    Polylines polylines;
    polylines.reserve(subject.size());
    for (Polygons::const_iterator polygon = subject.begin(); polygon != subject.end(); ++polygon)
        polylines.emplace_back(polygon->operator Polyline());  // implicit call to split_at_first_point()
    
    // perform clipping
    Polylines retval = _clipper_pl(clipType, polylines, clip, safety_offset_);
    
    /* If the split_at_first_point() call above happens to split the polygon inside the clipping area
       we would get two consecutive polylines instead of a single one, so we go through them in order
       to recombine continuous polylines. */
    for (size_t i = 0; i < retval.size(); ++i) {
        for (size_t j = i+1; j < retval.size(); ++j) {
            if (retval[i].points.back() == retval[j].points.front()) {
                /* If last point of i coincides with first point of j,
                   append points of j to i and delete j */
                retval[i].points.insert(retval[i].points.end(), retval[j].points.begin()+1, retval[j].points.end());
                retval.erase(retval.begin() + j);
                --j;
            } else if (retval[i].points.front() == retval[j].points.back()) {
                /* If first point of i coincides with last point of j,
                   prepend points of j to i and delete j */
                retval[i].points.insert(retval[i].points.begin(), retval[j].points.begin(), retval[j].points.end()-1);
                retval.erase(retval.begin() + j);
                --j;
            } else if (retval[i].points.front() == retval[j].points.front()) {
                /* Since Clipper does not preserve orientation of polylines, 
                   also check the case when first point of i coincides with first point of j. */
                retval[j].reverse();
                retval[i].points.insert(retval[i].points.begin(), retval[j].points.begin(), retval[j].points.end()-1);
                retval.erase(retval.begin() + j);
                --j;
            } else if (retval[i].points.back() == retval[j].points.back()) {
                /* Since Clipper does not preserve orientation of polylines, 
                   also check the case when last point of i coincides with last point of j. */
                retval[j].reverse();
                retval[i].points.insert(retval[i].points.end(), retval[j].points.begin()+1, retval[j].points.end());
                retval.erase(retval.begin() + j);
                --j;
            }
        }
    }
    return retval;
}

Lines
_clipper_ln(ClipperLib::ClipType clipType, const Lines &subject, const Polygons &clip,
    bool safety_offset_)
{
    // convert Lines to Polylines
    Polylines polylines;
    polylines.reserve(subject.size());
    for (const Line &line : subject)
        polylines.emplace_back(Polyline(line.a, line.b));
    
    // perform operation
    polylines = _clipper_pl(clipType, polylines, clip, safety_offset_);
    
    // convert Polylines to Lines
    Lines retval;
    for (Polylines::const_iterator polyline = polylines.begin(); polyline != polylines.end(); ++polyline)
        retval.emplace_back(polyline->operator Line());
    return retval;
}

void FillGyroid::_fill_surface_single(
    const FillParams                &params, 
    unsigned int                     thickness_layers,
    const std::pair<float, Point>   &direction, 
    ExPolygon                       &expolygon, 
    Polylines                       &polylines_out)
{
    // no rotation is supported for this infill pattern
    BoundingBox bb = expolygon.contour.bounding_box();
    coord_t     distance = coord_t(scale_(this->spacing) / (params.density*this->scaling));

    // align bounding box to a multiple of our grid module
    bb.merge(_align_to_grid(bb.min, Point(2*M_PI*distance, 2*M_PI*distance)));
    
    // generate pattern
    Polylines   polylines = make_gyroid_waves(
        scale_(this->z),
        params.density*this->scaling,
        this->spacing,
        ceil(bb.size().x / distance) + 1.,
        ceil(bb.size().y / distance) + 1.);
    
    // move pattern in place
    for (Polyline &polyline : polylines)
        polyline.translate(bb.min.x, bb.min.y);

    // clip pattern to boundaries
    polylines = intersection_pl(polylines, (Polygons)expolygon);

    // connect lines
    if (! params.dont_connect && ! polylines.empty()) { // prevent calling leftmost_point() on empty collections
        ExPolygon expolygon_off;
        {
            ExPolygons expolygons_off = offset_ex(expolygon, (float)SCALED_EPSILON);
            if (! expolygons_off.empty()) {
                // When expanding a polygon, the number of islands could only shrink. Therefore the offset_ex shall generate exactly one expanded island for one input island.
                assert(expolygons_off.size() == 1);
                std::swap(expolygon_off, expolygons_off.front());
            }
        }
        Polylines chained = PolylineCollection::chained_path_from(
            std::move(polylines), 
            PolylineCollection::leftmost_point(polylines), false); // reverse allowed
        bool first = true;
        for (Polyline &polyline : chained) {
            if (! first) {
                // Try to connect the lines.
                Points &pts_end = polylines_out.back().points;
                const Point &first_point = polyline.points.front();
                const Point &last_point = pts_end.back();
                // TODO: we should also check that both points are on a fill_boundary to avoid 
                // connecting paths on the boundaries of internal regions
                // TODO: avoid crossing current infill path
                if (first_point.distance_to(last_point) <= 5 * distance && 
                    expolygon_off.contains(Line(last_point, first_point))) {
                    // Append the polyline.
                    pts_end.insert(pts_end.end(), polyline.points.begin(), polyline.points.end());
                    continue;
                }
            }
            // The lines cannot be connected.
            polylines_out.emplace_back(std::move(polyline));
            first = false;
        }
    }
}