C++ GeometryCoordinates::empty方法代码示例

GeometryCollection VectorTileFeature::getGeometries() const {
    uint8_t cmd = 1;
    uint32_t length = 0;
    int32_t x = 0;
    int32_t y = 0;
    const float scale = float(util::EXTENT) / layer.extent;

    GeometryCollection lines;

    lines.emplace_back();
    GeometryCoordinates* line = &lines.back();

    auto g_itr = geometry_iter.begin();
    while (g_itr != geometry_iter.end()) {
        if (length == 0) {
            uint32_t cmd_length = static_cast<uint32_t>(*g_itr++);
            cmd = cmd_length & 0x7;
            length = cmd_length >> 3;
        }

        --length;

        if (cmd == 1 || cmd == 2) {
            x += protozero::decode_zigzag32(static_cast<uint32_t>(*g_itr++));
            y += protozero::decode_zigzag32(static_cast<uint32_t>(*g_itr++));

            if (cmd == 1 && !line->empty()) { // moveTo
                lines.emplace_back();
                line = &lines.back();
            }

            line->emplace_back(::round(x * scale), ::round(y * scale));

        } else if (cmd == 7) { // closePolygon
            if (!line->empty()) {
                line->push_back((*line)[0]);
            }

        } else {
            throw std::runtime_error("unknown command");
        }
    }

GeometryCollection VectorTileFeature::getGeometries() const {
    pbf data(geometry_pbf);
    uint8_t cmd = 1;
    uint32_t length = 0;
    int32_t x = 0;
    int32_t y = 0;

    GeometryCollection lines;

    lines.emplace_back();
    GeometryCoordinates* line = &lines.back();

    while (data.data < data.end) {
        if (length == 0) {
            uint32_t cmd_length = data.varint();
            cmd = cmd_length & 0x7;
            length = cmd_length >> 3;
        }

        --length;

        if (cmd == 1 || cmd == 2) {
            x += data.svarint();
            y += data.svarint();

            if (cmd == 1 && !line->empty()) { // moveTo
                lines.emplace_back();
                line = &lines.back();
            }

            line->emplace_back(x, y);

        } else if (cmd == 7) { // closePolygon
            if (!line->empty()) {
                line->push_back((*line)[0]);
            }

        } else {
            throw std::runtime_error("unknown command");
        }
    }

static GeometryCoordinates fromClipperPath(const ClipperLib::Path& path) {
    GeometryCoordinates result;
    result.reserve(path.size() + 1);
    
    result.reserve(path.size());
    for (const auto& p : path) {
        using Coordinate = GeometryCoordinates::coordinate_type;
        assert(p.x >= std::numeric_limits<Coordinate>::min());
        assert(p.x <= std::numeric_limits<Coordinate>::max());
        assert(p.y >= std::numeric_limits<Coordinate>::min());
        assert(p.y <= std::numeric_limits<Coordinate>::max());
        result.emplace_back(Coordinate(p.x), Coordinate(p.y));
    }
    
    // Clipper does not repeat initial point, but our geometry model requires it.
    if (!result.empty()) {
        result.push_back(result.front());
    }
    
    return result;
}

Anchors getAnchors(const GeometryCoordinates &line, float spacing,
        const float maxAngle, const float textLeft, const float textRight,
        const float iconLeft, const float iconRight,
        const float glyphSize, const float boxScale, const float overscaling) {
    if (line.empty()) return {};

    // Resample a line to get anchor points for labels and check that each
    // potential label passes text-max-angle check and has enough froom to fit
    // on the line.

    const float angleWindowSize = (textLeft - textRight) != 0.0f ?
        3.0f / 5.0f * glyphSize * boxScale :
        0;

    const float labelLength = fmax(textRight - textLeft, iconRight - iconLeft);

    // Is the line continued from outside the tile boundary?
    const bool continuedLine = (line[0].x == 0 || line[0].x == util::EXTENT || line[0].y == 0 || line[0].y == util::EXTENT);

    // Is the label long, relative to the spacing?
    // If so, adjust the spacing so there is always a minimum space of `spacing / 4` between label edges.
    if (spacing - labelLength * boxScale  < spacing / 4) {
        spacing = labelLength * boxScale + spacing / 4;
    }

    // Offset the first anchor by:
    // Either half the label length plus a fixed extra offset if the line is not continued
    // Or half the spacing if the line is continued.

    // For non-continued lines, add a bit of fixed extra offset to avoid collisions at T intersections.
    const float fixedExtraOffset = glyphSize * 2;

    const float offset = !continuedLine ?
    std::fmod((labelLength / 2 + fixedExtraOffset) * boxScale * overscaling, spacing) :
    std::fmod(spacing / 2 * overscaling, spacing);

    return resample(line, offset, spacing, angleWindowSize, maxAngle, labelLength * boxScale, continuedLine, false);
}