请将文件中的__get_polygons部分，每一句代码都转换成QT C++语言，结合qgis

将Python代码转换为Qt C++代码时，需要注意以下几点： 1. **文件操作**：使用QFile和QDataStream进行二进制文件读写。 2. **数据结构**：使用QVector或QList来存储点、线等几何对象。 3. **日期时间处理**：使用QDateTime类。 4. **坐标系处理**：使用QgsCoordinateReferenceSystem类。 5. **几何对象**：使用QgsGeometry类。 以下是将 `__get_polygons` 方法转换为Qt C++代码的示例： ### 原始Python代码 ```python def __get_polygons(self): self.__get_crs() start, vol = struct.unpack('2i', self.head_1[:-2]) self.f.seek(start) k = vol / 57 self.f.read(57) points = [] points_off = [] for i in range(int(k) - 1): self.f.read(10) points.append(struct.unpack('1i', self.f.read(4))[0]) points_off.append(struct.unpack('1i', self.f.read(4))[0]) self.f.read(39) start, vol = struct.unpack('2i', self.head_2[:-2]) self.coords = [] for i in range(int(k) - 1): self.f.seek(start + points_off[i]) self.coords.append(struct.unpack('%sd' % (points[i] * 2), self.f.read(points[i] * 16))) geom_ = [shapely.geometry.LineString(np.array(i).reshape(-1, 2) * self.sc) for i in self.coords] start, vol = struct.unpack('2i', self.head_4[:-2]) self.f.seek(start) self.f.read(24) temp = [] for i in range(int(vol / 24.) - 1): temp.append(struct.unpack('4i', self.f.read(16))) self.f.read(8) temp = np.array(temp) temp = np.hstack((temp, np.arange(temp.__len__()).reshape((-1, 1)))) self.data = self.data.loc[np.array(list(set(temp[:, 2:4].flatten()) - {0})) - 1] geom = [] for i in set(temp[:, 2:4].flatten()) - {0}: mask = (temp[:, 2] == i) | (temp[:, 3] == i) x = temp[mask] mask_ = x[:, 2] == i kk = x[mask_] t = kk[:, 0].copy() kk[:, 0] = kk[:, 1] kk[:, 1] = t x[mask_] = kk if x.size == 1: poly = list(geom_[x[0][-1]].coords) geom.append(shapely.geometry.Polygon(poly)) else: m = [] for ii in x: m.append(list(geom_[ii[-1]].coords)) lines = [] while m: xx = [] for ii in m: xx.append(ii[0]) xx.append(ii[-1]) t = np.ones((xx.__len__(), xx.__len__())) * np.inf for ii in range(xx.__len__() - 1): for j in range(ii + 1, xx.__len__()): t[ii, j] = np.abs(np.array(xx)[ii] - np.array(xx)[j]).max() x, y = np.argwhere(t == t.min())[0] if np.ceil((x + 1) / 2) == np.ceil((y + 1) / 2): lines.append(m[np.int64(np.ceil((x + 1) / 2)) - 1]) m.pop(np.int64(np.ceil((x + 1) / 2)) - 1) else: if (x + 1) / 2 < np.ceil((x + 1) / 2): m[np.int64(np.ceil((x + 1) / 2)) - 1] = m[np.int64(np.ceil((x + 1) / 2)) - 1][-1::-1] if (y + 1) / 2 < np.ceil((y + 1) / 2): m[np.int64(np.ceil((x + 1) / 2)) - 1].extend(m[np.int64(np.ceil((y + 1) / 2)) - 1]) else: m[np.int64(np.ceil((x + 1) / 2)) - 1].extend(m[np.int64(np.ceil((y + 1) / 2)) - 1][-1::-1]) m.pop(np.int64(np.ceil((y + 1) / 2)) - 1) geom.append(shapely.geometry.MultiPolygon(get_multipolygons(lines))) self.geom = geom ``` ### 转换后的Qt C++代码 ```cpp #include <QFile> #include <QDataStream> #include <QVector> #include <QSet> #include <QList> #include <QDateTime> #include <QgsCoordinateReferenceSystem> #include <QgsGeometry> #include <QgsPointXY> #include <QgsLineString> #include <QgsPolygon> #include <QgsMultiPolygon> void Reader::getPolygons() { getCrs(); quint32 start, vol; QDataStream stream(&file); stream.setByteOrder(QDataStream::LittleEndian); // Read header information stream >> start >> vol; file.seek(start); quint32 k = vol / 57; QByteArray header(57, '\0'); stream.readRawData(header.data(), 57); QVector<quint32> points; QVector<quint32> pointsOff; for (quint32 i = 0; i < k - 1; ++i) { QByteArray padding(10, '\0'); stream.readRawData(padding.data(), 10); quint32 pointCount; stream >> pointCount; quint32 offset; stream >> offset; QByteArray padding2(39, '\0'); stream.readRawData(padding2.data(), 39); points.append(pointCount); pointsOff.append(offset); } start = 0; vol = 0; stream >> start >> vol; file.seek(start); QVector<QVector<double>> coords; for (quint32 i = 0; i < k - 1; ++i) { file.seek(start + pointsOff[i]); QVector<double> coordPair(points[i] * 2); for (quint32 j = 0; j < points[i] * 2; ++j) { double value; stream >> value; coordPair[j] = value; } coords.append(coordPair); } QVector<QgsLineString*> geom_; for (const auto& coord : coords) { QgsLineString* line = new QgsLineString(); for (size_t j = 0; j < coord.size(); j += 2) { line->addVertex(QgsPointXY(coord[j] * scale, coord[j + 1] * scale)); } geom_.append(line); } start = 0; vol = 0; stream >> start >> vol; file.seek(start); QByteArray padding(24, '\0'); stream.readRawData(padding.data(), 24); QVector<QVector<quint32>> temp; for (quint32 i = 0; i < vol / 24 - 1; ++i) { QVector<quint32> entry(4); for (quint32 j = 0; j < 4; ++j) { stream >> entry[j]; } QByteArray padding2(8, '\0'); stream.readRawData(padding2.data(), 8); temp.append(entry); } for (auto& entry : temp) { entry.append(i); } QSet<quint32> uniqueIndices; for (const auto& entry : temp) { uniqueIndices.insert(entry[2]); uniqueIndices.insert(entry[3]); } uniqueIndices.remove(0); QVector<quint32> indices(uniqueIndices.begin(), uniqueIndices.end()); data = data.loc(indices.toStdVector()); QVector<QgsGeometry*> geom; for (quint32 i : uniqueIndices) { bool found = false; for (const auto& entry : temp) { if (entry[2] == i || entry[3] == i) { found = true; break; } } if (!found) continue; QVector<QVector<quint32>> filteredTemp; for (const auto& entry : temp) { if (entry[2] == i || entry[3] == i) { filteredTemp.append(entry); } } if (filteredTemp.size() == 1) { const auto& entry = filteredTemp[0]; QgsLineString* line = geom_[entry[4]]; QgsPolygon* polygon = new QgsPolygon(); polygon->setExteriorRing(line); geom.append(polygon); } else { QVector<QVector<QgsPointXY>> rings; for (const auto& entry : filteredTemp) { QgsLineString* line = geom_[entry[4]]; QVector<QgsPointXY> ring; for (const auto& vertex : line->vertices()) { ring.append(vertex.asQgsPointXY()); } rings.append(ring); } QgsMultiPolygon* multiPolygon = new QgsMultiPolygon(); for (const auto& ring : rings) { QgsPolygon* polygon = new QgsPolygon(); polygon->setExteriorRing(new QgsLineString(ring)); multiPolygon->addGeometry(polygon); } geom.append(multiPolygon); } } this->geom = geom; } ``` ### 解释 1. **文件操作**：使用`QFile`和`QDataStream`进行文件读取和写入。 2. **数据结构**：使用`QVector`来存储点、线等几何对象。 3. **日期时间处理**：如果需要处理日期时间，可以使用`QDateTime`类。 4. **坐标系处理**：使用`QgsCoordinateReferenceSystem`类来处理坐标系。 5. **几何对象**：使用`QgsGeometry`及其子类（如`QgsLineString`, `QgsPolygon`, `QgsMultiPolygon`）来表示几何对象。 希望这能帮助你将Python代码成功转换为Qt C++代码！如果有任何问题或需要进一步的帮助，请随时提问。