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#include "merge_lines.hpp"
#include <sstream>
namespace mbgl {
namespace util {
unsigned int mergeFromRight(std::vector<SymbolFeature> &features,
std::map<std::string, unsigned int> &rightIndex,
std::map<std::string, unsigned int>::iterator left,
std::string &rightKey,
std::vector<std::vector<Coordinate>> &geom) {
unsigned int index = left->second;
rightIndex.erase(left);
rightIndex[rightKey] = index;
features[index].geometry[0].pop_back();
features[index].geometry[0].insert(
features[index].geometry[0].end(), geom[0].begin(), geom[0].end());
geom[0].clear();
return index;
}
unsigned int mergeFromLeft(std::vector<SymbolFeature> &features,
std::map<std::string, unsigned int> &leftIndex,
std::string &leftKey,
std::map<std::string, unsigned int>::iterator right,
std::vector<std::vector<Coordinate>> &geom) {
unsigned int index = right->second;
leftIndex.erase(right);
leftIndex[leftKey] = index;
geom[0].pop_back();
geom[0].insert(
geom[0].end(), features[index].geometry[0].begin(), features[index].geometry[0].end());
features[index].geometry[0].clear();
std::swap(features[index].geometry[0], geom[0]);
return index;
}
std::string
getKey(const std::u32string &text, const std::vector<std::vector<Coordinate>> &geom, bool onRight) {
const Coordinate &coord = onRight ? geom[0].back() : geom[0].front();
std::ostringstream key;
for (const char32_t &c : text) {
key << (char)c;
}
key << ":" << coord.x << ":" << coord.y;
return key.str();
}
void mergeLines(std::vector<SymbolFeature> &features) {
std::map<std::string, unsigned int> leftIndex;
std::map<std::string, unsigned int> rightIndex;
for (unsigned int k = 0; k < features.size(); k++) {
SymbolFeature &feature = features[k];
std::vector<std::vector<Coordinate>> &geometry = feature.geometry;
if (!feature.label.length()) {
continue;
}
std::string leftKey = getKey(feature.label, geometry, false);
std::string rightKey = getKey(feature.label, geometry, true);
auto left = rightIndex.find(leftKey);
auto right = leftIndex.find(rightKey);
if ((left != rightIndex.end()) && (right != leftIndex.end()) &&
(left->second != right->second)) {
// found lines with the same text adjacent to both ends of the current line, merge all
// three
unsigned int j = mergeFromLeft(features, leftIndex, leftKey, right, geometry);
unsigned int i =
mergeFromRight(features, rightIndex, left, rightKey, features[j].geometry);
leftIndex.erase(leftKey);
rightIndex.erase(rightKey);
rightIndex[getKey(feature.label, features[i].geometry, true)] = i;
} else if (left != rightIndex.end()) {
// found mergeable line adjacent to the start of the current line, merge
mergeFromRight(features, rightIndex, left, rightKey, geometry);
} else if (right != leftIndex.end()) {
// found mergeable line adjacent to the end of the current line, merge
mergeFromLeft(features, leftIndex, leftKey, right, geometry);
} else {
// no adjacent lines, add as a new item
leftIndex[leftKey] = k;
rightIndex[rightKey] = k;
}
}
}
} // end namespace util
} // end namespace mbgl
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