Function edgeColoringByDistance

MyGUIEngine/src/msdfgen/core/edge-coloring.cpp:395–529

}

void edgeColoringByDistance(Shape &shape, double angleThreshold, unsigned long long seed) {

    std::vector<EdgeSegment *> edgeSegments;
    std::vector<int> splineStarts;

    double crossThreshold = sin(angleThreshold);
    std::vector<int> corners;
    for (std::vector<Contour>::iterator contour = shape.contours.begin(); contour != shape.contours.end(); ++contour)
        if (!contour->edges.empty()) {
            // Identify corners
            corners.clear();
            Vector2 prevDirection = contour->edges.back()->direction(1);
            int index = 0;
            for (std::vector<EdgeHolder>::const_iterator edge = contour->edges.begin(); edge != contour->edges.end(); ++edge, ++index) {
                if (isCorner(prevDirection.normalize(), (*edge)->direction(0).normalize(), crossThreshold))
                    corners.push_back(index);
                prevDirection = (*edge)->direction(1);
            }

            splineStarts.push_back((int) edgeSegments.size());
            // Smooth contour
            if (corners.empty())
                for (std::vector<EdgeHolder>::iterator edge = contour->edges.begin(); edge != contour->edges.end(); ++edge)
                    edgeSegments.push_back(&**edge);
            // "Teardrop" case
            else if (corners.size() == 1) {
                int corner = corners[0];
                if (contour->edges.size() >= 3) {
                    int m = (int) contour->edges.size();
                    for (int i = 0; i < m; ++i) {
                        if (i == m/2)
                            splineStarts.push_back((int) edgeSegments.size());
                        if (symmetricalTrichotomy(i, m))
                            edgeSegments.push_back(&*contour->edges[(corner+i)%m]);
                        else
                            contour->edges[(corner+i)%m]->color = WHITE;
                    }
                } else if (contour->edges.size() >= 1) {
                    // Less than three edge segments for three colors => edges must be split
                    EdgeSegment *parts[7] = { };
                    contour->edges[0]->splitInThirds(parts[0+3*corner], parts[1+3*corner], parts[2+3*corner]);
                    if (contour->edges.size() >= 2) {
                        contour->edges[1]->splitInThirds(parts[3-3*corner], parts[4-3*corner], parts[5-3*corner]);
                        edgeSegments.push_back(parts[0]);
                        edgeSegments.push_back(parts[1]);
                        parts[2]->color = parts[3]->color = WHITE;
                        splineStarts.push_back((int) edgeSegments.size());
                        edgeSegments.push_back(parts[4]);
                        edgeSegments.push_back(parts[5]);
                    } else {
                        edgeSegments.push_back(parts[0]);
                        parts[1]->color = WHITE;
                        splineStarts.push_back((int) edgeSegments.size());
                        edgeSegments.push_back(parts[2]);
                    }
                    contour->edges.clear();
                    for (int i = 0; parts[i]; ++i)
                        contour->edges.push_back(EdgeHolder(parts[i]));