Method findClosestSegment

src/Core/Transform/Polygon.cpp:150–201

    }

    PolygonSegment Polygon::findClosestSegment(const Transform::UnitVector& position)
    {
        const Transform::UnitVector p3 = position.to<Transform::Units::SceneUnits>();
        const auto distanceLineFromPoint = [](const Transform::UnitVector& point,
                                               const Transform::UnitVector& lineP1,
                                               const Transform::UnitVector& lineP2) {
            Transform::UnitVector lineDiff = lineP2 - lineP1;
            if (lineDiff.x == 0 && lineDiff.y == 0)
            {
                lineDiff = point - lineP1;
                return sqrt(lineDiff.x * lineDiff.x + lineDiff.y * lineDiff.y);
            }

            const double t
                = ((point.x - lineP1.x) * lineDiff.x + (point.y - lineP1.y) * lineDiff.y)
                / (lineDiff.x * lineDiff.x + lineDiff.y * lineDiff.y);

            if (t < 0)
            {
                // point is nearest to the first point i.e x1 and y1
                lineDiff = point - lineP1;
            }
            else if (t > 1)
            {
                // point is nearest to the end point i.e x2 and y2
                lineDiff = point - lineP2;
            }
            else
            {
                // if perpendicular line intersect the line segment.
                lineDiff.x = point.x - (lineP1.x + t * lineDiff.x);
                lineDiff.y = point.y - (lineP1.y + t * lineDiff.y);
            }

            // returning shortest distance
            return sqrt(lineDiff.x * lineDiff.x + lineDiff.y * lineDiff.y);
        };
        double shortestDistance = -1;
        std::size_t shortestIndex = 0;
        for (std::size_t i = 0, j = getAllPoints().size() - 1; i < getAllPoints().size();
             j = i++)
        {
            const double currentDistance
                = distanceLineFromPoint(p3, this->get(i), this->get(j));
            if (shortestDistance == -1 || currentDistance < shortestDistance)
            {
                shortestDistance = currentDistance;
                shortestIndex = i;
            }
        }
        return this->getSegment(shortestIndex);
    }

    std::optional<PolygonSegment> Polygon::getSegmentContainingPoint(
        const Transform::UnitVector& position, const double tolerance)