Method curveToPolygon

src/frameworks/UBGeometryUtils.cpp:247–265

* @brief Build and return a polygon from a list of points (at least 2), and start and end widths. * * The resulting polygon will pass by all points in the curve; its thickness is calculated at each point * of the curve (linearly interpolated between start and end widths) and the segments are joined by * (approximately) curved joints. * * Like with lineToPolygon, the ends are semi-circular.

 * Like with lineToPolygon, the ends are semi-circular.
 */
QPolygonF UBGeometryUtils::curveToPolygon(const QList<QPointF>& points, qreal startWidth, qreal endWidth)
{
    int n_points = points.size();

    if (n_points < 2)
        return QPolygonF();

    if (n_points == 2)
        return lineToPolygon(points[0], points[1], startWidth, endWidth);

    QList<QPair<QPointF, qreal> > pointsAndWidths;
    for (int i(0); i < n_points; ++i) {
        qreal width = startWidth + (qreal(i)/qreal(n_points-1)) * (endWidth - startWidth);

        pointsAndWidths << QPair<QPointF, qreal>(points[i], width);
    }

    return curveToPolygon(pointsAndWidths, true, true);
}

/**
 * @brief Build and return a polygon from a list of points and thicknesses (at least 2)