void QTriangulatingStroker::arcPoints(float cx, float cy, float fromX, float fromY, float toX, float toY, QVarLengthArray<float> &points)
{
float dx1 = fromX - cx;
float dy1 = fromY - cy;
float dx2 = toX - cx;
float dy2 = toY - cy;
// while more than 180 degrees left:
while (dx1 * dy2 - dx2 * dy1 < 0) {
float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
dx1 = tmpx;
dy1 = tmpy;
points.push_back(cx + dx1);
points.push_back(cy + dy1);
}
// while more than 90 degrees left:
while (dx1 * dx2 + dy1 * dy2 < 0) {
float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
dx1 = tmpx;
dy1 = tmpy;
points.push_back(cx + dx1);
points.push_back(cy + dy1);
}
// while more than 0 degrees left:
while (dx1 * dy2 - dx2 * dy1 > 0) {
float tmpx = dx1 * m_cos_theta - dy1 * m_sin_theta;
float tmpy = dx1 * m_sin_theta + dy1 * m_cos_theta;
dx1 = tmpx;
dy1 = tmpy;
points.push_back(cx + dx1);
points.push_back(cy + dy1);
}
// remove last point which was rotated beyond [toX, toY].
if (!points.empty())
points.resize(points.size() - 2);
}
