m_ry4
double m_ry4;
m_arc.init(m_x1 + m_rx4, m_y2 - m_ry4, m_rx4, m_ry4,
m_rx1 = m_ry1 = m_rx2 = m_ry2 = m_rx3 = m_ry3 = m_rx4 = m_ry4 = r;
m_ry1 = m_ry2 = m_ry3 = m_ry4 = ry;
m_ry3 = m_ry4 = ry_top;
m_rx3 = rx3; m_ry3 = ry3; m_rx4 = rx4; m_ry4 = ry4;
t = dy / (m_ry3 + m_ry4); if(t < k) k = t;
m_rx3 *= k; m_ry3 *= k; m_rx4 *= k; m_ry4 *= k;