private void RenderNodeRecursively(Node n, RenderContext rc, RenderDevice rs)
{
if (n == null)
{
return;
}
if (!n.Visible) // 'Visible == false' would hide all children
{
return;
}
// 两个说明：
// 1) m_localPosDocked 并非一个累积量，因此不需在使用完之后重置
// 2) m_localPosScrolled 并非一个累积量，因此不需在使用完之后重置
// 3) m_accumTranslate 只需计算一次，结果可供整个 Children 列表共享使用
//
// 上面这三点决定了 m_localPosDocked 和 m_localPosScrolled 作用于当前节点
// 而 m_accumTranslate 作用于当前节点的 Children 列表
Point localPosDocked = n.GetDockedPos();
rc.m_localPosDocked = localPosDocked;
Point localScrolled = Point.Empty - (Size)n.CurrentScrollOffset;
rc.m_localPosScrolled = localScrolled;
rs.RenderNode(n, rc);
rc.m_accumTranslate.X += (localPosDocked.X + localScrolled.X);
rc.m_accumTranslate.Y += (localPosDocked.Y + localScrolled.Y);
Rectangle oldClip = rs.GetCurrentClip(rc);
if (n.IsScrollable())
{
rs.SetCurrentClip(rc, n.GetWorldBounds());
}
n.TraverseChildren((Node child) => { RenderNodeRecursively(child, rc, rs); });
if (n.IsScrollable())
{
rs.SetCurrentClip(rc, oldClip);
}
rc.m_accumTranslate.X -= (localPosDocked.X + localScrolled.X);
rc.m_accumTranslate.Y -= (localPosDocked.Y + localScrolled.Y);
}