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剪辑边界示例

2024-5-18 18:38| 发布者: admin| 查看: 287| 评论: 0|原作者: admin|来自: AutoCAD

剪辑边界示例

在以下示例中，在绘制任何内容之前，剪辑边界被推送到剪辑边界堆栈上，并在此对象的绘制完成后再次弹出：

Adesk::Boolean
MyObject::subWorldDraw(AcGiWorldDraw* pDraw)
{
    AcGiWorldGeometry * pGeom = &pDraw->geometry();
    pGeom->pushModelTransform(myTransform());
    AcGiClipBoundary cb;
    cb.m_bDrawBoundary	= true;
    cb.m_vNormal = AcGeVector3d::kZAxis;
    cb.m_ptPoint = AcGePoint3d::kOrigin;
    // Two points treated as a rectangle, three creates a triangle
    cb.m_aptPoints.append(AcGePoint2d(0,0));
    cb.m_aptPoints.append(AcGePoint2d(5,5));
    // We are clipping in our own space
    cb.m_xToClipSpace.setToIdentity();
    cb.m_xInverseBlockRefXForm = myTransform().inverse();
    // No Z clipping
    cb.m_bClippingBack = cb.m_bClippingFront = false;
    cb.m_dFrontClipZ = cb.m_dBackClipZ = 0.;
    Adesk::Boolean bPopClipBoundary = pGeom->pushClipBoundary(&cb);
    // Draw something
    pGeom->circle(...);
    pGeom->popModelTransform();
    if(bPopClipBoundary){ pGeom->popClipBoundary(); }
    return true; // world-only
}

由于此裁剪是一项复杂的操作，因此某些 AcGi 实现可能不完全支持它。在这种情况下，AcGi 实现可能会从返回 false，并且不应调用。pushClipBoundary()popClipBoundary()