cocos2dX改变锚点位置

改变锚点时，同过计算偏移量修正position从而保持CCNode在屏幕上的位置不变

 

void CLayer::change_anchorpoint(CCNode* node,CCPoint newpt)
{
    float dx, dy, diffx, diffy, height, width;
    width = node->getContentSize().width;
    height = node->getContentSize().height;

    diffx = (newpt.x - node->getAnchorPoint().x)*width;
    diffy = (newpt.y - node->getAnchorPoint().y)*height;
    node->setPositionX(node->getPositionX() + diffx);
    node->setPositionY(node->getPositionY() + diffy);
    node->setAnchorPoint(newpt);
}

newpt为新锚点的位置