getLetter与getPosition的疑惑

Studio
#1

win7 32位，cocos2dxV3.10

auto label1 = Label::createWithTTF(“淡定淡定淡定”, config::defaultFont, 80);
label1->setTextColor(Color4B::BLACK);
label1->setPosition(Vec2(origin.x + visibleSize.width / 2 , origin.y + visibleSize.height - label1->getContentSize().height));
this->addChild(label1 , 1);
Vec2 pos0 = label1->getPosition();
auto w = label1->getLetter(0);
Vec2 pos1 = w->getPosition();

LayerColor* lc = LayerColor::create(Color4B::BLUE);//显示pos1的位置与大小
lc->setPosition(pos1);
lc->setContentSize(w->getContentSize());
lc->setOpacity(128);
this->addChild(lc);

为什么pos0与pos1不相等，还相差那么远？？
第一个字“淡”的位置应该是pos0才对啊