cocos2d-x 文本框

1.所有文本框必须实现CCLabelProtocol接口

2.CCLableTTF比另外两个文本框渲染慢

3.CCLabelBMFont中每个文字相当于一个CCSprite，可以旋转，移动，改变尺寸等

下面列出基本的用法:(很多其他的用法请查阅官方的API文档)

    // add a label shows "Hello World"
    // create and initialize a label
    CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", TITLE_FONT_SIZE);   
    // position the label on the center of the screen
    pLabel->setPosition(ccp(origin.x + visibleSize.width/2,
                            origin.y + visibleSize.height - pLabel->getContentSize().height));

    // add the label as a child to this layer
    this->addChild(pLabel, 1);

CCLabelBMFont* label = CCLabelBMFont::create("configuration", "fonts/bitmapFontTest3.fnt");

CCLabelAtlas* labelAtlas = CCLabelAtlas::create("0123456789", "fonts/labelatlas.png", 16, 24, '.');