cocos2d-x中的尺寸之一

cocos2d-x中的尺寸函数繁多，官方文档对各种尺寸没有很好的描述，网上文章更加寥寥，对尺寸和位置的理解如果不到位，写代码就非常困难，需要猜测尝试，效率低下。这个文章我将研究一些我所迷惑的尺寸函数，记录在此。

先看如下代码：

bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director
    CCDirector* pDirector = CCDirector::sharedDirector();
    CCEGLView* pEGLView = CCEGLView::sharedOpenGLView();
	pDirector->setOpenGLView(pEGLView);

	pDirector->getWinSize();
	pDirector->getWinSizeInPixels();
	pDirector->getVisibleSize();

	pEGLView->getFrameSize();
	pEGLView->getDesignResolutionSize();
	pEGLView->getVisibleSize();

在applicationDidFinishLaunching中，我们上面函数调用分别是什么意思呢，粗略的说是窗口大小呗，通过CCLOG我们把调试信息打印出来，代码变成如下：

CCSize size;
	size = pDirector->getWinSize();
	CCLOG("width = %f height = %f, pDirector->getWinSize", size.width, size.height);
	size = pDirector->getWinSizeInPixels();
	CCLOG("width = %f height = %f, pDirector->getWinSizeInPixels", size.width, size.height);
	size = pDirector->getVisibleSize();
	CCLOG("width = %f height = %f, pDirector->getVisibleSize", size.width, size.height);

	size = pEGLView->getFrameSize();
	CCLOG("width = %f height = %f, pEGLView->getFrameSize", size.width, size.height);
	size = pEGLView->getDesignResolutionSize();
	CCLOG("width = %f height = %f, pEGLView->getDesignResolutionSize", size.width, size.height);
	size = pEGLView->getVisibleSize();
	CCLOG("width = %f height = %f, pEGLView->getVisibleSize", size.width, size.height);

打印出来调试信息如下：

从调试信息看，默认的程序，这些尺寸都是一样的，是有点头疼吧，都是一样的，你搞那么多尺寸干嘛呢.......

为了让这些值不一样，我们试着加一些代码。加一行代码如下：

bool AppDelegate::applicationDidFinishLaunching() {
    // initialize director
    CCDirector* pDirector = CCDirector::sharedDirector();
    CCEGLView* pEGLView = CCEGLView::sharedOpenGLView();
	pDirector->setOpenGLView(pEGLView);

	pDirector->setContentScaleFactor(2.0f);

	CCSize size;
	size = pDirector->getWinSize();
	CCLOG("width = %f height = %f, pDirector->getWinSize", size.width, size.height);
	size = pDirector->getWinSizeInPixels();
	CCLOG("width = %f height = %f, pDirector->getWinSizeInPixels", size.width, size.height);
	size = pDirector->getVisibleSize();
	CCLOG("width = %f height = %f, pDirector->getVisibleSize", size.width, size.height);

	size = pEGLView->getFrameSize();
	CCLOG("width = %f height = %f, pEGLView->getFrameSize", size.width, size.height);
	size = pEGLView->getDesignResolutionSize();
	CCLOG("width = %f height = %f, pEGLView->getDesignResolutionSize", size.width, size.height);
	size = pEGLView->getVisibleSize();
	CCLOG("width = %f height = %f, pEGLView->getVisibleSize", size.width, size.height);
	

增加了一行代码 pDirector->setContentScaleFactor(2.0f);这个函数从字面上的解释是设置缩放因子，参数为2，输出调试信息如下：

这个函数影响了pDirector->getWinSizeInPixels也就是说，让窗口的分辨率变大了，其他没变，这里的分辨率是cocos2dx自定义的这种分辨率，和屏幕分辨率没有关系

这样的话，程序运行的结果也变化了

对比以前没有这句话的程序结果：

我们发现480x320的图片，在setContentScaleFactor之后变小了，事实上不是图片变小了，而是窗口的分辨率变大了而已。

按钮之类的也变小了，都变成了一半大小，所以getWinSizeInPixels返回的是窗口的分辨率大小，而这个分辨率大小受

setContentScaleFactor影响。

其实我们通过cocos2dx源代码也可以看到这点：

CCSize CCDirector::getWinSize(void)
{
    return m_obWinSizeInPoints;
}

CCSize CCDirector::getWinSizeInPixels()
{
    return CCSizeMake(m_obWinSizeInPoints.width * m_fContentScaleFactor, m_obWinSizeInPoints.height * m_fContentScaleFactor);
}