cocos2d-x 地图的单指拖动和双指放大和缩小 的简单实现

原理： 

1）： 判断点击时是单指还是双指，然后再move中进行移动放大和缩小的操作

            注意： ccTouchesBegan()和ccTouchesMoved()函数，它的意思是点击几次，就有几次ccTouchesBegan事件，并且当你点击，但没有进行移动时，也会响应ccTouchesMoved事件，你们可以试试看。

2）： 放大和缩小时的地图的锚点的设置： 首先记录下地图的contentSize，还有初始原点位置，还有锚点位置。

实现：

HelloWorldScene.h

//点击事件
	virtual void ccTouchesBegan(CCSet *pTouches, CCEvent *pEvent);
	virtual void ccTouchesMoved(CCSet *pTouches, CCEvent *pEvent);
	virtual void ccTouchesEnded(CCSet *pTouches, CCEvent *pEvent);

	//两只手指点击时的初始距离
	float distance;

	//背景图
	CCSprite* sBg;

	//放大的倍数
	float m_scale; 

	//记录原点位置
	CCPoint bgOrigin;

	//存touch事件
	CCDictionary* _touchesDic;

HelloWorldScene.cpp

init():

//初始化背景
    sBg = CCSprite::create("bg.jpg");
	sBg->setAnchorPoint(CCPointZero);
    sBg->setPosition( CCPointZero );
    this->addChild(sBg, 0);
	//原点位置
	bgOrigin = CCPointZero;
	
    //初始化数据
	m_scale = 1.0f;
	distance = 0.0f;
	_touchesDic = CCDictionary::create();
	_touchesDic->retain();

	//设置可以点击
	this->setTouchEnabled(true);

ccTouchesBegan (): 

CCSetIterator iter = pTouches->begin();
	for (; iter != pTouches->end(); iter++){
		CCTouch* pTouch = (CCTouch*)(*iter);
		_touchesDic->setObject(pTouch, CCString::createWithFormat("%d",pTouch->getID())->getCString());
	}

	//两个手指
	if (_touchesDic->count() == 2){
		CCArray* keys = _touchesDic->allKeys();
		CCTouch *touch1 = (CCTouch*)_touchesDic->objectForKey(((CCString*)keys->objectAtIndex(0))->getCString());
		CCTouch *touch2 = (CCTouch*)_touchesDic->objectForKey(((CCString*)keys->objectAtIndex(1))->getCString());

		CCPoint pt = touch1->getLocation();
		CCPoint pt2 = touch2->getLocation();

		distance = ccpDistance(pt,pt2);
	} 

ccTouchesMoved():

if (_touchesDic->count() == 2) {
		CCArray* keys = _touchesDic->allKeys();
		CCTouch *touch1 = (CCTouch*)_touchesDic->objectForKey(((CCString*)keys->objectAtIndex(0))->getCString());
		CCTouch *touch2 = (CCTouch*)_touchesDic->objectForKey(((CCString*)keys->objectAtIndex(1))->getCString());

		CCPoint point1 = touch1->getLocation();
		CCPoint point2 = touch2->getLocation();

		//点击点距原点距离
		CCPoint mPoint1 = ccpSub(point1,bgOrigin);
		CCPoint mPoint2 = ccpSub(point2,bgOrigin);

		//点击点的中心点
		float x = (mPoint2.x+mPoint1.x)/2 ;  
		float y = (mPoint2.y+mPoint1.y)/2 ;

		//得到锚点值 
		CCSize bgSize = sBg->getContentSize();
		float anchorX = x/(bgSize.width*sBg->getScale());
		float anchorY = y/(bgSize.height*sBg->getScale());
		CCLOG("bg anchor: %lf,%lf",anchorX,anchorY);
		sBg->setAnchorPoint(ccp(anchorX,anchorY));

		//位置
		x = (point2.x+point1.x)/2 ;  
		y = (point2.y+point1.y)/2 ;
		sBg->setPosition(ccp(x,y));

		//放大的倍率
		float mdistance = ccpDistance(mPoint1,mPoint2);
		m_scale = (mdistance/distance)*m_scale;
		if (m_scale>=3.0)//放大缩小的最值
		{
			sBg->setScale(3.0f);
		}
		else if (m_scale<=1.0)
		{
			sBg->setScale(1.0f);
		}
		else
		{
			distance = mdistance;
			sBg->setScale(m_scale);
		}
		m_scale = sBg->getScale();

		//原点值
		bgOrigin  = ccpSub(ccp(x,y),ccp(bgSize.width*sBg->getScale()*anchorX,bgSize.height*sBg->getScale()*anchorY));


	}
	else if (_touchesDic->count() == 1)//单指
	{
		CCSetIterator iter = pTouches->begin();  
		CCPoint pDelta = ((CCTouch*)(*iter))->getDelta();
		CCPoint postion = sBg->getPosition();
		sBg->setPosition(ccpAdd(postion, pDelta));

		//原点位置
		bgOrigin = ccpAdd(bgOrigin,pDelta);
	}
	else
	{

	}

ccTouchesEnded():

//恢复原值

if (_touchesDic->count() == 2) {
		distance = 0.0f;
	} else {
		
	}

	CCSetIterator iter = pTouches->begin();
	for (; iter != pTouches->end(); iter++){
		CCTouch* pTouch = (CCTouch*)(*iter);
		_touchesDic->removeObjectForKey(CCString::createWithFormat("%d",pTouch->getID())->getCString());
	}

这样差不多就可以实现单指拖动，双指放大和缩小

该项目代码下载（Android版本）地址：

http://download.youkuaiyun.com/detail/cwn0812/6642203