我們知道 Mac 中預覽圖片的時候可以使用多指觸控對圖片進行拉伸和旋轉。
在 iOS 中、我們可以讓手指在圖中的相對位置保持不變，從而將這三個操作統一起來，更方便的實現編輯功能。
To-do: 如何支持沿著一個方向的拉伸（三指？）
代碼：
首先定義支持編輯操作的
MySprite 類。
#define PB push_back
#define REP(i,n) for(int i=0,_##i=(n);i<_##i;++i )
#define PI 3.1415296
struct MySprite : public Sprite{
static MySprite* _target; static vector<Vec2> _pos; static vector<Node*> _pot;
static double _dist2, _atan2;
bool isMoveable, isZoomable, isRotatable;
void onTouchesBegan(const std::vector<Touch*>& touches, cocos2d::Event *event);
void onTouchesMoved(const std::vector<Touch*>& touches, cocos2d::Event *event);
void onTouchesEnded(const std::vector<Touch*>& touches, cocos2d::Event *event);
void onTouchesCancelled(const std::vector<Touch*>& touches, cocos2d::Event *event);
void init2(bool,bool,bool);
};
注意到不同於單點觸控、多點觸控的 onTouchesBegan() 方法似乎沒有返回函數、因此我們需要手動紀錄一下 _target。
當作用在多個對象上時，只操作最上層的。
_dist2 用來記錄兩指之間的距離，用來實現放大。
_atan2 用來記錄兩隻之間的角度，用來實現旋轉。
#include "HelloWorldScene.h"
#include "cocostudio/CocoStudio.h"
#include "ui/CocosGUI.h"
#include "Audio.h"
#include "Template.h"
#include "Global.h"
USING_NS_CC;
void addAroundEdge(Sprite* t){
Size s = t->getContentSize();
auto e = DrawNode::create();
auto radius = 1;
auto color = Color4F(0, 0, 0, 1.0f);
auto lb = Vec2(0, 0), rb = Vec2(s.width, 0);
auto lt = Vec2(0, s.height), rt = Vec2(s.width, s.height);
e->drawSegment(lb, rb, radius, color);
e->drawSegment(lb, lt, radius, color);
e->drawSegment(rb, rt, radius, color);
e->drawSegment(lt, rt, radius, color);
e->setName("edge");
t->addChild(e);
}
vector<Vec2> MySprite::_pos;
vector<Node*> MySprite::_pot;
MySprite* MySprite::_target;
DB MySprite::_atan2, MySprite::_dist2;
void MySprite::init2(bool _isMoveable = 1, bool _isZoomable = 1, bool _isRotatable = 1){
isMoveable = _isMoveable;
isZoomable = _isZoomable;
isRotatable = _isRotatable;
auto listener = EventListenerTouchAllAtOnce::create();
listener->onTouchesBegan = CC_CALLBACK_2(MySprite::onTouchesBegan, this);
listener->onTouchesMoved = CC_CALLBACK_2(MySprite::onTouchesMoved, this);
listener->onTouchesEnded = CC_CALLBACK_2(MySprite::onTouchesEnded, this);
_eventDispatcher->addEventListenerWithSceneGraphPriority(listener->clone(), this);
addAroundEdge(this);
}
static const Color3B* s_TouchColors[5] = {
&Color3B::YELLOW,
&Color3B::BLUE,
&Color3B::GREEN,
&Color3B::RED,
&Color3B::MAGENTA
};
struct TouchPoint : public Node
{
TouchPoint(const Vec2 &touchPoint, const Color3B &touchColor)
{
DrawNode* drawNode = DrawNode::create();
auto s = Director::getInstance()->getWinSize();
Color4F color(touchColor.r/255.0f, touchColor.g/255.0f, touchColor.b/255.0f, 1.0f);
drawNode->drawLine(Vec2(-s.width, 0), Vec2(s.width, 0), color);
drawNode->drawLine(Vec2(0, -s.height), Vec2(0, s.height), color);
drawNode->drawDot(Vec2(0, 0), 3, color);
addChild(drawNode);
}
static TouchPoint* touchPointWithParent(Node* pParent, const Vec2 &touchPoint, const Color3B &touchColor)
{
auto pRet = new (std::nothrow) TouchPoint(touchPoint, touchColor);
pRet->setContentSize(pParent->getContentSize());
pRet->setAnchorPoint(Vec2(0.0f, 0.0f));
pRet->autorelease();
return pRet;
}
};
void MySprite::onTouchesBegan(const std::vector<Touch*>& touches, Event *event)
{
auto target = static_cast<MySprite*>(event->getCurrentTarget());
for (auto &touch: touches)
{
auto location = touch->getLocation();
Point locationInNode = target->convertToNodeSpace(touch->getLocation());
Size s = target->getContentSize();
Rect rect = Rect(0, 0, s.width, s.height);
if (!rect.containsPoint(locationInNode)){
return;
}
}
if (_target != nullptr && _target != target) return;
for (auto &touch: touches)
{
auto location = touch->getLocation();
Point locationInNode = target->convertToNodeSpace(touch->getLocation());
Size s = target->getContentSize();
Rect rect = Rect(0, 0, s.width, s.height);
auto touchPoint = TouchPoint::touchPointWithParent(this, location, *s_TouchColors[touch->getID()%5]);
touchPoint->setName("touchPoint");
Global::game->addChild(touchPoint);
touchPoint->setPosition(location);
_pos.PB(location), _pot.PB(touchPoint);
}
_target = target;
if (_pos.size() == 2){
_dist2 = _pos[0].getDistance(_pos[1]);
Vec2 d = _pos[1] - _pos[0];
_atan2 = atan2(d.y, d.x);
}
}
void MySprite::onTouchesMoved(const std::vector<Touch*>& touches, Event *event)
{
auto target = static_cast<MySprite*>(event->getCurrentTarget());
if (target != _target) return;
if (_pos.empty()) return;
vector<Vec2> new_pos;
for( auto &item: touches)
{
auto touch = item;
auto location = touch->getLocation();
Point locationInNode = target->convertToNodeSpace(touch->getLocation());
Size s = target->getContentSize();
Rect rect = Rect(0, 0, s.width, s.height);
new_pos.PB(location);
}
if (_pos.size() != new_pos.size()) return;
REP(i, _pos.size()){
_pot[i]->setPosition(new_pos[i]);
}
if (_pos.size() == 1){
target->setPosition(target->getPosition() + (new_pos[0] - _pos[0]));
_pos = new_pos;
}
else if (_pos.size() == 2){
auto target = static_cast<Sprite*>(event->getCurrentTarget());
auto new_dist2 = new_pos[0].getDistance(new_pos[1]);
target->setScale((DB)target->getScale()/_dist2*new_dist2);
_dist2 = new_dist2;
Vec2 d = new_pos[1] - new_pos[0];
DB new_atan2 = atan2(d.y, d.x);
target->setRotation( target->getRotation() - (new_atan2 - _atan2) / PI * 180);
_atan2 = new_atan2;
}
}
void MySprite::onTouchesEnded(const std::vector<Touch*>& touches, Event *event)
{
auto target = static_cast<MySprite*>(event->getCurrentTarget());
while (Global::game->getChildByName("touchPoint") != nullptr){
Global::game->getChildByName("touchPoint")->removeFromParent();
}
_pos.clear(); _pot.clear();
_target = nullptr;
}
void MySprite::onTouchesCancelled(const std::vector<Touch*>& touches, Event *event)
{
onTouchesEnded(touches, event);
}
void LongTouch::upd(){
if (counter > 0){
if (--counter == 0){
Audio::playSE("coin.mp3");
}
}
}
Scene* HelloWorld::createScene()
{
auto scene = Scene::create();
auto layer = HelloWorld::create();
scene->addChild(layer);
return scene;
}
void HelloWorld::update(float dt){
longTouch->upd();
return;
}
bool HelloWorld::init()
{
if ( !LayerColor::initWithColor(Color4B(255, 255, 255, 255)))
{
return false;
}
Global::game = this;
longTouch = new LongTouch;
auto size = Director::getInstance()->getWinSize();
auto t1 = static_cast<MySprite*>(Sprite::create("star_on.png")); t1->init2();
t1->setPosition(size / 2); addChild(t1);
auto t2 = static_cast<MySprite*>(Sprite::create("star_on.png")); t2->init2();
t2->setPosition(Vec2(size.width / 2 - 100, size.height / 2 - 100) ); addChild(t2);
auto t3 = static_cast<MySprite*>(Sprite::create("star_on.png")); t3->init2();
t3->setPosition(Vec2(size.width / 2 + 100, size.height / 2 + 100) ); addChild(t3);
return true;
}
