Easing is animating with a specified acceleration to make the animations smooth. Ease actions are a good way to fake physics in your game. If you use easing actions with your animations, your game looks more natural with smoother animations.
Let's move a Sprite object from (200,200) to (500,200) with acceleration and deceleration.
auto sprite = Sprite::create("res/run_01.png");
sprite->setPosition(Vec2(200, 200));
this->addChild(sprite);
auto move = MoveTo::create(3.0f, Vec2(500, 200));
auto ease = EaseInOut::create(move, 2.0f);
sprite->runAction(ease);Next, let's drop a Sprite object from the top of the screen and make it bounce.
auto sprite = Sprite::create("res/run_01.png");
sprite->setPosition(Vec2(size.width/2, size.height));
sprite->setAnchorPoint(Vec2(0.5f, 0.0f));
this->addChild(sprite);
auto drop = MoveTo::create(3.0f, Vec2(size.width/2, 0));
auto ease = EaseBounceOut::create(drop);
sprite->runAction(ease);