How to draw a part of Sprite and update it ?

cocos2d-x C++
#1

i have a sprite with height is 1204 ( than screen iphone)

I can draw a part this sprite in init method.
But i want when update, i can set rect sprite again ?

So how can i do that ?
Thanks for your support

#2

I think it has not been designed to work that way, but I suppose you could inherit from CCSprite and maybe override the setTextureCoords method.