Cocos2d-x 3 way to extract Image data from texture2D if i loaded plist file into SpriteFrameCache

cocos2d-x C++
#1

i try to detect image data for alpha pixel detection for this i need Image Data
i have loaded 2 fame animation into cache and i Dont what to load the image again
and now that renderTextureWithWidthAndHeight is not in CCRenderTexture
using :

CCImage *testImage = new CCImage;
testImage->initWithImageFile(textureName);
unsigned char *data = testImage->getData();

how can i extract the Image info from this code :

m_frameCache = SpriteFrameCache::getInstance();
m_frameCache->addSpriteFramesWithFile("Blocks/sprites.plist");

// create animation "click"
SpriteFrame* frame_no_shadow = m_frameCache->getSpriteFrameByName("motion_block_no_shadow.png");
SpriteFrame* frame_shdow = m_frameCache->getSpriteFrameByName("motion_block_shadow.png");
Vector<SpriteFrame*> animFrames(2);
animFrames.pushBack(frame_no_shadow);
animFrames.pushBack(frame_shdow);
auto animation = Animation::createWithSpriteFrames(animFrames, 0.2f);
// Add an animation to the Cache
AnimationCache::getInstance()->addAnimation(animation, "drop_shadow");

SpriteFrame* frame = this->m_frameCache->getSpriteFrameByName("motion_block_no_shadow.png");
this->setSpriteFrame(frame);

im using as reference those links :
http://www.cocos2d-x.org/forums/6/topics/13787
http://www.cocos2d-x.org/forums/6/topics/19694