I'm still using cocos 0.8 and I'm a little too far along in my development to update to 0.9. Instead, I've been using Joao's great AtlasTextureReader code to read the Zwoptex files (http://www.copypastecode.com/8695/).
However, I need to update the getSpriteRect function to take into account the texture offsets. My question is... what exactly is the offset value? Shouldn't it be the number of pixels trimmed from the original image size? So what exactly is the value being generated by Zwoptex?