Is this code, for horizontal page curl in iPhone, valid?
问题 I was Googling for applying horizontal page curl in iPhone. I also tried this, but it wasn't appropriate for me (To change orientation and work in different ori.). I tried to search the web more. Finally I got this link. From where, I could understand the horizontal page curl. But when I went to code deeply, I found some confusing points: extern NSString *kCAFilterPageCurl; // From QuartzCore.framework is it valid to use internal variable ? ( as it's mentioned - from QuartzCore ) CAFilter