石英核心、核心图形和石英二维有什么不同?

I wonder if someone can distinguish precisely between these? For my understanding, Core Graphics is just a "Framework Package" which contains Quartz Core and Quartz 2D. But I'm not sure about if Quartz 2D actually is Quartz Core? Maybe someone can draw some lines there? What makes up the differences between these?I wonder if someone can distinguish precisely b