The flags parameter passed to the QADrawContextNew function specifies a set of bit flags that control features of the new draw context. You can use these masks to configure the flags parameter.
#define kQAContext_None 0
#define kQAContext_NoZBuffer (1 << 0)
#define kQAContext_DeepZ (1 << 1)
#define kQAContext_DoubleBuffer (1 << 2)
#define kQAContext_Cache (1 << 3)