if (redrawMethod & RS2::RedrawGrid)

...

if (redrawMethod & RS2::RedrawDrawing)

...

if (redrawMethod & RS2::RedrawOverlay)

...

RedrawNone = 0

RedrawGrid = 1

RedrawOverlay = 2

RedrawDrawing = 4

RedrawAll = 0xffff

https://en.wikipedia.org/wiki/Bitwise_operation#ANDI don't understand the point of these expressions.

If 0xffff & 2 evaluates to true, then 0xffff alone will evaluate to true.

If 0 & 2 evaluates to false, then 0 alone will evaluate to false.

Isn't the right side superfluous?

In otherwords, can't we just simplify it to one condition: if (redrawMethod) ?