I'm not very 'well up' on the theatre, but those are the 'standard' SEAC roundels. (South East Asia Command). They originated as the blue/white/red RAF roundel, and the red centre was removed to avoid any possible confusion, at a distance, with the Japanese 'meatball' roundel. The size was reduced, and, on certain coloured backgrounds, to make them more visible, a white outline was added.
I'm not sure, but I think the bars were added, and the roundel enlarged, at about the time the US introduced 'bars to the stars'. This was to make the entire marking appear as a rectangle at a distance, rather than a blur of a disc or square. As to specific area requirements, I don't know, as I know the SEAC roundel was still used in some areas, even when the bars and roundels were also being used.
Hope this helps a bit.