The RGNDATA structure contains a header and an array of rectangles that compose a region. The rectangles are sorted top to bottom, left to right. They do not overlap.
typedef struct _RGNDATA {
RGNDATAHEADER rdh;
char Buffer[1];
} RGNDATA;
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Requires version 1.0 or later.
Header: Declared in wingdi.h.
Regions Overview, Region Structures, RECT, RGNDATAHEADER