GetRegionData function (wingdi.h)

The GetRegionData function fills the specified buffer with data describing a region. This data includes the dimensions of the rectangles that make up the region.

Syntax

DWORD GetRegionData(
  [in]  HRGN      hrgn,
  [in]  DWORD     nCount,
  [out] LPRGNDATA lpRgnData
);

Parameters

[in] hrgn

A handle to the region.

[in] nCount

The size, in bytes, of the lpRgnData buffer.

[out] lpRgnData

A pointer to a RGNDATA structure that receives the information. The dimensions of the region are in logical units. If this parameter is NULL, then the return value contains the number of bytes needed for the region data.

Return value

If the function succeeds and nCount specifies an adequate number of bytes, then the return value equals the actual number of bytes used (less than or equal to nCount).

If lpRgnData is NULL, then the return value is the required number of bytes.

If the function fails, then the return value is zero.

If the failure is due to hrgn being invalid, then GetLastError returns ERROR_INVALID_HANDLE. Otherwise, GetLastError returns ERROR_INVALID_PARAMETER .

If nCount is too small, then the function fails.

Remarks

The GetRegionData function is used in conjunction with the ExtCreateRegion function.

Requirements

See also

CreatePolyPolygonRgn

CreatePolygonRgn

CreateRectRgn

CreateRectRgnIndirect

CreateRoundRectRgn

ExtCreateRegion

RGNDATA

Region Functions

Regions Overview