The ExtSelectClipRgn function combines the specified region with the current clipping region by using the specified mode.
int ExtSelectClipRgn(
HDC hdc, // handle to device context
HRGN hrgn, // handle to region
int fnMode // region-selection mode
);
| Value | Meaning |
|---|---|
| RGN_AND | The new clipping region combines the overlapping areas of the current clipping region and the region identified by hrgn. |
| RGN_COPY | The new clipping region is a copy of the region identified by hrgn. This is identical to SelectClipRgn. If the region identified by hrgn is NULL, the new clipping region is the default clipping region (the default clipping region is a null region). |
| RGN_DIFF | The new clipping region combines the areas of the current clipping region with those areas excluded from the region identified by hrgn. |
| RGN_OR | The new clipping region combines the current clipping region and the region identified by hrgn. |
| RGN_XOR | The new clipping region combines the current clipping region and the region identified by hrgn but excludes any overlapping areas. |
The return value specifies the new clipping region's complexity; it can be any one of the following values:
| Value | Meaning |
|---|---|
| NULLREGION | Region is empty. |
| SIMPLEREGION | Region is a single rectangle. |
| COMPLEXREGION | Region is more than one rectangle. |
| ERROR | An error occurred. |
If an error occurs when this function is called, the previous clipping region for the specified device context is not affected.
The ExtSelectClipRgn function assumes that the coordinates for the specified region are specified in device units.
Only a copy of the region identified by the hrgn parameter is used. The region itself can be reused after this call or it can be deleted.
Windows NT: Requires version 3.1 or later.
Windows: Requires Windows 95 or later.
Windows CE: Unsupported.
Header: Declared in wingdi.h.
Import Library: Use gdi32.lib.
Clipping Overview, Clipping Functions, SelectClipRgn