| int CombineRgn(hrgnDest, hrgnSrc1, hrgnSrc2, fnCombineMode) | |||||
| HRGN hrgnDest; | /* handle of destination region | */ | |||
| HRGN hrgnSrc1; | /* handle of source region | */ | |||
| HRGN hrgnSrc2; | /* handle of source region | */ | |||
| int fnCombineMode; | /* region combining mode | */ | |||
The CombineRgn function combines two existing regions and stores the result in a third region. The two regions are combined according to the given flag.
hrgnDest
Identifies a new region with dimensions that are defined by combining two other regions. (This region must exist prior to calling the CombineRgn function.)
hrgnSrc1
Identifies the first of two regions that will be combined to produce a new region.
hrgnSrc2
Identifies the second of two regions that will be combined to produce a new region.
fnCombineMode
Specifies how the two regions will be combined. It can be any one of the following values:
| Flag | Meaning |
| RGN_AND | The final region is the intersection of the two combined regions. |
| RGN_COPY | The final region is a copy of the region that is identified by hrgnSrc1. |
| RGN_DIFF | The final region consists of those parts of hrgnSrc1 which are not part of hrgnSrc2. |
| RGN_OR | The final region is the union of the two combined regions. |
| RGN_XOR | The final region is the union of the two combined regions except for the overlapping areas. |
The return value specifies the type of the resulting region. It can be any one of the following values:
| NULLREGION | New region is empty. |
| SIMPLEREGION | New region is a single rectangle. |
| COMPLEXREGION | New region is more than a single rectangle. |
| ERROR | No new region created. |
The three regions do not have to be distinct. For example hrgnSrc1 can equal hrgnDest.