CRgn

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CRgn Class

Description

The class responsible for creating and managing regions.

CRgn Members

Initialization and Assignment

CRgn

CRgn();

CRgn(HRGN hRgn);

Constructs a CRgn object.

FromHandle

static CRgn* FromHandle(HRGN hRgn);

Returns the CRgn associated with the specified region handle. If a CRgn object doesn't already exist, a temporary CRgn object is created. This temporary CRgn will be deleted sometime after the processing of the current message is complete. operator HRGN()

operator HRGN() const;

Allows a CRgn object to be used as a region handle (HRGN). Attributes GetRegionData

int GetRegionData(LPRGNDATA lpRgnData, int nDataSize) const;

Fills the specified buffer with data describing a region. GetRgnBox

int GetRgnBox(RECT& rc) const;

Retrieves the bounding rectangle of the region, and stores it in the specified RECT. The return value indicates the region's complexity: NULLREGION;SIMPLEREGION; or COMPLEXREGION. Operations CombineRgn

int CombineRgn(HRGN hRgnSrc1, HRGN hRgnSrc2, int nCombineMode);

int CombineRgn(HRGN hRgnSrc, int nCombineMode);

Combines two sepcified regions and stores the result. CopyRgn

int CopyRgn(HRGN hRgnSrc);

Assigns the specified region to the current region. CreateEllipticRgn

HRGN CreateEllipticRgn(int x1, int y1, int x2, int y2);

Creates an elliptical region. CreateEllipticRgnIndirect

HRGN CreateEllipticRgnIndirect(const RECT& rc);

Creates an elliptical region. CreateFromData

HRGN CreateFromData(const XFORM* lpXForm, int nCount, 
                    const RGNDATA* pRgnData);

Creates a region from the specified region and transformation data. CreateFromPath

HRGN CreateFromPath(HDC hDC);

Creates a region from the path that is selected into the specified device context. The resulting region uses device coordinates. CreatePolygonRgn

HRGN CreatePolygonRgn(LPPOINT lpPoints, int nCount, int nMode);

Creates a polygonal region. CreatePolyPolygonRgn

HRGN CreatePolyPolygonRgn(LPPOINT lpPoints, LPINT lpPolyCounts, 
                          int nCount, int nPolyFillMode);

Creates a region consisting of a series of polygons. EqualRgn

BOOL EqualRgn(HRGN hRgn) const;

Creates a region consisting of a series of polygons. The polygons can overlap. OffsetRgn

int OffsetRgn(int x, int y);

int OffsetRgn(POINT& pt);

Moves a region by the specified offsets. PtInRegion

BOOL PtInRegion(int x, int y) const;

BOOL PtInRegion(POINT& pt) const;

Determines whether the specified point is inside the specified region. RectInRegion

BOOL RectInRegion(const RECT& rc) const;

Determines whether the specified rect is inside the specified region. SetRectRgn

void SetRectRgn(int x1, int y1, int x2, int y2);

void SetRectRgn(const RECT& rc);

Converts the region into a rectangular region with the specified coordinates.

Base class Members

For base class members, refer to the members of CGDIObject.

Remarks

CRgn objects can be used anywhere a a handle to a region (HRGN) might be used. They can be substituted for the HRGN in any of the Windows API functions which use a HRGN as a function argument. The benefit of using a CRgn object is that it automatically deletes the palette when it is destroyed.

Refer to the Graphics Device Interface section of Using Win32++ for additional information on using this class.

Summary Information

Header file	gdi.h
Win32/64 support	Yes
WinCE support	Yes