CRgn::CreateEllipticRgn
Creates an elliptical region.
BOOL CreateEllipticRgn(
int x1,
int y1,
int x2,
int y2
);
Parameters
x1
Specifies the logical x-coordinate of the upper-left corner of the bounding rectangle of the ellipse.y1
Specifies the logical y-coordinate of the upper-left corner of the bounding rectangle of the ellipse.x2
Specifies the logical x-coordinate of the lower-right corner of the bounding rectangle of the ellipse.y2
Specifies the logical y-coordinate of the lower-right corner of the bounding rectangle of the ellipse.
Return Value
Nonzero if the operation succeeded; otherwise 0.
Remarks
The region is defined by the bounding rectangle specified by x1, y1, x2, and y2. The region is stored in the CRgn object.
The size of a region is limited to 32,767 by 32,767 logical units or 64K of memory, whichever is smaller.
When it has finished using a region created with the CreateEllipticRgn function, an application should select the region out of the device context and use the DeleteObject function to remove it.
Example
CRgn rgnA, rgnB, rgnC;
VERIFY(rgnA.CreateEllipticRgn(200, 100, 350, 250));
VERIFY(rgnB.CreateRectRgn( 0, 0, 50, 50 ));
VERIFY(rgnB.CopyRgn( &rgnA ));
int nOffsetResult = rgnB.OffsetRgn( -75, 75 );
ASSERT( nOffsetResult != ERROR && nOffsetResult != NULLREGION );
VERIFY(rgnC.CreateRectRgn( 0, 0, 1, 1));
int nCombineResult = rgnC.CombineRgn( &rgnA, &rgnB, RGN_AND );
ASSERT( nCombineResult != ERROR && nOffsetResult != NULLREGION );
CBrush brA, brB, brC;
VERIFY(brC.CreateHatchBrush( HS_FDIAGONAL, RGB(0, 0, 255) )); // Blue
VERIFY(pDC->FillRgn( &rgnC, &brC ));
VERIFY(brA.CreateSolidBrush( RGB(255, 0, 0) )); // rgnA Red
VERIFY(pDC->FrameRgn( &rgnA, &brA, 2, 2 ));
VERIFY(brB.CreateSolidBrush( RGB(0, 255, 0) )); // rgnB Green
VERIFY(pDC->FrameRgn( &rgnB, &brB, 2, 2 ));
Requirements
Header: afxwin.h