Question

pDC->Ellipse(CRect(npoint.x-i,npoint.y-i,npoint.x+i,npoint.y+i)); pDC->Ellipse 和 CRect 怎么用????

Answer 1

左上角和右下角的坐标

CDC::Ellipse
BOOL Ellipse( int x1, int y1, int x2, int y2 );

BOOL Ellipse( LPCRECT lpRect );

Return Value

Nonzero if the function is successful; otherwise 0.

Parameters

x1

Specifies the logical x-coordinate of the upper-left corner of the ellipse’s bounding rectangle.

y1

Specifies the logical y-coordinate of the upper-left corner of the ellipse’s bounding rectangle.

x2

Specifies the logical x-coordinate of the lower-right corner of the ellipse’s bounding rectangle.

y2

Specifies the logical y-coordinate of the lower-right corner of the ellipse’s bounding rectangle.

lpRect

Specifies the ellipse’s bounding rectangle. You can also pass a CRect object for this parameter

Answer 2

先用CRect确定矩形left、top、right和bottom位置，再用Ellipse根据矩形位置画椭圆