已知圆心和起始点坐标如何画弧

[isabel1169]

已知圆心和起始点坐标并且沿逆时针方向如何画出圆弧

[fandh]

好像CDC的Arc就可以吧！

[zoulie]

BOOL Arc(
HDC hdc, // handle to device context
int nLeftRect, // x-coord of bounding rectangle's upper-left corner
int nTopRect, // y-coord of bounding rectangle's upper-left corner
int nRightRect, // x-coord of bounding rectangle's lower-right corner
int nBottomRect, // y-coord of bounding rectangle's lower-right corner
int nXStartArc, // first radial ending point
int nYStartArc, // first radial ending point
int nXEndArc, // second radial ending point
int nYEndArc // second radial ending point
);

Parameters
hdc
Handle to the device context where drawing takes place.
nLeftRect
Specifies the logical x-coordinate of the upper-left corner of the bounding rectangle.
Windows 95 and Windows 98: The sum of nLeftRect plus nRightRect must be less than 32768.

nTopRect
Specifies the logical y-coordinate of the upper-left corner of the bounding rectangle.
Windows 95 and Windows 98: The sum of nTopRect plus nBottomRect must be less than 32768.

nRightRect
Specifies the logical x-coordinate of the lower-right corner of the bounding rectangle.
Windows 95 and Windows 98: The sum of nLeftRect plus nRightRect must be less than 32768.

nBottomRect
Specifies the logical y-coordinate of the lower-right corner of the bounding rectangle.
Windows 95 and Windows 98: The sum of nTopRect plus nBottomRect must be less than 32768.

nXStartArc
Specifies the logical x-coordinate of the ending point of the radial line defining the starting point of the arc.
nYStartArc
Specifies the logical y-coordinate of the ending point of the radial line defining the starting point of the arc.
nXEndArc
Specifies the logical x-coordinate of the ending point of the radial line defining the ending point of the arc.
nYEndArc
Specifies the logical y-coordinate of the ending point of the radial line defining the ending point of the arc.

[写不动代码的人]

BOOL Arc( LPCRECT lpRect, POINT ptStart, POINT ptEnd );
lpRect

Specifies the bounding rectangle (in logical units). You can pass either an LPRECT or a CRect object for this parameter.

ptStart

Specifies the x- and y-coordinates of the point that defines the arc’s starting point (in logical units). This point does not have to lie exactly on the arc. You can pass either a POINT structure or a CPoint object for this parameter.

ptEnd

Specifies the x- and y-coordinates of the point that defines the arc’s ending point (in logical units). This point does not have to lie exactly on the arc. You can pass either a POINT structure or a CPoint object for this parameter.

这个可以