LineDDA info  Overview  Group

The LineDDA function determines which pixels should be highlighted for a line defined by the specified starting and ending points.

BOOL LineDDA(

int nXStart,	// x-coordinate of line’s starting point
int nYStart,	// y-coordinate of line’s starting point
int nXEnd,	// x-coordinate of line’s ending point
int nYEnd,	// y-coordinate of line’s ending point
LINEDDAPROC lpLineFunc,	// address of application-defined callback function
LPARAM lpData	// address of application-defined data
);

Parameters

nXStart

Specifies the x-coordinate of the line’s starting point.

nYStart

Specifies the y-coordinate of the line’s starting point.

nXEnd

Specifies the x-coordinate of the line’s ending point.

nYEnd

Specifies the y-coordinate of the line’s ending point.

lpLineFunc

Specifies the address of an application-defined callback function. For more information, see the LineDDAProc callback function.

lpData

Points to the application-defined data.

Return Values

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero. To get extended error information, call GetLastError.

Remarks

The LineDDA function passes the coordinates for each point along the line, except for the line’s ending point, to the application-defined callback function. In addition to passing the coordinates of a point, this function passes any existing application-defined data.

The coordinates passed to the callback function match pixels on a video display only if the default transformations and mapping modes are used.

See Also

LineDDAProc