LineDDA

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,  // pointer to callback function
  LPARAM lpData            // pointer to 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

Pointer to an application-defined callback function. For more information, see the LineDDAProc callback function.

lpData

Pointer 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.

Windows NT: 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.

QuickInfo

  Windows NT: Requires version 3.1 or later.
  Windows: Requires Windows 95 or later.
  Windows CE: Unsupported.
  Header: Declared in wingdi.h.
  Import Library: Use gdi32.lib.

See Also

Lines and Curves Overview, Line and Curve Functions, LineDDAProc