LineDDA function (wingdi.h)

Article
10/13/2021

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

Syntax

BOOL LineDDA(
  [in] int         xStart,
  [in] int         yStart,
  [in] int         xEnd,
  [in] int         yEnd,
  [in] LINEDDAPROC lpProc,
  [in] LPARAM      data
);

Parameters

[in] xStart

Specifies the x-coordinate, in logical units, of the line's starting point.

[in] yStart

Specifies the y-coordinate, in logical units, of the line's starting point.

[in] xEnd

Specifies the x-coordinate, in logical units, of the line's ending point.

[in] yEnd

Specifies the y-coordinate, in logical units, of the line's ending point.

[in] lpProc

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

[in] data

Pointer to the application-defined data.

Return value

If the function succeeds, the return value is nonzero.

If the function fails, the return value is zero.

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.

Requirements

Requirement	Value
Minimum supported client	Windows 2000 Professional [desktop apps only]
Minimum supported server	Windows 2000 Server [desktop apps only]
Target Platform	Windows
Header	wingdi.h (include Windows.h)
Library	Gdi32.lib
DLL	Gdi32.dll