LineDDA的一个例子

unit Unit1;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, ExtCtrls, StdCtrls, Buttons;

type

TfmMain = class(TForm)

procedure FormPaint(Sender: TObject);

end;

var

fmMain: TfmMain;

A: Byte;

implementation

uses math;

{$R *.dfm}

procedure c(X,Y:Integer; ACanvas:TCanvas);stdcall;

begin

Inc(A,2);

ACanvas.Pen.Width := 5;

if Odd(A mod 31) then

ACanvas.Pen.Color := clWhite

else

ACanvas.Pen.Color := clBlack;

ACanvas.MoveTo(x,y);

ACanvas.LineTo(x,y);

end;

procedure TfmMain.FormPaint(Sender: TObject);

begin

LineDDA(0,20,width,20,@c,LongInt(Canvas));

LineDDA(0,0,width,Height,@c,LongInt(Canvas));

end;

end.