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//声明:
Arc(
  DC: HDC;                                {设备环境句柄}
  X1, Y1, X2, Y2, X3, Y3, X4, Y4: Integer {四个坐标点}
): BOOL;


//举例: procedure TForm1.FormPaint(Sender: TObject); const x1 = 10; y1 = 10; x2 = 200; y2 = 200; x3 = 130; y3 = 200; x4 = 160; y4 = 10; begin Canvas.TextOut(x1,y1, '1'); Canvas.TextOut(x2,y2, '2'); Canvas.TextOut(x3,y3, '3'); Canvas.TextOut(x4,y4, '4'); Arc(Canvas.Handle, x1,y1, x2,y2, x3,y3, x4,y4); end;
//效果图:

//书上的一个例子:
procedure TForm1.FormPaint(Sender: TObject);
var
  i: Integer;
  r: TRect;
begin
  r := Self.ClientRect;
  Canvas.Pen.Width := 2;

  for i := 1 to 5 do
  begin
    Arc(Canvas.Handle,
        r.Left, r.Top,
        r.Right, r.Bottom,
        r.Right, (r.Bottom - r.Top) div 2,
        r.Left, (r.Bottom - r.Top) div 2
    );

    InflateRect(r, -2, -2);                 {缩小矩形}
    Canvas.Pen.Color := PaletteIndex(i+10); {改变颜色}
  end;
end;

//效果图:

posted on 2008-02-09 17:33  万一  阅读(...)  评论(...编辑  收藏