再學 GDI+[35]: TGPPen - 虛線畫筆位移 - SetDashOffset

　本例效果圖:

　　代碼文件:unit Unit1;
interface
uses
　Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
　Dialogs, ExtCtrls;
type
　TForm1 = class(TForm)
　　Timer1: TTimer;
　　procedure FormPaint(Sender: TObject);
　　procedure Timer1Timer(Sender: TObject);
　　procedure FormCreate(Sender: TObject);
　end;
var
　Form1: TForm1;
implementation
{$R *.dfm}
uses GDIPOBJ, GDIPAPI;
var
　n: Integer;
procedure TForm1.FormCreate(Sender: TObject);
begin
　Timer1.Interval := 100;
end;
procedure TForm1.FormPaint(Sender: TObject);
var
　g: TGPGraphics;
　p: TGPPen;
begin
　g := TGPGraphics.Create(Canvas.Handle);
　p := TGPPen.Create(aclChocolate, 8);
　p.SetDashStyle(DashStyleDashDotDot);
　p.SetDashOffset(n);
　g.DrawLine(p, ClientWidth div 2, ClIEntHeight div 2, 0, 0);
　g.DrawLine(p, ClientWidth div 2, ClientHeight div 2, ClIEntWidth div 2, 0);
　g.DrawLine(p, ClientWidth div 2, ClientHeight div 2, ClIEntWidth, 0);
　g.DrawLine(p, ClientWidth div 2, ClientHeight div 2, ClientWidth, ClIEntHeight div 2);
　g.DrawLine(p, ClientWidth div 2, ClientHeight div 2, ClientWidth, ClIEntHeight);
　g.DrawLine(p, ClientWidth div 2, ClientHeight div 2, ClientWidth div 2, ClIEntHeight);
　g.DrawLine(p, ClientWidth div 2, ClientHeight div 2, 0, ClIEntHeight);
　g.DrawLine(p, ClientWidth div 2, ClientHeight div 2, 0, ClIEntHeight div 2);
　Dec(n);
　if n > Sqrt(Sqr(ClientWidth) + Sqr(ClIEntWidth)) then n := 0;
　p.Free;
　g.Free;
end;
procedure TForm1.Timer1Timer(Sender: TObject);
begin
　Repaint;
end;
end.窗體文件:object Form1: TForm1
　Left = 0
　Top = 0
　Caption = 'Form1'
　ClIEntHeight = 167
　ClIEntWidth = 242
　Color = clBtnFace
　Font.Charset = DEFAULT_CHARSET
　Font.Color = clWindowText
　Font.Height = -11
　Font.Name = 'Tahoma'
　Font.Style = []
　OldCreateOrder = False
　Position = poDesktopCenter
　OnCreate = FormCreate
　OnPaint = FormPaint
　PixelsPerInch = 96
　TextHeight = 13
　object Timer1: TTimer
　　OnTimer = Timer1Timer
　　Left = 112
　　Top = 88
　end
end