再学 GDI+[5] DrawArc - 绘制弧线[转]

unit Unit1;

 

interface

 

uses

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

  Dialogs, StdCtrls, Spin, ExtCtrls;

 

type

  TForm1 = class(TForm)

    Panel1: TPanel;

    SpinEdit1: TSpinEdit;

    SpinEdit2: TSpinEdit;

    Label1: TLabel;

    Label2: TLabel;

    procedure FormPaint(Sender: TObject);

    procedure FormCreate(Sender: TObject);

  private

    { Private declarations }

  public

    { Public declarations }

  end;

 

var

  Form1: TForm1;

 

implementation

 

{$R *.dfm}

uses

  GDIPAPI,GDIPOBJ;

var

  a1,a2:Integer;

procedure TForm1.FormCreate(Sender: TObject);

begin

  a1:=0;

  a2:=360;

  SpinEdit1.Text:=IntToStr(a1);

  SpinEdit2.Text:=IntToStr(a2);

  SpinEdit1.Increment:=10;

  SpinEdit2.Increment:=10;

 

end;

 

procedure TForm1.FormPaint(Sender: TObject);

var

  g:TGPGraphics;

  p:TGPPen;

  x,y,w,h: Integer;

begin

  g:=TGPGraphics.Create(Canvas.Handle);

  p:=TGPPen.Create(aclRed,2);

  g.Clear(aclWhite);

 

  x := ClientWidth div 6;

  y := ClientHeight div 6;

  w := x * 4;

  h := y * 3;

 

  a1:=StrToIntDef(SpinEdit1.Text,0);

  a2:=StrToIntDef(SpinEdit2.Text,360);

 

 

  g.DrawArc(p,x,y,w,h,a1,a2);

 

  p.Free;

  g.Free;

end;

 

end.