再学 GDI+[5] DrawArc - 绘制弧线

 

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.