再学 GDI+[6] DrawPie - 绘制饼形[转]

unit Unit1;

 

interface

 

uses

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

  Dialogs, StdCtrls, Spin, ExtCtrls;

 

type

  TForm1 = class(TForm)

    Panel1: TPanel;

    Label1: TLabel;

    Label2: TLabel;

    SpinEdit1: TSpinEdit;

    SpinEdit2: TSpinEdit;

    procedure FormCreate(Sender: TObject);

    procedure FormPaint(Sender: TObject);

  end;

 

var

  Form1: TForm1;

 

implementation

 

{$R *.dfm}

 

uses GDIPOBJ, GDIPAPI;

 

var

  a1,a2: Integer;

 

procedure TForm1.FormCreate(Sender: TObject);

begin

  a1 := 0;

  a2 := 30;

  SpinEdit1.Text := IntToStr(a1);

  SpinEdit2.Text := IntToStr(a2);

  SpinEdit1.Increment := 10;

  SpinEdit2.Increment := 10;

  SpinEdit1.OnChange := FormPaint;

  SpinEdit2.OnChange := FormPaint;

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, 30);

 

  g.DrawPie(p, x, y, w, h, a1, a2);

 

  g.Free;

  p.Free;

end;

 

end.