再学 GDI+[6] DrawPie - 绘制饼形

 

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.