Delphi编写星光效果

一 窗体设计

object Form1: TForm1
  Left = 0
  Top = 0
  Caption = 'Form1'
  ClientHeight = 397
  ClientWidth = 530
  Color = clNone
  Font.Charset = DEFAULT_CHARSET
  Font.Color = clWindowText
  Font.Height = -11
  Font.Name = 'Tahoma'
  Font.Style = []
  OldCreateOrder = False
  OnCreate = FormCreate
  OnDestroy = FormDestroy
  PixelsPerInch = 96
  TextHeight = 13
  object Image1: TImage
    Left = 2
    Top = 2
    Width = 7
    Height = 9
    Transparent = True
  end
  object Timer1: TTimer
    OnTimer = Timer1Timer
    Left = 270
    Top = 226
  end
end

二 实现代码

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls, ExtCtrls;

type
  TDot=record
    Pos:TPoint;
    Vel:TPoint;
  end;

  TForm1 = class(TForm)
    Timer1: TTimer;
    Image1: TImage;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure FormDestroy(Sender: TObject);
  private
    Dots:array[0..10] of TDot;
    offScreen:TBitmap;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.FormCreate(Sender: TObject);
var
  iCount:integer;
begin
  offScreen :=TBitmap.Create;
  offScreen.Width :=Form1.ClientWidth;
  offScreen.Height :=Form1.ClientHeight;
  for iCount := 0 to 9 do
  begin
    Dots[iCount].Pos.X :=Random(ClientWidth);
    Dots[iCount].Pos.Y :=Random(ClientHeight);
    if Random(2)=0 then
      Dots[iCount].Vel.X :=-1
    else
      Dots[iCount].Vel.X :=1;

    if Random(2)=0 then
      Dots[iCount].Vel.Y :=-1
    else
      Dots[iCount].Vel.Y :=1;
  end;
end;

procedure TForm1.FormDestroy(Sender: TObject);
begin
  offScreen.Free;
end;

procedure TForm1.Timer1Timer(Sender: TObject);
var
  iCount:integer;
begin
  offScreen.Canvas.Brush.Color :=clBlack;
  offScreen.Canvas.FillRect(offScreen.Canvas.ClipRect);
  for iCount := 0 to 9 do
  begin
    Dots[iCount].Pos.X :=Dots[iCount].Pos.X+Dots[iCount].Vel.X;
    Dots[iCount].Pos.Y :=Dots[iCount].Pos.Y+Dots[iCount].Vel.Y;
    if (Dots[iCount].Pos.X<0) or (Dots[iCount].Pos.X>ClientWidth) then
      Dots[iCount].Pos.X :=0-Dots[iCount].Vel.X;

    if (Dots[iCount].Pos.Y<0) or (Dots[iCount].Pos.Y>ClientHeight) then
      Dots[iCount].Pos.Y :=0-Dots[iCount].Vel.Y;

    offScreen.Canvas.Pixels[Dots[iCount].Pos.X,Dots[iCount].Pos.Y] :=clRed;
    offScreen.Canvas.Pixels[Dots[iCount].Pos.X+1,Dots[iCount].Pos.Y] :=clRed;
    offScreen.Canvas.Pixels[Dots[iCount].Pos.X,Dots[iCount].Pos.Y+1] :=clRed;
    offScreen.Canvas.Pixels[Dots[iCount].Pos.X+1,Dots[iCount].Pos.Y+1] :=clRed;
  end;
  ExcludeClipRect(Canvas.Handle,Image1.Left,Image1.Top,Image1.Left+Image1.Width,Image1.Top+Image1.Height);
  Canvas.Draw(0,0,offScreen);
end;

end.