rei_27.pas

Delphi经典游戏程序设计40例.pdf 中国铁道出版社出版 含源码

unit Rei_27;

interface

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

type
  TRei40_27 = class(TForm)
    Timer1: TTimer;
    MainMenu1: TMainMenu;
    Panel1: TPanel;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    ScrollBar1: TScrollBar;
    ScrollBar2: TScrollBar;
    ScrollBar3: TScrollBar;
    Button1: TButton;
    procedure FormCreate(Sender: TObject);
    procedure Timer1Timer(Sender: TObject);
    procedure ScrollBar1Change(Sender: TObject);
    procedure ScrollBar2Change(Sender: TObject);
    procedure ScrollBar3Change(Sender: TObject);
    procedure Button1Click(Sender: TObject);
  private
    { Private 定义 }
  public
    { Public 定义 }
  end;

var
  Rei40_27: TRei40_27;

  Make_Bmap: TBitmap;

  //  定义各种变量（Byte类型、Integer类型、Single类型、TRect类型）
  St: Byte;
  Cheight, Cwidth, CT: Word;
  X, Y, DX, DY, MX, QX, b, c: Integer;
  a: Single;
  Rect_D: TRect;

implementation

{$R *.DFM}

procedure TRei40_27.FormCreate(Sender: TObject);
begin
  //  设定Form属性
  Rei40_27.Height := 480;
  Rei40_27.Width := 640;
  Cwidth := Rei40_27.ClientHeight;
  Cheight := Rei40_27.ClientHeight;
  Panel1.Width := 152;
  Label1.Height := 23;
  Label1.Left := 10;
  Label1.Top := 12;
  Label1.Width := 63;
  Label2.Height := 23;
  Label2.Left := 10;
  Label2.Top := 82;
  Label2.Width := 63;
  Label3.Height := 23;
  Label3.Left := 10;
  Label3.Top := 152;
  Label3.Width := 63;
  Edit1.Height := 23;
  Edit1.Left := 82;
  Edit1.Top := 10;
  Edit1.Width := 60;
  Edit2.Height := 23;
  Edit2.Left := 82;
  Edit2.Top := 80;
  Edit2.Width := 60;
  Edit3.Height := 23;
  Edit3.Left := 82;
  Edit3.Top := 150;
  Edit3.Width := 60;
  ScrollBar1.Height := 16;
  ScrollBar1.Left := 10;
  ScrollBar1.Top := 45;
  ScrollBar1.Width := 135;
  ScrollBar2.Height := 16;
  ScrollBar2.Left := 10;
  ScrollBar2.Top := 115;
  ScrollBar2.Width := 135;
  ScrollBar3.Height := 16;
  ScrollBar3.Left := 10;
  ScrollBar3.Top := 185;
  ScrollBar3.Width := 135;
  Button1.Height := 43;
  Button1.Left := 10;
  Button1.Top := 222;
  Button1.Width := 135;
  //  变量的初始设定
  St := 0;
  b := 120;
  c := 250;
  DX := 4;
  ScrollBar1.Position := b;
  ScrollBar2.Position := c;
  ScrollBar3.Position := DX;

  Make_Bmap := TBitmap.Create;
  Make_Bmap.Width := Cwidth;
  Make_Bmap.Height := Cheight;
end;

procedure TRei40_27.Timer1Timer(Sender: TObject);
begin
  case St of
    //  若St＝0则将画面与变量初始化
    0: begin
      Rect_D := Rect(0, 0, Cwidth, Cheight);
      Canvas.Brush.Color := clBlack;
      Canvas.FillRect(Rect_D);
      Make_Bmap.Canvas.Brush.Color := clBlack;
      Make_Bmap.Canvas.FillRect(Rect_D);
      Edit1.Text := ' ' + IntToStr(b * 2);
      Edit2.Text := ' ' + IntToStr(c);
      Edit3.Text := ' ' + IntToStr(DX);
      if DX < 0 then
      begin
        X := Cwidth div 2 + b;
        MX := b;
      end
      else begin
        X := Cwidth div 2 - b;
        MX := -b;
      end;
      a := -c / (b * b);
      if a < 0 then
        Y := 0
      else
        Y := Cheight;
      St := 1;
    end;
    //  若St＝1则进行座标计算并显示点
    1: begin
      QX := MX;
      MX := MX + DX;
      DY := Round(a * (MX * MX - QX * QX));
      X := X + DX;
      Y := Y + DY;
      Canvas.Pixels[X, Y] := clWhite;
      Canvas.Pixels[X + 1, Y] := clWhite;
      if (X <= 0) or (X >= Cwidth) then
        St := 2;
    end;
  end;
end;

procedure TRei40_27.ScrollBar1Change(Sender: TObject);
begin
  //  全宽度(bx2)的指定
  b := ScrollBar1.Position;
  Edit1.Text := ' ' + IntToStr(b * 2);
end;

procedure TRei40_27.ScrollBar2Change(Sender: TObject);
begin
  //  顶点高度(c)的指定
  c := ScrollBar2.Position;
  Edit2.Text := ' ' + IntToStr(c);
end;

procedure TRei40_27.ScrollBar3Change(Sender: TObject);
begin
  //  X变化量(DX)的指定
  DX := ScrollBar3.Position;
  Edit3.Text := ' ' + IntToStr(DX);
end;

procedure TRei40_27.Button1Click(Sender: TObject);
begin
  //  开始的指示
  St := 0;
end;

end.