startscreen.java

是一个applet小游戏

import java.applet.Applet;
import java.awt.*;


class StartScreen
{

   int     width,height;
   int     ImageLeftBound,ImageRightBound,ImageX,ImageY,ImageWidth,
           ImageHeight,VX;
   Font    F1,F2;
   Image   Image1,Image2,currentImage;
   String  ChineseTitle,tsTitle;
   Applet  Game;
   boolean showPressEnter;
   int     js;

   public StartScreen(int AppletWidth,int AppletHeight,Applet Game,
                      Image Image1,Image Image2)
   {//开始界面
      F1     = new Font("TimesRoman",Font.BOLD + Font.ITALIC,50);
      F2     = new Font("TimesRoman",Font.BOLD,20);

      ChineseTitle    = "飞机大战";
      tsTitle    = "按回车开始，按ESC退出";

      width           = AppletWidth;
      height          = AppletHeight;

      this.Image1     = Image1;
      this.Image2     = Image2;

      ImageWidth      = Image1.getWidth(Game);
      ImageHeight     = Image1.getHeight(Game);
      ImageLeftBound  = 2;
      ImageRightBound = AppletWidth - (2 + ImageWidth);
      ImageX          = ImageRightBound;

      VX              = -1;
      this.Game       = Game;
      currentImage    = Image2;
      showPressEnter  = true;
      js=0;
   }

   public void UpdateStatus()
   {
      ImageX = ImageX + VX;

      if(ImageX <= ImageLeftBound)
      {
         currentImage = Image1;

         ImageX = ImageLeftBound;
         VX     = -VX;
      }

      if(ImageX >= ImageRightBound)
      {
         currentImage = Image2;

         ImageX = ImageRightBound;
         VX     = -VX;
         js++;
         if(js==2){
         js=0;}
      }
   }

   public void paintScreen(Graphics g)
   {
      int bj,yd;
      g.setFont(F1);
      g.setColor(Color.blue);    //字体颜色
      g.drawString(ChineseTitle,90,40); //中英文标题
      g.setColor(Color.red);    //字体颜色
      g.setFont(F2);
      g.drawString(tsTitle,92,280);

      //ImageY       = Y + Descent + 30;
      //直线
     // ImageY       = Y +10+ImageX/2;
      if (js==0){
            if (VX>0)
             {
                  ImageY=100-(int)(Math.sin((ImageX-ImageLeftBound)*6.28/(ImageRightBound-ImageLeftBound))*100);
             }
            else
             {
                  ImageY= 100-(int)(Math.cos((ImageX-ImageLeftBound)*6.28/(ImageRightBound-ImageLeftBound)+1.57)*100);
             }
      }else if (js==1){
            bj=(ImageRightBound-ImageLeftBound)/2;
            yd=(ImageRightBound+ImageLeftBound)/2;
            if (VX>0)
             {
                  ImageY= 100-(int)(Math.sqrt(bj*bj-(yd-ImageX)*(yd-ImageX))*0.6);
             }
            else
             {
                  ImageY= 100+(int)Math.sqrt(bj*bj-(yd-ImageX)*(yd-ImageX));
             }
      }
      g.drawImage(currentImage,ImageX,ImageY,Game);
   }
}