package com.j2medev.chapter3;

import java.io.IOException;
import java.util.*;
import javax.microedition.lcdui.*;
import javax.microedition.lcdui.game.Sprite;

public class RotateCanvas extends Canvas{
    
    private Image img = null;
    //定義數組，其中包含了Sprite類中定義的所有翻轉的形式
    private int[] rotate= new int[]{Sprite.TRANS_MIRROR,Sprite.TRANS_MIRROR_ROT90,
            Sprite.TRANS_MIRROR_ROT180,Sprite.TRANS_MIRROR_ROT270,
            Sprite.TRANS_NONE,Sprite.TRANS_ROT90,Sprite.TRANS_ROT180,Sprite.TRANS_ROT270};
    //Timer和TimerTask用于制作幻燈片的效果
    private Timer timer = new Timer();        
    private int index = 0;

    public RotateCanvas() {
        try{
            img = Image.createImage("/city.png");
        }catch(IOException ex){
            ex.printStackTrace();
        }
        //更新totate數組的索引，然后重新繪制屏幕，形成幻燈片放映的效果
        timer.schedule(new TimerTask() {
            int i = 0;
            public void run() {
                //循環更新rotate數組索引
                index = (i++)%rotate.length;
                repaint();
            }
        },1000,1000);
        
    }
    
    public void paint(Graphics g){
        int color = g.getColor();
        g.setColor(0xFFFFFF);
        g.fillRect(0,0,getWidth(),getHeight());
        g.setColor(color);
        //midp 2.0中，drawRegion()是實現圖片翻轉的不錯選擇
        g.drawRegion(img,0,0,img.getWidth(),img.getHeight(),
                rotate[index],getWidth()/2,getHeight()/2,Graphics.HCENTER|Graphics.VCENTER);
    }
    
    public void hideNotify(){
        if(timer != null){
            timer.cancel();
            timer = null;
            img = null;
        }
    }
    
}