安卓图片缩放

package com.example.test;



import android.app.Activity;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.os.Bundle;
import android.view.View;

public class MainActivity extends  Activity {

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(new MyView(getApplicationContext()));
	}

 
	
}

class MyView extends View{

	public MyView(Context context) {
		super(context);
	}
	
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);
		//原始图片
		Bitmap originalBitmap=BitmapFactory.decodeResource(getResources(), R.drawable.img);
		System.out.println(originalBitmap.getWidth()+"  "+originalBitmap.getHeight());
		
		
		canvas.drawBitmap(originalBitmap, 0,0, null);
		
		
		//下面代码生成原图宽高各为一半的bitmap
		
		int pixels[]=new int[originalBitmap.getWidth()*originalBitmap.getHeight()];
		//获取原图像素
		originalBitmap.getPixels(pixels, 0, originalBitmap.getWidth(), 0, 0, originalBitmap.getWidth(), originalBitmap.getHeight());
		
		int newPixels[]=new int[   (originalBitmap.getWidth()/2)  *  (originalBitmap.getHeight()/2) ];
		
		//把奇数行奇数列交叉点对应的像素依次放到newPixels中
		for (int i = 1; i < originalBitmap.getHeight()	; i+=2) {
			
			for (int j = 1; j < originalBitmap.getWidth(); j+=2) {
				
				newPixels[  i/2*  (originalBitmap.getWidth()/2) +j/2 ]=pixels[ i*originalBitmap.getWidth()+j ];
			}
		}
		
		//生成新图片
		Bitmap scaleHalfBmp=Bitmap.createBitmap(newPixels, originalBitmap.getWidth()/2, originalBitmap.getHeight()/2, Config.ARGB_8888);
		
		canvas.translate(0, originalBitmap.getHeight()+20);
		
		canvas.drawBitmap(scaleHalfBmp, 0, 0, null);
		
		
		/////////////////放大/////////////////////////////////
		
		int scale2Width=scaleHalfBmp.getWidth()*2;
		
		int scale2Height=scaleHalfBmp.getHeight()*2;
		
		int scale2pixels[]=new int[scale2Width *scale2Height];
		
		for (int i = 0; i <scale2Height; i++) {
			for (int j = 0; j < scale2Width; j++) {
				scale2pixels[i*scale2Width+j]=newPixels[ i/2*scaleHalfBmp.getWidth() + j/2 ];
			}
		}
		
//		for (int i = 0; i < scaleHalfBmp.getHeight(); i++) {
//			for (int j = 0; j < scaleHalfBmp.getWidth(); j++) {
//				scale2pixels[ i*2*scale2Width+ j*2 ]=newPixels[i*scaleHalfBmp.getWidth()+j];
//			}
//		}
		Bitmap bmp=Bitmap.createBitmap(scale2pixels, scale2Width, scale2Height, Config.ARGB_8888);
		
		canvas.translate(0, scaleHalfBmp.getHeight()+10);
		
		canvas.drawBitmap(bmp, 0, 0, null);
		
		
		
	}
	
}