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);

}

}