【安卓笔记】图片特效之底片效果

package com.example.graphicsdemo1;
import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
public class MainActivity extends Activity implements OnClickListener
{
    private Button but_old = null;
    private Button but_func = null;
    private ImageView iv_show = null;
    
    @Override
    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        but_func = (Button) findViewById(R.id.but_func);
        but_old = (Button) findViewById(R.id.but_old);
        iv_show = (ImageView) findViewById(R.id.iv_show);
        
        but_func.setOnClickListener(this);
        but_old.setOnClickListener(this);
    }
    
    @Override
    public void onClick(View v)
    {
        if(v.getId() == R.id.but_func)
        {
            func();
        }else if(v.getId() == R.id.but_old)
        {
            iv_show.setImageResource(R.raw.girl);
        }
    }
    
    /**
     * 底片效果
     * 注意图片分辨率不能太高防止oom
     */
    public void func()
    {
        //原图
        Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.raw.girl);
        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        //创建可写的bitmap
        Bitmap base = Bitmap.createBitmap(width,height,bitmap.getConfig());
        Paint paint = new Paint();//新建画笔
//        paint.setStrokeWidth(1);
        
//        新建画布
        Canvas canvas = new Canvas(base);
        canvas.drawBitmap(bitmap, new Matrix(), paint);
        for(int i = 0; i < width; i++)
        {
            for(int j = 0; j < height; j++)
            {
                int color = bitmap.getPixel(i,j);
                int r = Color.red(color);
                int g = Color.green(color);
                int b = Color.blue(color);
                int a = Color.alpha(color);
                //修改图片每个点的像素的rgb值
                base.setPixel(i,j, Color.argb(a, 255-r, 255-g, 255-b));
            }
        }
        bitmap.recycle();
        iv_show.setImageBitmap(base);
    }
}