图片复古效果的实现

MainActivity.java

package com.example.huangxingli.androidshaderabout;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;

import android.graphics.Canvas;
import android.graphics.ColorMatrix;
import android.graphics.ColorMatrixColorFilter;
import android.graphics.Paint;

import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;

import android.widget.ImageView;



public class MainActivity extends ActionBarActivity {

    ImageView imageView;
    Bitmap mbitmap=null;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        imageView= (ImageView) findViewById(R.id.image);
        mbitmap= BitmapFactory.decodeResource(getResources(),R.drawable.a);
        imageView.setImageBitmap(getBitmap());
    }

    public Bitmap getBitmap(){
        Bitmap bitmap = Bitmap.createBitmap(mbitmap.getWidth(),
                mbitmap.getHeight(), Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(bitmap);

        Paint paint = new Paint();
        paint.setColorFilter(new ColorMatrixColorFilter(
                getColorMatrix()));
        canvas.drawBitmap(mbitmap, 0, 0, paint);

        return bitmap;
    }

    private ColorMatrix getColorMatrix() {
        ColorMatrix colorMatrix = new ColorMatrix();
        colorMatrix.setSaturation(0.5f);
        return colorMatrix;
    }


}