【安卓笔记】-----图片特效之怀旧风格

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分享一个图片特效-------怀旧效果

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算法：

经验公式如下：

R = 0.393r+0.769g+0.189b

G = 0.349r+0.686g+0.168b

B = 0.272r+0.534g+0.131b

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实现并测试：

新建一个activity，其中核心处理代码在func方法中。

package com.example.graphicsdemo2;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)    {        switch (v.getId())        {        case R.id.but_func:            func();            break;        case R.id.but_old:            iv_show.setImageResource(R.raw.girl);            break;        }    }            /**     * 怀旧效果     */    public void func()    {        Bitmap bitmap = BitmapFactory.decodeResource(getResources(),R.raw.girl);        int width = bitmap.getWidth();        int height = bitmap.getHeight();        Bitmap base = Bitmap.createBitmap(width, height,bitmap.getConfig());                Canvas canvas = new Canvas(base);//以base为模板创建canvas对象        canvas.drawBitmap(bitmap, new Matrix(),new Paint());                int newR,newG,newB;        for(int i = 0; i < width; i++)//遍历像素点        {            for(int j = 0; j < height; j++)            {                int current_color = bitmap.getPixel(i, j);                int r = Color.red(current_color);                int g = Color.green(current_color);                int b = Color.blue(current_color);                int a = Color.alpha(current_color);                                /*经验公式*/                newR = (int) (0.393 * r + 0.769 * g + 0.189 * b);                  newG = (int) (0.349 * r + 0.686 * g + 0.168 * b);                  newB = (int) (0.272 * r + 0.534 * g + 0.131 * b);                                  int newColor = Color.argb(a, newR > 255 ? 255 : newR, newG > 255 ? 255 : newG, newB > 255 ? 255 : newB);                 base.setPixel(i, j, newColor);            }        }        bitmap.recycle();        iv_show.setImageBitmap(base);    }}

处理前:

处理后：

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