简单的为图片添加水印

package com.zzw.addwatermark;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Bitmap.Config;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.drawable.BitmapDrawable;
import android.graphics.drawable.Drawable;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.ImageView;


public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        
        ImageView imageView=(ImageView) findViewById(R.id.imageView);
        
        //使用drawable里面的一张图片，我的头像为例
        Drawable drawable=getResources().getDrawable(R.drawable.test);
        
        //把Drawable转换为Bitmap
        BitmapDrawable bd=(BitmapDrawable) drawable; 
        Bitmap bm=bd.getBitmap();
        
        //为Bitmap添加水印
        Bitmap bitmap=createWatermark(bm, "www.cnblogs.com/zzw1994");
        imageView.setImageBitmap(bitmap);
    }
    
    // 为图片target添加水印文字  
    // Bitmap target：被添加水印的图片  
    // String mark：水印文章  
    private Bitmap createWatermark(Bitmap target,String mark){
        int width=target.getWidth();
        int height=target.getHeight();
        
        Bitmap bitmap=Bitmap.createBitmap(width, height, Config.ARGB_8888);
        Canvas canvas=new Canvas(bitmap);
        
        Paint paint=new Paint();
        
        //设置水印的颜色
        paint.setColor(Color.RED);
        //设置水印字体的大小
        paint.setTextSize(10);
        
        //去锯齿
        paint.setAntiAlias(true);
        //获取原图片的内容
        canvas.drawBitmap(target, 0, 0, paint);
        // 在最下方的左边位置开始添加水印  
        canvas.drawText(mark, 0, height, paint);
        
        canvas.save(Canvas.ALL_SAVE_FLAG);
        canvas.restore();
        
        
        return bitmap;
    }
    
}