Bitmap添加水印效果

package com.loaderman.customviewdemo;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.os.Bundle;
import android.widget.ImageView;

public class MainActivity extends Activity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Bitmap bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.dog);
        Bitmap watermark = BitmapFactory.decodeResource(getResources(), R.drawable.watermark);
        Bitmap result = createBitmap(bitmap, watermark);

        ImageView imageView = (ImageView) findViewById(R.id.img);
        imageView.setImageBitmap(result);
    }

    private Bitmap createBitmap(Bitmap src, Bitmap watermark) {
        if (src == null) {
            return null;
        }

        int w = src.getWidth();
        int h = src.getHeight();
        int ww = watermark.getWidth();
        int wh = watermark.getHeight();
        //創建空白圖像
        Bitmap newb = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);//創建一個新的和SRC長度寬度一樣的位圖
        Canvas cv = new Canvas(newb);
        //畫原圖
        cv.drawBitmap(src, 0, 0, null);//在 0，0座標開始畫入src
        //在src的右下角畫入水印
        cv.drawBitmap(watermark, w - ww + 5, h - wh + 5, null);
        return newb;
    }
}