添加文字水印

activity.xml

`

<TextView
    android:id="@+id/watermark_pic_title"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="水印" />

<ImageView
    android:id="@+id/wartermark_pic"
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:scaleType="centerInside"/>

`

MainActivity.class

public class MainActivity extends Activity {

    private ImageView mSourImage;
    private ImageView mWartermarkImage;

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

        initView();
    }

    private void initView(){

        mWartermarkImage = (ImageView) findViewById(R.id.wartermark_pic);
        Bitmap sourBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.sour_pic);


       Bitmap textBitmap = ImageUtil.drawTextToRightBottom(this, sourBitmap, "右下角", 40, Color.WHITE, 16, 16);

  mWartermarkImage.setImageBitmap(textBitmap);
    }
}

ImageUtils.class

public class ImageUtil {

//水印test
    private static Bitmap createWaterMaskBitmap(Bitmap src, Bitmap watermark,
                                                int paddingLeft, int paddingTop) {
        if (src == null) {
            return null;
        }
        int width = src.getWidth();
        int height = src.getHeight();
        //创建一个bitmap
        Bitmap newb = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);// 创建一个新的和SRC长度宽度一样的位图
        //将该图片作为画布
        Canvas canvas = new Canvas(newb);
        //在画布 0，0坐标上开始绘制原始图片
        canvas.drawBitmap(src, 0, 0, null);
        //在画布上绘制水印图片
        canvas.drawBitmap(watermark, paddingLeft, paddingTop, null);
        // 保存
        canvas.save(Canvas.ALL_SAVE_FLAG);
        // 存储
        canvas.restore();
        return newb;
    }







    /**
     * 绘制文字到右下角
     * @param context
     * @param bitmap
     * @param text
     * @param size
     * @param color
     * @param paddingBottom
     * @param paddingRight
     * @return
     */
    public static Bitmap drawTextToRightBottom(Context context, Bitmap bitmap, String text,
                                               int size, int color, int paddingRight, int paddingBottom) {
        Paint paint = new Paint(Paint.ANTI_ALIAS_FLAG);
        paint.setColor(color);
        paint.setTextSize(dp2px(context, size));
        Rect bounds = new Rect();
        paint.getTextBounds(text, 0, text.length(), bounds);
        return drawTextToBitmap(context, bitmap, text, paint, bounds,
                bitmap.getWidth() - bounds.width() - dp2px(context, paddingRight),
                bitmap.getHeight() - dp2px(context, paddingBottom));
    }




    //图片上绘制文字
    private static Bitmap drawTextToBitmap(Context context, Bitmap bitmap, String text,
                                           Paint paint, Rect bounds, int paddingLeft, int paddingTop) {
        android.graphics.Bitmap.Config bitmapConfig = bitmap.getConfig();

        paint.setDither(true); // 获取跟清晰的图像采样
        paint.setFilterBitmap(true);// 过滤一些
        if (bitmapConfig == null) {
            bitmapConfig = android.graphics.Bitmap.Config.ARGB_8888;
        }
        bitmap = bitmap.copy(bitmapConfig, true);
        Canvas canvas = new Canvas(bitmap);

        canvas.drawText(text, paddingLeft, paddingTop, paint);
        return bitmap;
    }

    /**
     * 缩放图片
     * @param src
     * @param w
     * @param h
     * @return
     */
    public static Bitmap scaleWithWH(Bitmap src, double w, double h) {
        if (w == 0 || h == 0 || src == null) {
            return src;
        } else {
            // 记录src的宽高
            int width = src.getWidth();
            int height = src.getHeight();
            // 创建一个matrix容器
            Matrix matrix = new Matrix();
            // 计算缩放比例
            float scaleWidth = (float) (w / width);
            float scaleHeight = (float) (h / height);
            // 开始缩放
            matrix.postScale(scaleWidth, scaleHeight);
            // 创建缩放后的图片
            return Bitmap.createBitmap(src, 0, 0, width, height, matrix, true);
        }
    }

    /**
     * dip转pix
     * @param context
     * @param dp
     * @return
     */
    public static int dp2px(Context context, float dp) {
        final float scale = context.getResources().getDisplayMetrics().density;
        return (int) (dp * scale + 0.5f);
    }
}

代码资源下载http://download.youkuaiyun.com/detail/grandaunt/9621992