Introduction: A lightweight android image watermark library that supports invisible digital watermarks. :foggy: (轻量级安卓水印框架,支持隐形数字水印)
More: Author   ReportBugs   OfficialWebsite   

Download Build Status Codacy Badge progress

A lightweight android image watermark library that supports encrypted watermarks. 中文版本

Download Library


implementation 'com.huangyz0918:androidwm:0.2.1'




<dependency org='com.huangyz0918' name='androidwm' rev='0.2.1'>
  <artifact name='androidwm' ext='pom' ></artifact>

Quick Start

Build a Watermark

After downloading the library and adding it into your project, You can create a WatermarkImage or WatermarkText and do some pre-settings with their instance.

    WatermarkText watermarkText = new WatermarkText(inputText)
            .setTextShadow(0.1f, 5, 5, Color.BLUE)

There are many attributes that can help you to make a customization with a text watermark or an image watermark. You can get more information from the documentation section that follows.

After the preparation is complete, you need a WatermarkBuilder to create a watermark image. You can get an instance from the create method of WatermarkBuilder, and, you need to put a Bitmap or an int Drawable as the background image first.

            .create(context, backgroundBitmap)
            .loadWatermarkText(watermarkText) // use .loadWatermarkImage(watermarkImage) to load an image.

Select the Drawing Mode

You can select normal mode (default) or tile mode in WatermarkBuilder.setTileMode():

            .create(this, backgroundBitmap)
            .setTileMode(true) // select different drawing mode.

Boom! the watermark has been drawed now:

Get the Output

You can create both text watermark and image watermark, and load them into your WatermarkBuilder. If you want to get the result bitmap, we also have a .getOutputImage() method for you after getting the watermark:

    Bitmap bitmap = WatermarkBuilder
            .create(this, backgroundBitmap)

Build Multiple Watermarks

And if you want to add many watermarks at the same time, you can use a List<> to hold your watermarks. You can add the List<> into the background image by .loadWatermarkTexts(watermarkTexts), the same as watermark images:

            .create(this, backgroundBitmap)

Ways of Loading Resources

If you want to load a watermark image or a watermark text from a view or resources, you can use those methods:

WatermarkText watermarkText = new WatermarkText(editText); // for a text from EditText.
WatermarkText watermarkText = new WatermarkText(textView); // for a text from TextView.
WatermarkImage watermarkImage = new WatermarkImage(imageView); // for an image from ImageView.
WatermarkImage watermarkImage = new WatermarkImage(this, R.drawable.image); // for an image from Resource.

The background loaded in WatermarkBuilder can be created from resources or ImageView too:

            .create(this, backgroundImageView) // .create(this, R.drawable.background)

If you didn't load a watermark ,the default value is as the same as background, nothing will be changed.

Invisible Watermarks (beta)

In this library, we also support the invisible watermark and the detection of them. We can use two ways to build a invisible watermark: the LSB (spatial domain) and the wavelet transform (Frequency domain). All you need to do is to use a boolean (isLSB) to distinguish them. (PS. the watermark in frequency domain is under developing)

You can create a new invisible watermark by the WatermarkBuilder's .setInvisibleWMListener:

            .create(this, backgroundBitmap)
            .setInvisibleWMListener(true, new BuildFinishListener<Bitmap>() {
                public void onSuccess(Bitmap object) {
                    if (object != null) {
                       // do something...

                public void onFailure(String message) {
                   // do something...

The first paramter of setInvisibleWMListener is isLSB, if false, the invisible algorithm will change to the frequency domain.

To detect the invisible watermark, you can use WatermarkDetector, the first paramter is the kind of watermark, if you want to detect the image watermark, the paramter is false, if it's a text, then true. The input bitmap is a image with invisible watermarks.

            .create(inputBitmap, true)
            .detect(false, new DetectFinishListener() {
                public void onImage(Bitmap watermark) {
                    if (watermark != null) {
                         // do something...

                public void onFailure(String message) {
                       // do something...

Here are the Demos for Least Significant Bits (LSB) invisible watermark:

Invisible Text (LSB) Invisible Image (LSB)

Enjoy yourself! :kissing_heart:

Detailed Usages


We use the class WatermarkPosition to control the position of a watermark.

   WatermarkPosition watermarkPosition = new WatermarkPosition(double position_x, double position_y, double rotation);
   WatermarkPosition watermarkPosition = new WatermarkPosition(double position_x, double position_y);

We can set the abscissa and ordinate of the watermark in the constructor, or you can optionally add the rotation angle. The coordinate system starts from the upper left corner of the background image, and the upper left corner is the origin.

The WatermarkPosition also supports change the position dynamically, androidwm offers several methods for you to modify the positions.


In full coverage mode (Tile mode), the positional parameters of the watermark image will be invalid.

x = y = 0, rotation = 15 x = y = 0.5, rotation = -15

Both the abscissa and the ordinate are a number from 0 to 1, representing a fixed proportion of the background image.

Color of Text Watermark

You can set the text color and background color in WatermarkText:

    WatermarkText watermarkText = new WatermarkText(editText)
            .setBackgroundColor(Color.WHITE); // if not, the background color will be transparent
color = green, background color = white color = green, background color = default

Text Shadow and Font

You can set the text font by loading a local resource, besides, you can also set the shadow by setTextShadow.

    WatermarkText watermarkText = new WatermarkText(editText)
            .setTextShadow(0.1f, 5, 5, Color.BLUE);
font = champagne shadow = (0.1f, 5, 5, BLUE)

the four parameters of text shadow is: (blur radius, x offset, y offset, color).

Text Size and Image Size

The text font size unit and the image size unit are different:

  • Text size is as the same unit as the android layout. (will auto adjust with the screen density and background pixels)
  • The image size is from 0 to 1, which is the width of the background image percentage.
image size = 0.3 text size = 40

Table of Methods

Here is a table of attributes in WatermarkText and WatermarkImage that you can custom with:

Method Description Default value
setPosition WatermarkPosition for the watermark null
setPositionX the x-axis coordinates of the watermark 0
setPositionY the y-axis coordinates of the watermark 0
setRotation the rotation of the watermark 0
setTextColor (WatermarkText) the text color of the WatermarkText Color.BLACK
setTextStyle (WatermarkText) the text style of the WatermarkText Paint.Style.FILL
setBackgroundColor (WatermarkText) the background color of the WatermarkText null
setTextAlpha (WatermarkText) the text alpha of the WatermarkText, from 0 to 255 50
setImageAlpha (WatermarkImage) the text alpha of the WatermarkImage, from 0 to 255 50
setTextSize (WatermarkText) the text size of the WatermarkText, consistent with the size unit used by the layout 20
setSize (WatermarkImage) the image size of the WatermarkImage, from 0 to 1 (the proportion of background size) 0.2
setTextFont (WatermarkText) typeface of the WatermarkText default
setTextShadow (WatermarkText) shadow of the WatermarkText (0, 0, 0)
setImageDrawable (WatermarkImage) image drawable of the WatermarkImage null

The basic methods of WatermarkImage are the same as WatermarkText.


   Copyright 2018 Yizheng Huang

   Licensed under the Apache License, Version 2.0 (the "License");
   you may not use this file except in compliance with the License.
   You may obtain a copy of the License at

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   See the License for the specific language governing permissions and
   limitations under the License.
Support Me
About Me
Google+: Trinea trinea
GitHub: Trinea