https://github.com/logicsquad/nanocaptcha
A Java library for generating image and audio CAPTCHAs.
https://github.com/logicsquad/nanocaptcha
captcha java
Last synced: 24 days ago
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A Java library for generating image and audio CAPTCHAs.
- Host: GitHub
- URL: https://github.com/logicsquad/nanocaptcha
- Owner: logicsquad
- License: other
- Created: 2019-12-30T00:46:22.000Z (about 6 years ago)
- Default Branch: develop
- Last Pushed: 2025-04-26T05:27:26.000Z (9 months ago)
- Last Synced: 2025-07-13T04:41:20.176Z (7 months ago)
- Topics: captcha, java
- Language: Java
- Homepage:
- Size: 3.42 MB
- Stars: 46
- Watchers: 5
- Forks: 8
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- Changelog: CHANGELOG.md
- License: LICENSE.txt
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README
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NanoCaptcha
===========
What is this?
-------------
NanoCaptcha is a Java library for generating image and audio
CAPTCHAs. NanoCaptcha is intended to be:
* Self-contained: no network API hits to any external services.
* Minimally-dependent: using NanoCaptcha should not involve pulling in
a plethora of JARs, and ideally none at all.
Getting started
---------------
You can build a minimal image CAPTCHA very easily:
ImageCaptcha imageCaptcha = ImageCaptcha.create();
This creates a 200 x 50 pixel image and adds five random characters
from the Latin alphabet. The `getImage()` method returns the image as
a `BufferedImage` object. `isCorrect(String)` will verify the supplied
string against the text content of the image. If you need the text
content itself, call `getContent()`. Image CAPTCHAs can be further
customised by:
* Using different `ContentProducer`s (e.g., `ChineseContentProducer`).
* Supplying your own `Color`s and `Font`s.
* Adding noise using a `NoiseProducer`.
* Adding various `ImageFilter`s.
* Adding a background or a border.
To create a custom CAPTCHA, you can use an `ImageCaptcha.Builder`,
e.g.:
ImageCaptcha imageCaptcha = new ImageCaptcha.Builder(400, 100)
.addContent(new LatinContentProducer(7),
new DefaultWordRenderer.Builder()
.randomColor(Color.BLACK, Color.BLUE, Color.CYAN, Color.RED)
.build())
.addBackground(new GradiatedBackgroundProducer())
.addNoise(new CurvedLineNoiseProducer())
.build();
Building a minimal audio CAPTCHA is just as easy:
AudioCaptcha audioCaptcha = AudioCaptcha.create();
This creates a CAPTCHA with an audio clip containing five numbers read
out in English (unless the default `Locale` has been changed). To
customise your CAPTCHA, you can use `AudioCaptcha.Builder`.
There is support for different languages. (Currently English, German
and French are supported.) You can set the system property
`net.logicsquad.nanocaptcha.audio.producer.RandomNumberVoiceProducer.defaultLanguage`
to a 2-digit code for a supported language, e.g., `de`, and the
`Builder` above will return German digit vocalizations. Alternatively,
you can supply a `RandomNumberVoiceProducer` explicitly:
AudioCaptcha audioCaptcha = new AudioCaptcha.Builder()
.addContent()
.addVoice(new RandomNumberVoiceProducer(Locale.GERMAN))
.build();
You can even mix languages by calling `addVoice(Locale)` more than
once.
As with image CAPTCHAs, these can be further customised by:
* Adding background noise with a `NoiseProducer`.
Playing the audio is probably application-dependent, but the following
snippet will play the clip locally:
Clip clip = AudioSystem.getClip();
clip.open(audioCaptcha.getAudio().getAudioInputStream());
clip.start();
Thread.sleep(10000);
(The call to `Thread.sleep()` is simply to keep the JVM alive long
enough to play the clip.)
Using NanoCaptcha
-----------------
You can use NanoCaptcha in your projects by including it as a Maven dependency:
net.logicsquad
nanocaptcha
2.1
Contributing
------------
By all means, open issue tickets and pull requests if you have something
to contribute.
References
----------
NanoCaptcha is based on
[SimpleCaptcha](https://sourceforge.net/p/simplecaptcha/),
and incorporates code from
[JH Labs Java Image Filters](http://huxtable.com/ip/filters/).