javacv-webcam

A project which shows how to use JavaFX together with OpenCV / JavaCV bindings.

This project can be used as a starting point for experiments with OpenCV and Java. It showcases the usage of the PixelBuffer API which permits a fast display / rendering of a webcam image stream with JavaFX.

Furthermore it uses javafx-maven-plugin to generate a custom java image.

You will need at least Java11 and Maven 3.6.2 to build.

Compile and run with javafx-maven-plugin

For a quick glimpse of what this project does just checkout the code and enter

mvn javafx:run -Djavacpp.platform.custom -Djavacpp.platform.host

Note: Providing javacpp properties is not mandatory, but it reduces download size for bytedeco significantly (only fetches libs for your platform - remember to always provide those parameters though).

After downloading dependencies and compiling a window should appear with your webcam image stream.

If you want to create a custom jre distribution, enter

mvn javafx:jlink -Djavacpp.platform.custom -Djavacpp.platform.host

which creates a custom JDK11 based distribution. You can start the application by entering

./target/javacv-webcam/bin/jwebcam

If you peek into the javacv-webcam directory.

Attention: If you are using Windows or Linux you'll have to adapt module-info.java to include native libraries of suitable for those platforms. On MacOsX, you may have problems with permissions to access your webcam from a java application, make sure to allow access in your system preferences.

Compile and run with client-maven-plugin

This project contains also a configuration for compiling it to a native image using GraalVM. You have to download and install GraalVM in a recent version (I tested it with 20.2.0) and then compile and run it with following command:

mvn clean client:build client:run -Djavacpp.platform.custom -Djavacpp.platform.host -Dgraalvm.home=/path/to/your/graalvm/distribution

After downloading necessary toolings, dependencies and compiling and linking (takes some time) a JavaFX application which uses your webcam will start.

Links

• Have a look at https://openjfx.io where you can find more information and introductory examples for developing JavaFX applications.
• https://github.com/bytedeco/javacv is the home of JavaCV which enables Java Developers to use native libraries like OpenCV.
• Some posts on http://ladstatt.blogspot.com/ may be of interest, too.